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linux-7.2.3/arch/x86/boot/startup/Makefile

@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0
+
+KBUILD_AFLAGS		+= -D__DISABLE_EXPORTS
+KBUILD_CFLAGS		+= -D__DISABLE_EXPORTS -mcmodel=small -fPIC \
+			   -Os -DDISABLE_BRANCH_PROFILING \
+			   $(DISABLE_STACKLEAK_PLUGIN) \
+			   $(DISABLE_LATENT_ENTROPY_PLUGIN) \
+			   -fno-stack-protector -D__NO_FORTIFY \
+			   -fno-jump-tables \
+			   -include $(srctree)/include/linux/hidden.h
+
+# disable ftrace hooks and LTO
+KBUILD_CFLAGS	:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS))
+KBUILD_CFLAGS	:= $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS))
+KASAN_SANITIZE	:= n
+KCSAN_SANITIZE	:= n
+KMSAN_SANITIZE	:= n
+UBSAN_SANITIZE	:= n
+KCOV_INSTRUMENT	:= n
+
+obj-$(CONFIG_X86_64)		+= gdt_idt.o map_kernel.o
+obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= sme.o sev-startup.o
+pi-objs				:= $(patsubst %.o,$(obj)/%.o,$(obj-y))
+
+lib-$(CONFIG_X86_64)		+= la57toggle.o
+lib-$(CONFIG_EFI_MIXED)		+= efi-mixed.o
+
+#
+# Disable objtool validation for all library code, which is intended
+# to be linked into the decompressor or the EFI stub but not vmlinux
+#
+$(patsubst %.o,$(obj)/%.o,$(lib-y)): OBJECT_FILES_NON_STANDARD := y
+
+#
+# Invoke objtool for each object individually to check for absolute
+# relocations, even if other objtool actions are being deferred.
+#
+$(pi-objs): objtool-enabled	= 1
+$(pi-objs): objtool-args	= $(if $(delay-objtool),--dry-run,$(objtool-args-y)) --noabs
+
+#
+# Confine the startup code by prefixing all symbols with __pi_ (for position
+# independent). This ensures that startup code can only call other startup
+# code, or code that has explicitly been made accessible to it via a symbol
+# alias.
+#
+$(obj)/%.pi.o: OBJCOPYFLAGS := --prefix-symbols=__pi_
+$(obj)/%.pi.o: $(obj)/%.o FORCE
+	$(call if_changed,objcopy)
+
+targets	+= $(obj-y)
+obj-y	:= $(patsubst %.o,%.pi.o,$(obj-y))

linux-7.2.3/arch/x86/boot/startup/efi-mixed.S

@@ -0,0 +1,253 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2014, 2015 Intel Corporation; author Matt Fleming
+ *
+ * Early support for invoking 32-bit EFI services from a 64-bit kernel.
+ *
+ * Because this thunking occurs before ExitBootServices() we have to
+ * restore the firmware's 32-bit GDT and IDT before we make EFI service
+ * calls.
+ *
+ * On the plus side, we don't have to worry about mangling 64-bit
+ * addresses into 32-bits because we're executing with an identity
+ * mapped pagetable and haven't transitioned to 64-bit virtual addresses
+ * yet.
+ */
+
+#include <linux/linkage.h>
+#include <asm/desc_defs.h>
+#include <asm/msr.h>
+#include <asm/page_types.h>
+#include <asm/pgtable_types.h>
+#include <asm/processor-flags.h>
+#include <asm/segment.h>
+
+	.text
+	.code32
+#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
+SYM_FUNC_START(efi32_stub_entry)
+	call	1f
+1:	popl	%ecx
+
+	/* Clear BSS */
+	xorl	%eax, %eax
+	leal	(_bss - 1b)(%ecx), %edi
+	leal	(_ebss - 1b)(%ecx), %ecx
+	subl	%edi, %ecx
+	shrl	$2, %ecx
+	cld
+	rep	stosl
+
+	add	$0x4, %esp		/* Discard return address */
+	movl	8(%esp), %ebx		/* struct boot_params pointer */
+	jmp	efi32_startup
+SYM_FUNC_END(efi32_stub_entry)
+#endif
+
+/*
+ * Called using a far call from __efi64_thunk() below, using the x86_64 SysV
+ * ABI (except for R8/R9 which are inaccessible to 32-bit code - EAX/EBX are
+ * used instead).  EBP+16 points to the arguments passed via the stack.
+ *
+ * The first argument (EDI) is a pointer to the boot service or protocol, to
+ * which the remaining arguments are passed, each truncated to 32 bits.
+ */
+SYM_FUNC_START_LOCAL(efi_enter32)
+	/*
+	 * Convert x86-64 SysV ABI params to i386 ABI
+	 */
+	pushl	32(%ebp)	/* Up to 3 args passed via the stack */
+	pushl	24(%ebp)
+	pushl	16(%ebp)
+	pushl	%ebx		/* R9 */
+	pushl	%eax		/* R8 */
+	pushl	%ecx
+	pushl	%edx
+	pushl	%esi
+
+	/* Disable paging */
+	movl	%cr0, %eax
+	btrl	$X86_CR0_PG_BIT, %eax
+	movl	%eax, %cr0
+
+	/* Disable long mode via EFER */
+	movl	$MSR_EFER, %ecx
+	rdmsr
+	btrl	$_EFER_LME, %eax
+	wrmsr
+
+	call	*%edi
+
+	/* We must preserve return value */
+	movl	%eax, %edi
+
+	call	efi32_enable_long_mode
+
+	addl	$32, %esp
+	movl	%edi, %eax
+	lret
+SYM_FUNC_END(efi_enter32)
+
+	.code64
+SYM_FUNC_START(__efi64_thunk)
+	push	%rbp
+	movl	%esp, %ebp
+	push	%rbx
+
+	/* Move args #5 and #6 into 32-bit accessible registers */
+	movl	%r8d, %eax
+	movl	%r9d, %ebx
+
+	lcalll	*efi32_call(%rip)
+
+	pop	%rbx
+	pop	%rbp
+	RET
+SYM_FUNC_END(__efi64_thunk)
+
+	.code32
+SYM_FUNC_START_LOCAL(efi32_enable_long_mode)
+	movl	%cr4, %eax
+	btsl	$(X86_CR4_PAE_BIT), %eax
+	movl	%eax, %cr4
+
+	movl	$MSR_EFER, %ecx
+	rdmsr
+	btsl	$_EFER_LME, %eax
+	wrmsr
+
+	/* Disable interrupts - the firmware's IDT does not work in long mode */
+	cli
+
+	/* Enable paging */
+	movl	%cr0, %eax
+	btsl	$X86_CR0_PG_BIT, %eax
+	movl	%eax, %cr0
+	ret
+SYM_FUNC_END(efi32_enable_long_mode)
+
+/*
+ * This is the common EFI stub entry point for mixed mode. It sets up the GDT
+ * and page tables needed for 64-bit execution, after which it calls the
+ * common 64-bit EFI entrypoint efi_stub_entry().
+ *
+ * Arguments:	0(%esp)	image handle
+ * 		4(%esp)	EFI system table pointer
+ *		%ebx	struct boot_params pointer (or NULL)
+ *
+ * Since this is the point of no return for ordinary execution, no registers
+ * are considered live except for the function parameters. [Note that the EFI
+ * stub may still exit and return to the firmware using the Exit() EFI boot
+ * service.]
+ */
+SYM_FUNC_START_LOCAL(efi32_startup)
+	movl	%esp, %ebp
+
+	subl	$8, %esp
+	sgdtl	(%esp)			/* Save GDT descriptor to the stack */
+	movl	2(%esp), %esi		/* Existing GDT pointer */
+	movzwl	(%esp), %ecx		/* Existing GDT limit */
+	inc	%ecx			/* Existing GDT size */
+	andl	$~7, %ecx		/* Ensure size is multiple of 8 */
+
+	subl	%ecx, %esp		/* Allocate new GDT */
+	andl	$~15, %esp		/* Realign the stack */
+	movl	%esp, %edi		/* New GDT address */
+	leal	7(%ecx), %eax		/* New GDT limit */
+	pushw	%cx			/* Push 64-bit CS (for LJMP below) */
+	pushl	%edi			/* Push new GDT address */
+	pushw	%ax			/* Push new GDT limit */
+
+	/* Copy GDT to the stack and add a 64-bit code segment at the end */
+	movl	$GDT_ENTRY(DESC_CODE64, 0, 0xfffff) & 0xffffffff, (%edi,%ecx)
+	movl	$GDT_ENTRY(DESC_CODE64, 0, 0xfffff) >> 32, 4(%edi,%ecx)
+	shrl	$2, %ecx
+	cld
+	rep	movsl			/* Copy the firmware GDT */
+	lgdtl	(%esp)			/* Switch to the new GDT */
+
+	call	1f
+1:	pop	%edi
+
+	/* Record mixed mode entry */
+	movb	$0x0, (efi_is64 - 1b)(%edi)
+
+	/* Set up indirect far call to re-enter 32-bit mode */
+	leal	(efi32_call - 1b)(%edi), %eax
+	addl	%eax, (%eax)
+	movw	%cs, 4(%eax)
+
+	/* Disable paging */
+	movl	%cr0, %eax
+	btrl	$X86_CR0_PG_BIT, %eax
+	movl	%eax, %cr0
+
+	/* Set up 1:1 mapping */
+	leal	(pte - 1b)(%edi), %eax
+	movl	$_PAGE_PRESENT | _PAGE_RW | _PAGE_PSE, %ecx
+	leal	(_PAGE_PRESENT | _PAGE_RW)(%eax), %edx
+2:	movl	%ecx, (%eax)
+	addl	$8, %eax
+	addl	$PMD_SIZE, %ecx
+	jnc	2b
+
+	movl	$PAGE_SIZE, %ecx
+	.irpc	l, 0123
+	movl	%edx, \l * 8(%eax)
+	addl	%ecx, %edx
+	.endr
+	addl	%ecx, %eax
+	movl	%edx, (%eax)
+	movl	%eax, %cr3
+
+	call	efi32_enable_long_mode
+
+	/* Set up far jump to 64-bit mode (CS is already on the stack) */
+	leal	(efi_stub_entry - 1b)(%edi), %eax
+	movl	%eax, 2(%esp)
+
+	movl	0(%ebp), %edi
+	movl	4(%ebp), %esi
+	movl	%ebx, %edx
+	ljmpl	*2(%esp)
+SYM_FUNC_END(efi32_startup)
+
+/*
+ * efi_status_t efi32_pe_entry(efi_handle_t image_handle,
+ *			       efi_system_table_32_t *sys_table)
+ */
+SYM_FUNC_START(efi32_pe_entry)
+	pushl	%ebx				// save callee-save registers
+
+	/* Check whether the CPU supports long mode */
+	movl	$0x80000001, %eax		// assume extended info support
+	cpuid
+	btl	$29, %edx			// check long mode bit
+	jnc	1f
+	leal	8(%esp), %esp			// preserve stack alignment
+	xor	%ebx, %ebx			// no struct boot_params pointer
+	jmp	efi32_startup			// only ESP and EBX remain live
+1:	movl	$0x80000003, %eax		// EFI_UNSUPPORTED
+	popl	%ebx
+	RET
+SYM_FUNC_END(efi32_pe_entry)
+
+#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
+	.org	efi32_stub_entry + 0x200
+	.code64
+SYM_FUNC_START_NOALIGN(efi64_stub_entry)
+	jmp	efi_handover_entry
+SYM_FUNC_END(efi64_stub_entry)
+#endif
+
+	.data
+	.balign	8
+SYM_DATA_START_LOCAL(efi32_call)
+	.long	efi_enter32 - .
+	.word	0x0
+SYM_DATA_END(efi32_call)
+SYM_DATA(efi_is64, .byte 1)
+
+	.bss
+	.balign PAGE_SIZE
+SYM_DATA_LOCAL(pte, .fill 6 * PAGE_SIZE, 1, 0)

linux-7.2.3/arch/x86/boot/startup/exports.h

@@ -0,0 +1,14 @@
+
+/*
+ * The symbols below are functions that are implemented by the startup code,
+ * but called at runtime by the SEV code residing in the core kernel.
+ */
+PROVIDE(early_set_pages_state		= __pi_early_set_pages_state);
+PROVIDE(early_snp_set_memory_private	= __pi_early_snp_set_memory_private);
+PROVIDE(early_snp_set_memory_shared	= __pi_early_snp_set_memory_shared);
+PROVIDE(get_hv_features			= __pi_get_hv_features);
+PROVIDE(sev_es_terminate		= __pi_sev_es_terminate);
+PROVIDE(snp_cpuid			= __pi_snp_cpuid);
+PROVIDE(snp_cpuid_get_table		= __pi_snp_cpuid_get_table);
+PROVIDE(svsm_issue_call			= __pi_svsm_issue_call);
+PROVIDE(svsm_process_result_codes	= __pi_svsm_process_result_codes);

linux-7.2.3/arch/x86/boot/startup/gdt_idt.c

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/linkage.h>
+#include <linux/types.h>
+
+#include <asm/desc.h>
+#include <asm/init.h>
+#include <asm/setup.h>
+#include <asm/sev.h>
+#include <asm/trapnr.h>
+
+/*
+ * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is
+ * used until the idt_table takes over. On the boot CPU this happens in
+ * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases
+ * this happens in the functions called from head_64.S.
+ *
+ * The idt_table can't be used that early because all the code modifying it is
+ * in idt.c and can be instrumented by tracing or KASAN, which both don't work
+ * during early CPU bringup. Also the idt_table has the runtime vectors
+ * configured which require certain CPU state to be setup already (like TSS),
+ * which also hasn't happened yet in early CPU bringup.
+ */
+static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data;
+
+/* This may run while still in the direct mapping */
+void startup_64_load_idt(void *vc_handler)
+{
+	struct desc_ptr desc = {
+		.address = (unsigned long)rip_rel_ptr(bringup_idt_table),
+		.size    = sizeof(bringup_idt_table) - 1,
+	};
+	struct idt_data data;
+	gate_desc idt_desc;
+
+	/* @vc_handler is set only for a VMM Communication Exception */
+	if (vc_handler) {
+		init_idt_data(&data, X86_TRAP_VC, vc_handler);
+		idt_init_desc(&idt_desc, &data);
+		native_write_idt_entry((gate_desc *)desc.address, X86_TRAP_VC, &idt_desc);
+	}
+
+	native_load_idt(&desc);
+}
+
+/*
+ * Setup boot CPU state needed before kernel switches to virtual addresses.
+ */
+void __init startup_64_setup_gdt_idt(void)
+{
+	struct gdt_page *gp = rip_rel_ptr((void *)(__force unsigned long)&gdt_page);
+	void *handler = NULL;
+
+	struct desc_ptr startup_gdt_descr = {
+		.address = (unsigned long)gp->gdt,
+		.size    = GDT_SIZE - 1,
+	};
+
+	/* Load GDT */
+	native_load_gdt(&startup_gdt_descr);
+
+	/* New GDT is live - reload data segment registers */
+	asm volatile("movl %%eax, %%ds\n"
+		     "movl %%eax, %%ss\n"
+		     "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");
+
+	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
+		handler = rip_rel_ptr(vc_no_ghcb);
+
+	startup_64_load_idt(handler);
+}

linux-7.2.3/arch/x86/boot/startup/la57toggle.S

@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/boot.h>
+#include <asm/msr.h>
+#include <asm/processor-flags.h>
+
+/*
+ * This is the 32-bit trampoline that will be copied over to low memory. It
+ * will be called using the ordinary 64-bit calling convention from code
+ * running in 64-bit mode.
+ *
+ * Return address is at the top of the stack (might be above 4G).
+ * The first argument (EDI) contains the address of the temporary PGD level
+ * page table in 32-bit addressable memory which will be programmed into
+ * register CR3.
+ */
+
+	.section ".rodata", "a", @progbits
+SYM_CODE_START(trampoline_32bit_src)
+	/*
+	 * Preserve callee save 64-bit registers on the stack: this is
+	 * necessary because the architecture does not guarantee that GPRs will
+	 * retain their full 64-bit values across a 32-bit mode switch.
+	 */
+	pushq	%r15
+	pushq	%r14
+	pushq	%r13
+	pushq	%r12
+	pushq	%rbp
+	pushq	%rbx
+
+	/* Preserve top half of RSP in a legacy mode GPR to avoid truncation */
+	movq	%rsp, %rbx
+	shrq	$32, %rbx
+
+	/* Switch to compatibility mode (CS.L = 0 CS.D = 1) via far return */
+	pushq	$__KERNEL32_CS
+	leaq	0f(%rip), %rax
+	pushq	%rax
+	lretq
+
+	/*
+	 * The 32-bit code below will do a far jump back to long mode and end
+	 * up here after reconfiguring the number of paging levels. First, the
+	 * stack pointer needs to be restored to its full 64-bit value before
+	 * the callee save register contents can be popped from the stack.
+	 */
+.Lret:
+	shlq	$32, %rbx
+	orq	%rbx, %rsp
+
+	/* Restore the preserved 64-bit registers */
+	popq	%rbx
+	popq	%rbp
+	popq	%r12
+	popq	%r13
+	popq	%r14
+	popq	%r15
+	retq
+
+	.code32
+0:
+	/* Disable paging */
+	movl	%cr0, %eax
+	btrl	$X86_CR0_PG_BIT, %eax
+	movl	%eax, %cr0
+
+	/* Point CR3 to the trampoline's new top level page table */
+	movl	%edi, %cr3
+
+	/* Set EFER.LME=1 as a precaution in case hypervsior pulls the rug */
+	movl	$MSR_EFER, %ecx
+	rdmsr
+	btsl	$_EFER_LME, %eax
+	/* Avoid writing EFER if no change was made (for TDX guest) */
+	jc	1f
+	wrmsr
+1:
+	/* Toggle CR4.LA57 */
+	movl	%cr4, %eax
+	btcl	$X86_CR4_LA57_BIT, %eax
+	movl	%eax, %cr4
+
+	/* Enable paging again. */
+	movl	%cr0, %eax
+	btsl	$X86_CR0_PG_BIT, %eax
+	movl	%eax, %cr0
+
+	/*
+	 * Return to the 64-bit calling code using LJMP rather than LRET, to
+	 * avoid the need for a 32-bit addressable stack. The destination
+	 * address will be adjusted after the template code is copied into a
+	 * 32-bit addressable buffer.
+	 */
+.Ljmp:	ljmpl	$__KERNEL_CS, $(.Lret - trampoline_32bit_src)
+SYM_CODE_END(trampoline_32bit_src)
+
+/*
+ * This symbol is placed right after trampoline_32bit_src() so its address can
+ * be used to infer the size of the trampoline code.
+ */
+SYM_DATA(trampoline_ljmp_imm_offset, .word  .Ljmp + 1 - trampoline_32bit_src)
+
+	/*
+         * The trampoline code has a size limit.
+         * Make sure we fail to compile if the trampoline code grows
+         * beyond TRAMPOLINE_32BIT_CODE_SIZE bytes.
+	 */
+	.org	trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_SIZE

linux-7.2.3/arch/x86/boot/startup/map_kernel.c

@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/pgtable.h>
+
+#include <asm/init.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/sev.h>
+
+extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
+extern unsigned int next_early_pgt;
+
+static inline bool check_la57_support(void)
+{
+	/*
+	 * 5-level paging is detected and enabled at kernel decompression
+	 * stage. Only check if it has been enabled there.
+	 */
+	if (!(native_read_cr4() & X86_CR4_LA57))
+		return false;
+
+	__pgtable_l5_enabled	= 1;
+	pgdir_shift		= 48;
+	ptrs_per_p4d		= 512;
+
+	return true;
+}
+
+static unsigned long __init sme_postprocess_startup(struct boot_params *bp,
+						    pmdval_t *pmd,
+						    unsigned long p2v_offset)
+{
+	unsigned long paddr, paddr_end;
+	int i;
+
+	/* Encrypt the kernel and related (if SME is active) */
+	sme_encrypt_kernel(bp);
+
+	/*
+	 * Clear the memory encryption mask from the .bss..decrypted section.
+	 * The bss section will be memset to zero later in the initialization so
+	 * there is no need to zero it after changing the memory encryption
+	 * attribute.
+	 */
+	if (sme_get_me_mask()) {
+		paddr = (unsigned long)rip_rel_ptr(__start_bss_decrypted);
+		paddr_end = (unsigned long)rip_rel_ptr(__end_bss_decrypted);
+
+		for (; paddr < paddr_end; paddr += PMD_SIZE) {
+			/*
+			 * On SNP, transition the page to shared in the RMP table so that
+			 * it is consistent with the page table attribute change.
+			 *
+			 * __start_bss_decrypted has a virtual address in the high range
+			 * mapping (kernel .text). PVALIDATE, by way of
+			 * early_snp_set_memory_shared(), requires a valid virtual
+			 * address but the kernel is currently running off of the identity
+			 * mapping so use the PA to get a *currently* valid virtual address.
+			 */
+			early_snp_set_memory_shared(paddr, paddr, PTRS_PER_PMD);
+
+			i = pmd_index(paddr - p2v_offset);
+			pmd[i] -= sme_get_me_mask();
+		}
+	}
+
+	/*
+	 * Return the SME encryption mask (if SME is active) to be used as a
+	 * modifier for the initial pgdir entry programmed into CR3.
+	 */
+	return sme_get_me_mask();
+}
+
+/*
+ * This code is compiled using PIC codegen because it will execute from the
+ * early 1:1 mapping of memory, which deviates from the mapping expected by the
+ * linker. Due to this deviation, taking the address of a global variable will
+ * produce an ambiguous result when using the plain & operator.  Instead,
+ * rip_rel_ptr() must be used, which will return the RIP-relative address in
+ * the 1:1 mapping of memory. Kernel virtual addresses can be determined by
+ * subtracting p2v_offset from the RIP-relative address.
+ */
+unsigned long __init __startup_64(unsigned long p2v_offset,
+				  struct boot_params *bp)
+{
+	pmd_t (*early_pgts)[PTRS_PER_PMD] = rip_rel_ptr(early_dynamic_pgts);
+	unsigned long physaddr = (unsigned long)rip_rel_ptr(_text);
+	unsigned long va_text, va_end;
+	unsigned long pgtable_flags;
+	unsigned long load_delta;
+	pgdval_t *pgd;
+	p4dval_t *p4d;
+	pudval_t *pud;
+	pmdval_t *pmd, pmd_entry;
+	bool la57;
+	int i;
+
+	la57 = check_la57_support();
+
+	/* Is the address too large? */
+	if (physaddr >> MAX_PHYSMEM_BITS)
+		for (;;);
+
+	/*
+	 * Compute the delta between the address I am compiled to run at
+	 * and the address I am actually running at.
+	 */
+	phys_base = load_delta = __START_KERNEL_map + p2v_offset;
+
+	/* Is the address not 2M aligned? */
+	if (load_delta & ~PMD_MASK)
+		for (;;);
+
+	va_text = physaddr - p2v_offset;
+	va_end  = (unsigned long)rip_rel_ptr(_end) - p2v_offset;
+
+	/* Include the SME encryption mask in the fixup value */
+	load_delta += sme_get_me_mask();
+
+	/* Fixup the physical addresses in the page table */
+
+	pgd = rip_rel_ptr(early_top_pgt);
+	pgd[pgd_index(__START_KERNEL_map)] += load_delta;
+
+	if (la57) {
+		p4d = (p4dval_t *)rip_rel_ptr(level4_kernel_pgt);
+		p4d[MAX_PTRS_PER_P4D - 1] += load_delta;
+
+		pgd[pgd_index(__START_KERNEL_map)] = (pgdval_t)p4d | _PAGE_TABLE;
+	}
+
+	level3_kernel_pgt[PTRS_PER_PUD - 2].pud += load_delta;
+	level3_kernel_pgt[PTRS_PER_PUD - 1].pud += load_delta;
+
+	for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
+		level2_fixmap_pgt[i].pmd += load_delta;
+
+	/*
+	 * Set up the identity mapping for the switchover.  These
+	 * entries should *NOT* have the global bit set!  This also
+	 * creates a bunch of nonsense entries but that is fine --
+	 * it avoids problems around wraparound.
+	 */
+
+	pud = &early_pgts[0]->pmd;
+	pmd = &early_pgts[1]->pmd;
+	next_early_pgt = 2;
+
+	pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
+
+	if (la57) {
+		p4d = &early_pgts[next_early_pgt++]->pmd;
+
+		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
+		pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
+		pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
+
+		i = physaddr >> P4D_SHIFT;
+		p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
+		p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
+	} else {
+		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
+		pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
+		pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
+	}
+
+	i = physaddr >> PUD_SHIFT;
+	pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
+	pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
+
+	pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
+	pmd_entry += sme_get_me_mask();
+	pmd_entry +=  physaddr;
+
+	for (i = 0; i < DIV_ROUND_UP(va_end - va_text, PMD_SIZE); i++) {
+		int idx = i + (physaddr >> PMD_SHIFT);
+
+		pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
+	}
+
+	/*
+	 * Fixup the kernel text+data virtual addresses. Note that
+	 * we might write invalid pmds, when the kernel is relocated
+	 * cleanup_highmap() fixes this up along with the mappings
+	 * beyond _end.
+	 *
+	 * Only the region occupied by the kernel image has so far
+	 * been checked against the table of usable memory regions
+	 * provided by the firmware, so invalidate pages outside that
+	 * region. A page table entry that maps to a reserved area of
+	 * memory would allow processor speculation into that area,
+	 * and on some hardware (particularly the UV platform) even
+	 * speculative access to some reserved areas is caught as an
+	 * error, causing the BIOS to halt the system.
+	 */
+
+	pmd = rip_rel_ptr(level2_kernel_pgt);
+
+	/* invalidate pages before the kernel image */
+	for (i = 0; i < pmd_index(va_text); i++)
+		pmd[i] &= ~_PAGE_PRESENT;
+
+	/* fixup pages that are part of the kernel image */
+	for (; i <= pmd_index(va_end); i++)
+		if (pmd[i] & _PAGE_PRESENT)
+			pmd[i] += load_delta;
+
+	/* invalidate pages after the kernel image */
+	for (; i < PTRS_PER_PMD; i++)
+		pmd[i] &= ~_PAGE_PRESENT;
+
+	return sme_postprocess_startup(bp, pmd, p2v_offset);
+}

linux-7.2.3/arch/x86/boot/startup/sev-shared.c

@@ -0,0 +1,762 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Encrypted Register State Support
+ *
+ * Author: Joerg Roedel <jroedel@suse.de>
+ *
+ * This file is not compiled stand-alone. It contains code shared
+ * between the pre-decompression boot code and the running Linux kernel
+ * and is included directly into both code-bases.
+ */
+
+#include <asm/setup_data.h>
+
+#ifndef __BOOT_COMPRESSED
+#define has_cpuflag(f)			cpu_feature_enabled(f)
+#else
+#undef WARN
+#define WARN(condition, format...) (!!(condition))
+#endif
+
+/* Copy of the SNP firmware's CPUID page. */
+static struct snp_cpuid_table cpuid_table_copy __ro_after_init;
+
+/*
+ * These will be initialized based on CPUID table so that non-present
+ * all-zero leaves (for sparse tables) can be differentiated from
+ * invalid/out-of-range leaves. This is needed since all-zero leaves
+ * still need to be post-processed.
+ */
+static u32 cpuid_std_range_max __ro_after_init;
+static u32 cpuid_hyp_range_max __ro_after_init;
+static u32 cpuid_ext_range_max __ro_after_init;
+
+bool sev_snp_needs_sfw __section(".data");
+
+void __noreturn
+sev_es_terminate(unsigned int set, unsigned int reason)
+{
+	u64 val = GHCB_MSR_TERM_REQ;
+
+	/* Tell the hypervisor what went wrong. */
+	val |= GHCB_SEV_TERM_REASON(set, reason);
+
+	/* Request Guest Termination from Hypervisor */
+	sev_es_wr_ghcb_msr(val);
+	VMGEXIT();
+
+	while (true)
+		asm volatile("hlt\n" : : : "memory");
+}
+
+/*
+ * The hypervisor features are available from GHCB version 2 onward.
+ */
+u64 __init get_hv_features(void)
+{
+	u64 val;
+
+	if (ghcb_version < 2)
+		return 0;
+
+	sev_es_wr_ghcb_msr(GHCB_MSR_HV_FT_REQ);
+	VMGEXIT();
+
+	val = sev_es_rd_ghcb_msr();
+	if (GHCB_RESP_CODE(val) != GHCB_MSR_HV_FT_RESP)
+		return 0;
+
+	return GHCB_MSR_HV_FT_RESP_VAL(val);
+}
+
+int svsm_process_result_codes(struct svsm_call *call)
+{
+	switch (call->rax_out) {
+	case SVSM_SUCCESS:
+		return 0;
+	case SVSM_ERR_INCOMPLETE:
+	case SVSM_ERR_BUSY:
+		return -EAGAIN;
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * Issue a VMGEXIT to call the SVSM:
+ *   - Load the SVSM register state (RAX, RCX, RDX, R8 and R9)
+ *   - Set the CA call pending field to 1
+ *   - Issue VMGEXIT
+ *   - Save the SVSM return register state (RAX, RCX, RDX, R8 and R9)
+ *   - Perform atomic exchange of the CA call pending field
+ *
+ *   - See the "Secure VM Service Module for SEV-SNP Guests" specification for
+ *     details on the calling convention.
+ *     - The calling convention loosely follows the Microsoft X64 calling
+ *       convention by putting arguments in RCX, RDX, R8 and R9.
+ *     - RAX specifies the SVSM protocol/callid as input and the return code
+ *       as output.
+ */
+void svsm_issue_call(struct svsm_call *call, u8 *pending)
+{
+	register unsigned long rax asm("rax") = call->rax;
+	register unsigned long rcx asm("rcx") = call->rcx;
+	register unsigned long rdx asm("rdx") = call->rdx;
+	register unsigned long r8  asm("r8")  = call->r8;
+	register unsigned long r9  asm("r9")  = call->r9;
+
+	call->caa->call_pending = 1;
+
+	asm volatile("rep; vmmcall\n\t"
+		     : "+r" (rax), "+r" (rcx), "+r" (rdx), "+r" (r8), "+r" (r9)
+		     : : "memory");
+
+	*pending = xchg(&call->caa->call_pending, *pending);
+
+	call->rax_out = rax;
+	call->rcx_out = rcx;
+	call->rdx_out = rdx;
+	call->r8_out  = r8;
+	call->r9_out  = r9;
+}
+
+int svsm_perform_msr_protocol(struct svsm_call *call)
+{
+	u8 pending = 0;
+	u64 val, resp;
+
+	/*
+	 * When using the MSR protocol, be sure to save and restore
+	 * the current MSR value.
+	 */
+	val = sev_es_rd_ghcb_msr();
+
+	sev_es_wr_ghcb_msr(GHCB_MSR_VMPL_REQ_LEVEL(0));
+
+	svsm_issue_call(call, &pending);
+
+	resp = sev_es_rd_ghcb_msr();
+
+	sev_es_wr_ghcb_msr(val);
+
+	if (pending)
+		return -EINVAL;
+
+	if (GHCB_RESP_CODE(resp) != GHCB_MSR_VMPL_RESP)
+		return -EINVAL;
+
+	if (GHCB_MSR_VMPL_RESP_VAL(resp))
+		return -EINVAL;
+
+	return svsm_process_result_codes(call);
+}
+
+static int __sev_cpuid_hv(u32 fn, int reg_idx, u32 *reg)
+{
+	u64 val;
+
+	sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(fn, reg_idx));
+	VMGEXIT();
+	val = sev_es_rd_ghcb_msr();
+	if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
+		return -EIO;
+
+	*reg = (val >> 32);
+
+	return 0;
+}
+
+static int __sev_cpuid_hv_msr(struct cpuid_leaf *leaf)
+{
+	int ret;
+
+	/*
+	 * MSR protocol does not support fetching non-zero subfunctions, but is
+	 * sufficient to handle current early-boot cases. Should that change,
+	 * make sure to report an error rather than ignoring the index and
+	 * grabbing random values. If this issue arises in the future, handling
+	 * can be added here to use GHCB-page protocol for cases that occur late
+	 * enough in boot that GHCB page is available.
+	 */
+	if (cpuid_function_is_indexed(leaf->fn) && leaf->subfn)
+		return -EINVAL;
+
+	ret =         __sev_cpuid_hv(leaf->fn, GHCB_CPUID_REQ_EAX, &leaf->eax);
+	ret = ret ? : __sev_cpuid_hv(leaf->fn, GHCB_CPUID_REQ_EBX, &leaf->ebx);
+	ret = ret ? : __sev_cpuid_hv(leaf->fn, GHCB_CPUID_REQ_ECX, &leaf->ecx);
+	ret = ret ? : __sev_cpuid_hv(leaf->fn, GHCB_CPUID_REQ_EDX, &leaf->edx);
+
+	return ret;
+}
+
+
+
+/*
+ * This may be called early while still running on the initial identity
+ * mapping. Use RIP-relative addressing to obtain the correct address
+ * while running with the initial identity mapping as well as the
+ * switch-over to kernel virtual addresses later.
+ */
+const struct snp_cpuid_table *snp_cpuid_get_table(void)
+{
+	return rip_rel_ptr(&cpuid_table_copy);
+}
+
+/*
+ * The SNP Firmware ABI, Revision 0.9, Section 7.1, details the use of
+ * XCR0_IN and XSS_IN to encode multiple versions of 0xD subfunctions 0
+ * and 1 based on the corresponding features enabled by a particular
+ * combination of XCR0 and XSS registers so that a guest can look up the
+ * version corresponding to the features currently enabled in its XCR0/XSS
+ * registers. The only values that differ between these versions/table
+ * entries is the enabled XSAVE area size advertised via EBX.
+ *
+ * While hypervisors may choose to make use of this support, it is more
+ * robust/secure for a guest to simply find the entry corresponding to the
+ * base/legacy XSAVE area size (XCR0=1 or XCR0=3), and then calculate the
+ * XSAVE area size using subfunctions 2 through 64, as documented in APM
+ * Volume 3, Rev 3.31, Appendix E.3.8, which is what is done here.
+ *
+ * Since base/legacy XSAVE area size is documented as 0x240, use that value
+ * directly rather than relying on the base size in the CPUID table.
+ *
+ * Return: XSAVE area size on success, 0 otherwise.
+ */
+static u32 snp_cpuid_calc_xsave_size(u64 xfeatures_en, bool compacted)
+{
+	const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
+	u64 xfeatures_found = 0;
+	u32 xsave_size = 0x240;
+	int i;
+
+	for (i = 0; i < cpuid_table->count; i++) {
+		const struct snp_cpuid_fn *e = &cpuid_table->fn[i];
+
+		if (!(e->eax_in == 0xD && e->ecx_in > 1 && e->ecx_in < 64))
+			continue;
+		if (!(xfeatures_en & (BIT_ULL(e->ecx_in))))
+			continue;
+		if (xfeatures_found & (BIT_ULL(e->ecx_in)))
+			continue;
+
+		xfeatures_found |= (BIT_ULL(e->ecx_in));
+
+		if (compacted)
+			xsave_size += e->eax;
+		else
+			xsave_size = max(xsave_size, e->eax + e->ebx);
+	}
+
+	/*
+	 * Either the guest set unsupported XCR0/XSS bits, or the corresponding
+	 * entries in the CPUID table were not present. This is not a valid
+	 * state to be in.
+	 */
+	if (xfeatures_found != (xfeatures_en & GENMASK_ULL(63, 2)))
+		return 0;
+
+	return xsave_size;
+}
+
+static bool
+snp_cpuid_get_validated_func(struct cpuid_leaf *leaf)
+{
+	const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
+	int i;
+
+	for (i = 0; i < cpuid_table->count; i++) {
+		const struct snp_cpuid_fn *e = &cpuid_table->fn[i];
+
+		if (e->eax_in != leaf->fn)
+			continue;
+
+		if (cpuid_function_is_indexed(leaf->fn) && e->ecx_in != leaf->subfn)
+			continue;
+
+		/*
+		 * For 0xD subfunctions 0 and 1, only use the entry corresponding
+		 * to the base/legacy XSAVE area size (XCR0=1 or XCR0=3, XSS=0).
+		 * See the comments above snp_cpuid_calc_xsave_size() for more
+		 * details.
+		 */
+		if (e->eax_in == 0xD && (e->ecx_in == 0 || e->ecx_in == 1))
+			if (!(e->xcr0_in == 1 || e->xcr0_in == 3) || e->xss_in)
+				continue;
+
+		leaf->eax = e->eax;
+		leaf->ebx = e->ebx;
+		leaf->ecx = e->ecx;
+		leaf->edx = e->edx;
+
+		return true;
+	}
+
+	return false;
+}
+
+static void snp_cpuid_hv_msr(void *ctx, struct cpuid_leaf *leaf)
+{
+	if (__sev_cpuid_hv_msr(leaf))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID_HV);
+}
+
+static int
+snp_cpuid_postprocess(void (*cpuid_fn)(void *ctx, struct cpuid_leaf *leaf),
+		      void *ctx, struct cpuid_leaf *leaf)
+{
+	struct cpuid_leaf leaf_hv = *leaf;
+
+	switch (leaf->fn) {
+	case 0x1:
+		cpuid_fn(ctx, &leaf_hv);
+
+		/* initial APIC ID */
+		leaf->ebx = (leaf_hv.ebx & GENMASK(31, 24)) | (leaf->ebx & GENMASK(23, 0));
+		/* APIC enabled bit */
+		leaf->edx = (leaf_hv.edx & BIT(9)) | (leaf->edx & ~BIT(9));
+
+		/* OSXSAVE enabled bit */
+		if (native_read_cr4() & X86_CR4_OSXSAVE)
+			leaf->ecx |= BIT(27);
+		break;
+	case 0x7:
+		/* OSPKE enabled bit */
+		leaf->ecx &= ~BIT(4);
+		if (native_read_cr4() & X86_CR4_PKE)
+			leaf->ecx |= BIT(4);
+		break;
+	case 0xB:
+		leaf_hv.subfn = 0;
+		cpuid_fn(ctx, &leaf_hv);
+
+		/* extended APIC ID */
+		leaf->edx = leaf_hv.edx;
+		break;
+	case 0xD: {
+		bool compacted = false;
+		u64 xcr0 = 1, xss = 0;
+		u32 xsave_size;
+
+		if (leaf->subfn != 0 && leaf->subfn != 1)
+			return 0;
+
+		if (native_read_cr4() & X86_CR4_OSXSAVE)
+			xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
+		if (leaf->subfn == 1) {
+			/* Get XSS value if XSAVES is enabled. */
+			if (leaf->eax & BIT(3)) {
+				unsigned long lo, hi;
+
+				asm volatile("rdmsr" : "=a" (lo), "=d" (hi)
+						     : "c" (MSR_IA32_XSS));
+				xss = (hi << 32) | lo;
+			}
+
+			/*
+			 * The PPR and APM aren't clear on what size should be
+			 * encoded in 0xD:0x1:EBX when compaction is not enabled
+			 * by either XSAVEC (feature bit 1) or XSAVES (feature
+			 * bit 3) since SNP-capable hardware has these feature
+			 * bits fixed as 1. KVM sets it to 0 in this case, but
+			 * to avoid this becoming an issue it's safer to simply
+			 * treat this as unsupported for SNP guests.
+			 */
+			if (!(leaf->eax & (BIT(1) | BIT(3))))
+				return -EINVAL;
+
+			compacted = true;
+		}
+
+		xsave_size = snp_cpuid_calc_xsave_size(xcr0 | xss, compacted);
+		if (!xsave_size)
+			return -EINVAL;
+
+		leaf->ebx = xsave_size;
+		}
+		break;
+	case 0x8000001E:
+		cpuid_fn(ctx, &leaf_hv);
+
+		/* extended APIC ID */
+		leaf->eax = leaf_hv.eax;
+		/* compute ID */
+		leaf->ebx = (leaf->ebx & GENMASK(31, 8)) | (leaf_hv.ebx & GENMASK(7, 0));
+		/* node ID */
+		leaf->ecx = (leaf->ecx & GENMASK(31, 8)) | (leaf_hv.ecx & GENMASK(7, 0));
+		break;
+	default:
+		/* No fix-ups needed, use values as-is. */
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * Returns -EOPNOTSUPP if feature not enabled. Any other non-zero return value
+ * should be treated as fatal by caller.
+ */
+int snp_cpuid(void (*cpuid_fn)(void *ctx, struct cpuid_leaf *leaf),
+	      void *ctx, struct cpuid_leaf *leaf)
+{
+	const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
+
+	if (!cpuid_table->count)
+		return -EOPNOTSUPP;
+
+	if (!snp_cpuid_get_validated_func(leaf)) {
+		/*
+		 * Some hypervisors will avoid keeping track of CPUID entries
+		 * where all values are zero, since they can be handled the
+		 * same as out-of-range values (all-zero). This is useful here
+		 * as well as it allows virtually all guest configurations to
+		 * work using a single SNP CPUID table.
+		 *
+		 * To allow for this, there is a need to distinguish between
+		 * out-of-range entries and in-range zero entries, since the
+		 * CPUID table entries are only a template that may need to be
+		 * augmented with additional values for things like
+		 * CPU-specific information during post-processing. So if it's
+		 * not in the table, set the values to zero. Then, if they are
+		 * within a valid CPUID range, proceed with post-processing
+		 * using zeros as the initial values. Otherwise, skip
+		 * post-processing and just return zeros immediately.
+		 */
+		leaf->eax = leaf->ebx = leaf->ecx = leaf->edx = 0;
+
+		/* Skip post-processing for out-of-range zero leafs. */
+		if (!(leaf->fn <= cpuid_std_range_max ||
+		      (leaf->fn >= 0x40000000 && leaf->fn <= cpuid_hyp_range_max) ||
+		      (leaf->fn >= 0x80000000 && leaf->fn <= cpuid_ext_range_max)))
+			return 0;
+	}
+
+	return snp_cpuid_postprocess(cpuid_fn, ctx, leaf);
+}
+
+/*
+ * Boot VC Handler - This is the first VC handler during boot, there is no GHCB
+ * page yet, so it only supports the MSR based communication with the
+ * hypervisor and only the CPUID exit-code.
+ */
+void do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
+{
+	unsigned int subfn = lower_bits(regs->cx, 32);
+	unsigned int fn = lower_bits(regs->ax, 32);
+	u16 opcode = *(unsigned short *)regs->ip;
+	struct cpuid_leaf leaf;
+	int ret;
+
+	/* Only CPUID is supported via MSR protocol */
+	if (exit_code != SVM_EXIT_CPUID)
+		goto fail;
+
+	/* Is it really a CPUID insn? */
+	if (opcode != 0xa20f)
+		goto fail;
+
+	leaf.fn = fn;
+	leaf.subfn = subfn;
+
+	/*
+	 * If SNP is active, then snp_cpuid() uses the CPUID table to obtain the
+	 * CPUID values (with possible HV interaction during post-processing of
+	 * the values). But if SNP is not active (no CPUID table present), then
+	 * snp_cpuid() returns -EOPNOTSUPP so that an SEV-ES guest can call the
+	 * HV to obtain the CPUID information.
+	 */
+	ret = snp_cpuid(snp_cpuid_hv_msr, NULL, &leaf);
+	if (!ret)
+		goto cpuid_done;
+
+	if (ret != -EOPNOTSUPP)
+		goto fail;
+
+	/*
+	 * This is reached by a SEV-ES guest and needs to invoke the HV for
+	 * the CPUID data.
+	 */
+	if (__sev_cpuid_hv_msr(&leaf))
+		goto fail;
+
+cpuid_done:
+	regs->ax = leaf.eax;
+	regs->bx = leaf.ebx;
+	regs->cx = leaf.ecx;
+	regs->dx = leaf.edx;
+
+	/*
+	 * This is a VC handler and the #VC is only raised when SEV-ES is
+	 * active, which means SEV must be active too. Do sanity checks on the
+	 * CPUID results to make sure the hypervisor does not trick the kernel
+	 * into the no-sev path. This could map sensitive data unencrypted and
+	 * make it accessible to the hypervisor.
+	 *
+	 * In particular, check for:
+	 *	- Availability of CPUID leaf 0x8000001f
+	 *	- SEV CPUID bit.
+	 *
+	 * The hypervisor might still report the wrong C-bit position, but this
+	 * can't be checked here.
+	 */
+
+	if (fn == 0x80000000 && (regs->ax < 0x8000001f))
+		/* SEV leaf check */
+		goto fail;
+	else if ((fn == 0x8000001f && !(regs->ax & BIT(1))))
+		/* SEV bit */
+		goto fail;
+
+	/* Skip over the CPUID two-byte opcode */
+	regs->ip += 2;
+
+	return;
+
+fail:
+	/* Terminate the guest */
+	sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
+}
+
+struct cc_setup_data {
+	struct setup_data header;
+	u32 cc_blob_address;
+};
+
+/*
+ * Search for a Confidential Computing blob passed in as a setup_data entry
+ * via the Linux Boot Protocol.
+ */
+static __init
+struct cc_blob_sev_info *find_cc_blob_setup_data(struct boot_params *bp)
+{
+	struct cc_setup_data *sd = NULL;
+	struct setup_data *hdr;
+
+	hdr = (struct setup_data *)bp->hdr.setup_data;
+
+	while (hdr) {
+		if (hdr->type == SETUP_CC_BLOB) {
+			sd = (struct cc_setup_data *)hdr;
+			return (struct cc_blob_sev_info *)(unsigned long)sd->cc_blob_address;
+		}
+		hdr = (struct setup_data *)hdr->next;
+	}
+
+	return NULL;
+}
+
+/*
+ * Initialize the kernel's copy of the SNP CPUID table, and set up the
+ * pointer that will be used to access it.
+ *
+ * Maintaining a direct mapping of the SNP CPUID table used by firmware would
+ * be possible as an alternative, but the approach is brittle since the
+ * mapping needs to be updated in sync with all the changes to virtual memory
+ * layout and related mapping facilities throughout the boot process.
+ */
+static void __init setup_cpuid_table(const struct cc_blob_sev_info *cc_info)
+{
+	const struct snp_cpuid_table *cpuid_table_fw, *cpuid_table;
+	int i;
+
+	if (!cc_info || !cc_info->cpuid_phys || cc_info->cpuid_len < PAGE_SIZE)
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID);
+
+	cpuid_table_fw = (const struct snp_cpuid_table *)cc_info->cpuid_phys;
+	if (!cpuid_table_fw->count || cpuid_table_fw->count > SNP_CPUID_COUNT_MAX)
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID);
+
+	cpuid_table = snp_cpuid_get_table();
+	memcpy((void *)cpuid_table, cpuid_table_fw, sizeof(*cpuid_table));
+
+	/* Initialize CPUID ranges for range-checking. */
+	for (i = 0; i < cpuid_table->count; i++) {
+		const struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
+
+		if (fn->eax_in == 0x0)
+			cpuid_std_range_max = fn->eax;
+		else if (fn->eax_in == 0x40000000)
+			cpuid_hyp_range_max = fn->eax;
+		else if (fn->eax_in == 0x80000000)
+			cpuid_ext_range_max = fn->eax;
+	}
+}
+
+static int svsm_call_msr_protocol(struct svsm_call *call)
+{
+	int ret;
+
+	do {
+		ret = svsm_perform_msr_protocol(call);
+	} while (ret == -EAGAIN);
+
+	return ret;
+}
+
+static void svsm_pval_4k_page(unsigned long paddr, bool validate,
+			      struct svsm_ca *caa, u64 caa_pa)
+{
+	struct svsm_pvalidate_call *pc;
+	struct svsm_call call = {};
+	unsigned long flags;
+	u64 pc_pa;
+
+	/*
+	 * This can be called very early in the boot, use native functions in
+	 * order to avoid paravirt issues.
+	 */
+	flags = native_local_irq_save();
+
+	call.caa = caa;
+
+	pc = (struct svsm_pvalidate_call *)call.caa->svsm_buffer;
+	pc_pa = caa_pa + offsetof(struct svsm_ca, svsm_buffer);
+
+	pc->num_entries = 1;
+	pc->cur_index   = 0;
+	pc->entry[0].page_size = RMP_PG_SIZE_4K;
+	pc->entry[0].action    = validate;
+	pc->entry[0].ignore_cf = 0;
+	pc->entry[0].rsvd      = 0;
+	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
+
+	/* Protocol 0, Call ID 1 */
+	call.rax = SVSM_CORE_CALL(SVSM_CORE_PVALIDATE);
+	call.rcx = pc_pa;
+
+	/*
+	 * Use the MSR protocol exclusively, so that this code is usable in
+	 * startup code where VA/PA translations of the GHCB page's address may
+	 * be problematic.
+	 */
+	if (svsm_call_msr_protocol(&call))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+
+	native_local_irq_restore(flags);
+}
+
+static void pvalidate_4k_page(unsigned long vaddr, unsigned long paddr,
+			      bool validate, struct svsm_ca *caa, u64 caa_pa)
+{
+	int ret;
+
+	if (snp_vmpl) {
+		svsm_pval_4k_page(paddr, validate, caa, caa_pa);
+	} else {
+		ret = pvalidate(vaddr, RMP_PG_SIZE_4K, validate);
+		if (ret)
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+	}
+
+	/*
+	 * If validating memory (making it private) and affected by the
+	 * cache-coherency vulnerability, perform the cache eviction mitigation.
+	 */
+	if (validate && sev_snp_needs_sfw)
+		sev_evict_cache((void *)vaddr, 1);
+}
+
+static void __page_state_change(unsigned long vaddr, unsigned long paddr,
+			        const struct psc_desc *desc)
+{
+	u64 val, msr;
+
+	/*
+	 * If private -> shared then invalidate the page before requesting the
+	 * state change in the RMP table.
+	 */
+	if (desc->op == SNP_PAGE_STATE_SHARED)
+		pvalidate_4k_page(vaddr, paddr, false, desc->ca, desc->caa_pa);
+
+	/* Save the current GHCB MSR value */
+	msr = sev_es_rd_ghcb_msr();
+
+	/* Issue VMGEXIT to change the page state in RMP table. */
+	sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, desc->op));
+	VMGEXIT();
+
+	/* Read the response of the VMGEXIT. */
+	val = sev_es_rd_ghcb_msr();
+	if ((GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP) || GHCB_MSR_PSC_RESP_VAL(val))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+
+	/* Restore the GHCB MSR value */
+	sev_es_wr_ghcb_msr(msr);
+
+	/*
+	 * Now that page state is changed in the RMP table, validate it so that it is
+	 * consistent with the RMP entry.
+	 */
+	if (desc->op == SNP_PAGE_STATE_PRIVATE)
+		pvalidate_4k_page(vaddr, paddr, true, desc->ca, desc->caa_pa);
+}
+
+/*
+ * Maintain the GPA of the SVSM Calling Area (CA) in order to utilize the SVSM
+ * services needed when not running in VMPL0.
+ */
+static bool __init svsm_setup_ca(const struct cc_blob_sev_info *cc_info,
+				 void *page)
+{
+	struct snp_secrets_page *secrets_page;
+	struct snp_cpuid_table *cpuid_table;
+	unsigned int i;
+	u64 caa;
+
+	BUILD_BUG_ON(sizeof(*secrets_page) != PAGE_SIZE);
+
+	/*
+	 * Check if running at VMPL0.
+	 *
+	 * Use RMPADJUST (see the rmpadjust() function for a description of what
+	 * the instruction does) to update the VMPL1 permissions of a page. If
+	 * the guest is running at VMPL0, this will succeed and implies there is
+	 * no SVSM. If the guest is running at any other VMPL, this will fail.
+	 * Linux SNP guests only ever run at a single VMPL level so permission mask
+	 * changes of a lesser-privileged VMPL are a don't-care.
+	 *
+	 * Use a rip-relative reference to obtain the proper address, since this
+	 * routine is running identity mapped when called, both by the decompressor
+	 * code and the early kernel code.
+	 */
+	if (!rmpadjust((unsigned long)page, RMP_PG_SIZE_4K, 1))
+		return false;
+
+	/*
+	 * Not running at VMPL0, ensure everything has been properly supplied
+	 * for running under an SVSM.
+	 */
+	if (!cc_info || !cc_info->secrets_phys || cc_info->secrets_len != PAGE_SIZE)
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECRETS_PAGE);
+
+	secrets_page = (struct snp_secrets_page *)cc_info->secrets_phys;
+	if (!secrets_page->svsm_size)
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NO_SVSM);
+
+	if (!secrets_page->svsm_guest_vmpl)
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_VMPL0);
+
+	snp_vmpl = secrets_page->svsm_guest_vmpl;
+
+	caa = secrets_page->svsm_caa;
+
+	/*
+	 * An open-coded PAGE_ALIGNED() in order to avoid including
+	 * kernel-proper headers into the decompressor.
+	 */
+	if (caa & (PAGE_SIZE - 1))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_CAA);
+
+	boot_svsm_caa_pa = caa;
+
+	/* Advertise the SVSM presence via CPUID. */
+	cpuid_table = (struct snp_cpuid_table *)snp_cpuid_get_table();
+	for (i = 0; i < cpuid_table->count; i++) {
+		struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
+
+		if (fn->eax_in == 0x8000001f)
+			fn->eax |= BIT(28);
+	}
+
+	return true;
+}

linux-7.2.3/arch/x86/boot/startup/sev-startup.c

@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2019 SUSE
+ *
+ * Author: Joerg Roedel <jroedel@suse.de>
+ */
+
+#define pr_fmt(fmt)	"SEV: " fmt
+
+#include <linux/percpu-defs.h>
+#include <linux/cc_platform.h>
+#include <linux/printk.h>
+#include <linux/mm_types.h>
+#include <linux/set_memory.h>
+#include <linux/memblock.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/cpumask.h>
+#include <linux/efi.h>
+#include <linux/io.h>
+#include <linux/psp-sev.h>
+#include <uapi/linux/sev-guest.h>
+
+#include <asm/init.h>
+#include <asm/cpu_entry_area.h>
+#include <asm/stacktrace.h>
+#include <asm/sev.h>
+#include <asm/insn-eval.h>
+#include <asm/fpu/xcr.h>
+#include <asm/processor.h>
+#include <asm/realmode.h>
+#include <asm/setup.h>
+#include <asm/traps.h>
+#include <asm/svm.h>
+#include <asm/smp.h>
+#include <asm/cpu.h>
+#include <asm/apic.h>
+#include <asm/cpuid/api.h>
+#include <asm/cmdline.h>
+
+#include "../../coco/sev/internal.h"
+
+/* Include code shared with pre-decompression boot stage */
+#include "sev-shared.c"
+
+void
+early_set_pages_state(unsigned long vaddr, unsigned long paddr,
+		      unsigned long npages, const struct psc_desc *desc)
+{
+	unsigned long paddr_end;
+
+	vaddr = vaddr & PAGE_MASK;
+
+	paddr = paddr & PAGE_MASK;
+	paddr_end = paddr + (npages << PAGE_SHIFT);
+
+	while (paddr < paddr_end) {
+		__page_state_change(vaddr, paddr, desc);
+
+		vaddr += PAGE_SIZE;
+		paddr += PAGE_SIZE;
+	}
+}
+
+void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
+					 unsigned long npages)
+{
+	struct psc_desc d = {
+		SNP_PAGE_STATE_PRIVATE,
+		rip_rel_ptr(&boot_svsm_ca_page),
+		boot_svsm_caa_pa
+	};
+
+	/*
+	 * This can be invoked in early boot while running identity mapped, so
+	 * use an open coded check for SNP instead of using cc_platform_has().
+	 * This eliminates worries about jump tables or checking boot_cpu_data
+	 * in the cc_platform_has() function.
+	 */
+	if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+		return;
+
+	 /*
+	  * Ask the hypervisor to mark the memory pages as private in the RMP
+	  * table.
+	  */
+	early_set_pages_state(vaddr, paddr, npages, &d);
+}
+
+void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
+					unsigned long npages)
+{
+	struct psc_desc d = {
+		SNP_PAGE_STATE_SHARED,
+		rip_rel_ptr(&boot_svsm_ca_page),
+		boot_svsm_caa_pa
+	};
+
+	/*
+	 * This can be invoked in early boot while running identity mapped, so
+	 * use an open coded check for SNP instead of using cc_platform_has().
+	 * This eliminates worries about jump tables or checking boot_cpu_data
+	 * in the cc_platform_has() function.
+	 */
+	if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+		return;
+
+	 /* Ask hypervisor to mark the memory pages shared in the RMP table. */
+	early_set_pages_state(vaddr, paddr, npages, &d);
+}
+
+/*
+ * Initial set up of SNP relies on information provided by the
+ * Confidential Computing blob, which can be passed to the kernel
+ * in the following ways, depending on how it is booted:
+ *
+ * - when booted via the boot/decompress kernel:
+ *   - via boot_params
+ *
+ * - when booted directly by firmware/bootloader (e.g. CONFIG_PVH):
+ *   - via a setup_data entry, as defined by the Linux Boot Protocol
+ *
+ * Scan for the blob in that order.
+ */
+static struct cc_blob_sev_info *__init find_cc_blob(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	/* Boot kernel would have passed the CC blob via boot_params. */
+	if (bp->cc_blob_address) {
+		cc_info = (struct cc_blob_sev_info *)(unsigned long)bp->cc_blob_address;
+		goto found_cc_info;
+	}
+
+	/*
+	 * If kernel was booted directly, without the use of the
+	 * boot/decompression kernel, the CC blob may have been passed via
+	 * setup_data instead.
+	 */
+	cc_info = find_cc_blob_setup_data(bp);
+	if (!cc_info)
+		return NULL;
+
+found_cc_info:
+	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+	return cc_info;
+}
+
+static void __init svsm_setup(struct cc_blob_sev_info *cc_info)
+{
+	struct snp_secrets_page *secrets = (void *)cc_info->secrets_phys;
+	struct svsm_call call = {};
+	u64 pa;
+
+	/*
+	 * Record the SVSM Calling Area address (CAA) if the guest is not
+	 * running at VMPL0. The CA will be used to communicate with the
+	 * SVSM to perform the SVSM services.
+	 */
+	if (!svsm_setup_ca(cc_info, rip_rel_ptr(&boot_svsm_ca_page)))
+		return;
+
+	/*
+	 * It is very early in the boot and the kernel is running identity
+	 * mapped but without having adjusted the pagetables to where the
+	 * kernel was loaded (physbase), so the get the CA address using
+	 * RIP-relative addressing.
+	 */
+	pa = (u64)rip_rel_ptr(&boot_svsm_ca_page);
+
+	/*
+	 * Switch over to the boot SVSM CA while the current CA is still 1:1
+	 * mapped and thus addressable with VA == PA. There is no GHCB at this
+	 * point so use the MSR protocol.
+	 *
+	 * SVSM_CORE_REMAP_CA call:
+	 *   RAX = 0 (Protocol=0, CallID=0)
+	 *   RCX = New CA GPA
+	 */
+	call.caa = (struct svsm_ca *)secrets->svsm_caa;
+	call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA);
+	call.rcx = pa;
+
+	if (svsm_call_msr_protocol(&call))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_CA_REMAP_FAIL);
+
+	boot_svsm_caa_pa = pa;
+}
+
+bool __init snp_init(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	if (!bp)
+		return false;
+
+	cc_info = find_cc_blob(bp);
+	if (!cc_info)
+		return false;
+
+	if (cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE)
+		sev_secrets_pa = cc_info->secrets_phys;
+	else
+		return false;
+
+	setup_cpuid_table(cc_info);
+
+	svsm_setup(cc_info);
+
+	/*
+	 * The CC blob will be used later to access the secrets page. Cache
+	 * it here like the boot kernel does.
+	 */
+	bp->cc_blob_address = (u32)(unsigned long)cc_info;
+
+	return true;
+}

linux-7.2.3/arch/x86/boot/startup/sme.c

@@ -0,0 +1,577 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ */
+
+/*
+ * Since we're dealing with identity mappings, physical and virtual
+ * addresses are the same, so override these defines which are ultimately
+ * used by the headers in misc.h.
+ */
+#define __pa(x)  ((unsigned long)(x))
+#define __va(x)  ((void *)((unsigned long)(x)))
+
+/*
+ * Special hack: we have to be careful, because no indirections are
+ * allowed here, and paravirt_ops is a kind of one. As it will only run in
+ * baremetal anyway, we just keep it from happening. (This list needs to
+ * be extended when new paravirt and debugging variants are added.)
+ */
+#undef CONFIG_PARAVIRT
+#undef CONFIG_PARAVIRT_XXL
+#undef CONFIG_PARAVIRT_SPINLOCKS
+#undef CONFIG_ARCH_HAS_LAZY_MMU_MODE
+
+/*
+ * This code runs before CPU feature bits are set. By default, the
+ * pgtable_l5_enabled() function uses bit X86_FEATURE_LA57 to determine if
+ * 5-level paging is active, so that won't work here. USE_EARLY_PGTABLE_L5
+ * is provided to handle this situation and, instead, use a variable that
+ * has been set by the early boot code.
+ */
+#define USE_EARLY_PGTABLE_L5
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
+
+#include <asm/init.h>
+#include <asm/setup.h>
+#include <asm/sections.h>
+#include <asm/cpuid/api.h>
+#include <asm/coco.h>
+#include <asm/sev.h>
+
+#define PGD_FLAGS		_KERNPG_TABLE_NOENC
+#define P4D_FLAGS		_KERNPG_TABLE_NOENC
+#define PUD_FLAGS		_KERNPG_TABLE_NOENC
+#define PMD_FLAGS		_KERNPG_TABLE_NOENC
+
+#define PMD_FLAGS_LARGE		(__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
+
+#define PMD_FLAGS_DEC		PMD_FLAGS_LARGE
+#define PMD_FLAGS_DEC_WP	((PMD_FLAGS_DEC & ~_PAGE_LARGE_CACHE_MASK) | \
+				 (_PAGE_PAT_LARGE | _PAGE_PWT))
+
+#define PMD_FLAGS_ENC		(PMD_FLAGS_LARGE | _PAGE_ENC)
+
+#define PTE_FLAGS		(__PAGE_KERNEL_EXEC & ~_PAGE_GLOBAL)
+
+#define PTE_FLAGS_DEC		PTE_FLAGS
+#define PTE_FLAGS_DEC_WP	((PTE_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
+				 (_PAGE_PAT | _PAGE_PWT))
+
+#define PTE_FLAGS_ENC		(PTE_FLAGS | _PAGE_ENC)
+
+struct sme_populate_pgd_data {
+	void    *pgtable_area;
+	pgd_t   *pgd;
+
+	pmdval_t pmd_flags;
+	pteval_t pte_flags;
+	unsigned long paddr;
+
+	unsigned long vaddr;
+	unsigned long vaddr_end;
+};
+
+/*
+ * This work area lives in the .init.scratch section, which lives outside of
+ * the kernel proper. It is sized to hold the intermediate copy buffer and
+ * more than enough pagetable pages.
+ *
+ * By using this section, the kernel can be encrypted in place and it
+ * avoids any possibility of boot parameters or initramfs images being
+ * placed such that the in-place encryption logic overwrites them.  This
+ * section is 2MB aligned to allow for simple pagetable setup using only
+ * PMD entries (see vmlinux.lds.S).
+ */
+static char sme_workarea[2 * PMD_SIZE] __section(".init.scratch");
+
+static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
+{
+	unsigned long pgd_start, pgd_end, pgd_size;
+	pgd_t *pgd_p;
+
+	pgd_start = ppd->vaddr & PGDIR_MASK;
+	pgd_end = ppd->vaddr_end & PGDIR_MASK;
+
+	pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);
+
+	pgd_p = ppd->pgd + pgd_index(ppd->vaddr);
+
+	memset(pgd_p, 0, pgd_size);
+}
+
+static pud_t __init *sme_prepare_pgd(struct sme_populate_pgd_data *ppd)
+{
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	pgd = ppd->pgd + pgd_index(ppd->vaddr);
+	if (pgd_none(*pgd)) {
+		p4d = ppd->pgtable_area;
+		memset(p4d, 0, sizeof(*p4d) * PTRS_PER_P4D);
+		ppd->pgtable_area += sizeof(*p4d) * PTRS_PER_P4D;
+		set_pgd(pgd, __pgd(PGD_FLAGS | __pa(p4d)));
+	}
+
+	p4d = p4d_offset(pgd, ppd->vaddr);
+	if (p4d_none(*p4d)) {
+		pud = ppd->pgtable_area;
+		memset(pud, 0, sizeof(*pud) * PTRS_PER_PUD);
+		ppd->pgtable_area += sizeof(*pud) * PTRS_PER_PUD;
+		set_p4d(p4d, __p4d(P4D_FLAGS | __pa(pud)));
+	}
+
+	pud = pud_offset(p4d, ppd->vaddr);
+	if (pud_none(*pud)) {
+		pmd = ppd->pgtable_area;
+		memset(pmd, 0, sizeof(*pmd) * PTRS_PER_PMD);
+		ppd->pgtable_area += sizeof(*pmd) * PTRS_PER_PMD;
+		set_pud(pud, __pud(PUD_FLAGS | __pa(pmd)));
+	}
+
+	if (pud_leaf(*pud))
+		return NULL;
+
+	return pud;
+}
+
+static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
+{
+	pud_t *pud;
+	pmd_t *pmd;
+
+	pud = sme_prepare_pgd(ppd);
+	if (!pud)
+		return;
+
+	pmd = pmd_offset(pud, ppd->vaddr);
+	if (pmd_leaf(*pmd))
+		return;
+
+	set_pmd(pmd, __pmd(ppd->paddr | ppd->pmd_flags));
+}
+
+static void __init sme_populate_pgd(struct sme_populate_pgd_data *ppd)
+{
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pud = sme_prepare_pgd(ppd);
+	if (!pud)
+		return;
+
+	pmd = pmd_offset(pud, ppd->vaddr);
+	if (pmd_none(*pmd)) {
+		pte = ppd->pgtable_area;
+		memset(pte, 0, sizeof(*pte) * PTRS_PER_PTE);
+		ppd->pgtable_area += sizeof(*pte) * PTRS_PER_PTE;
+		set_pmd(pmd, __pmd(PMD_FLAGS | __pa(pte)));
+	}
+
+	if (pmd_leaf(*pmd))
+		return;
+
+	pte = pte_offset_kernel(pmd, ppd->vaddr);
+	if (pte_none(*pte))
+		set_pte(pte, __pte(ppd->paddr | ppd->pte_flags));
+}
+
+static void __init __sme_map_range_pmd(struct sme_populate_pgd_data *ppd)
+{
+	while (ppd->vaddr < ppd->vaddr_end) {
+		sme_populate_pgd_large(ppd);
+
+		ppd->vaddr += PMD_SIZE;
+		ppd->paddr += PMD_SIZE;
+	}
+}
+
+static void __init __sme_map_range_pte(struct sme_populate_pgd_data *ppd)
+{
+	while (ppd->vaddr < ppd->vaddr_end) {
+		sme_populate_pgd(ppd);
+
+		ppd->vaddr += PAGE_SIZE;
+		ppd->paddr += PAGE_SIZE;
+	}
+}
+
+static void __init __sme_map_range(struct sme_populate_pgd_data *ppd,
+				   pmdval_t pmd_flags, pteval_t pte_flags)
+{
+	unsigned long vaddr_end;
+
+	ppd->pmd_flags = pmd_flags;
+	ppd->pte_flags = pte_flags;
+
+	/* Save original end value since we modify the struct value */
+	vaddr_end = ppd->vaddr_end;
+
+	/* If start is not 2MB aligned, create PTE entries */
+	ppd->vaddr_end = ALIGN(ppd->vaddr, PMD_SIZE);
+	__sme_map_range_pte(ppd);
+
+	/* Create PMD entries */
+	ppd->vaddr_end = vaddr_end & PMD_MASK;
+	__sme_map_range_pmd(ppd);
+
+	/* If end is not 2MB aligned, create PTE entries */
+	ppd->vaddr_end = vaddr_end;
+	__sme_map_range_pte(ppd);
+}
+
+static void __init sme_map_range_encrypted(struct sme_populate_pgd_data *ppd)
+{
+	__sme_map_range(ppd, PMD_FLAGS_ENC, PTE_FLAGS_ENC);
+}
+
+static void __init sme_map_range_decrypted(struct sme_populate_pgd_data *ppd)
+{
+	__sme_map_range(ppd, PMD_FLAGS_DEC, PTE_FLAGS_DEC);
+}
+
+static void __init sme_map_range_decrypted_wp(struct sme_populate_pgd_data *ppd)
+{
+	__sme_map_range(ppd, PMD_FLAGS_DEC_WP, PTE_FLAGS_DEC_WP);
+}
+
+static unsigned long __init sme_pgtable_calc(unsigned long len)
+{
+	unsigned long entries = 0, tables = 0;
+
+	/*
+	 * Perform a relatively simplistic calculation of the pagetable
+	 * entries that are needed. Those mappings will be covered mostly
+	 * by 2MB PMD entries so we can conservatively calculate the required
+	 * number of P4D, PUD and PMD structures needed to perform the
+	 * mappings.  For mappings that are not 2MB aligned, PTE mappings
+	 * would be needed for the start and end portion of the address range
+	 * that fall outside of the 2MB alignment.  This results in, at most,
+	 * two extra pages to hold PTE entries for each range that is mapped.
+	 * Incrementing the count for each covers the case where the addresses
+	 * cross entries.
+	 */
+
+	/* PGDIR_SIZE is equal to P4D_SIZE on 4-level machine. */
+	if (PTRS_PER_P4D > 1)
+		entries += (DIV_ROUND_UP(len, PGDIR_SIZE) + 1) * sizeof(p4d_t) * PTRS_PER_P4D;
+	entries += (DIV_ROUND_UP(len, P4D_SIZE) + 1) * sizeof(pud_t) * PTRS_PER_PUD;
+	entries += (DIV_ROUND_UP(len, PUD_SIZE) + 1) * sizeof(pmd_t) * PTRS_PER_PMD;
+	entries += 2 * sizeof(pte_t) * PTRS_PER_PTE;
+
+	/*
+	 * Now calculate the added pagetable structures needed to populate
+	 * the new pagetables.
+	 */
+
+	if (PTRS_PER_P4D > 1)
+		tables += DIV_ROUND_UP(entries, PGDIR_SIZE) * sizeof(p4d_t) * PTRS_PER_P4D;
+	tables += DIV_ROUND_UP(entries, P4D_SIZE) * sizeof(pud_t) * PTRS_PER_PUD;
+	tables += DIV_ROUND_UP(entries, PUD_SIZE) * sizeof(pmd_t) * PTRS_PER_PMD;
+
+	return entries + tables;
+}
+
+void __init sme_encrypt_kernel(struct boot_params *bp)
+{
+	unsigned long workarea_start, workarea_end, workarea_len;
+	unsigned long execute_start, execute_end, execute_len;
+	unsigned long kernel_start, kernel_end, kernel_len;
+	unsigned long initrd_start, initrd_end, initrd_len;
+	struct sme_populate_pgd_data ppd;
+	unsigned long pgtable_area_len;
+	unsigned long decrypted_base;
+
+	/*
+	 * This is early code, use an open coded check for SME instead of
+	 * using cc_platform_has(). This eliminates worries about removing
+	 * instrumentation or checking boot_cpu_data in the cc_platform_has()
+	 * function.
+	 */
+	if (!sme_get_me_mask() || sev_status & MSR_AMD64_SEV_ENABLED)
+		return;
+
+	/*
+	 * Prepare for encrypting the kernel and initrd by building new
+	 * pagetables with the necessary attributes needed to encrypt the
+	 * kernel in place.
+	 *
+	 *   One range of virtual addresses will map the memory occupied
+	 *   by the kernel and initrd as encrypted.
+	 *
+	 *   Another range of virtual addresses will map the memory occupied
+	 *   by the kernel and initrd as decrypted and write-protected.
+	 *
+	 *     The use of write-protect attribute will prevent any of the
+	 *     memory from being cached.
+	 */
+
+	kernel_start = (unsigned long)rip_rel_ptr(_text);
+	kernel_end = ALIGN((unsigned long)rip_rel_ptr(_end), PMD_SIZE);
+	kernel_len = kernel_end - kernel_start;
+
+	initrd_start = 0;
+	initrd_end = 0;
+	initrd_len = 0;
+#ifdef CONFIG_BLK_DEV_INITRD
+	initrd_len = (unsigned long)bp->hdr.ramdisk_size |
+		     ((unsigned long)bp->ext_ramdisk_size << 32);
+	if (initrd_len) {
+		initrd_start = (unsigned long)bp->hdr.ramdisk_image |
+			       ((unsigned long)bp->ext_ramdisk_image << 32);
+		initrd_end = PAGE_ALIGN(initrd_start + initrd_len);
+		initrd_len = initrd_end - initrd_start;
+	}
+#endif
+
+	/*
+	 * Calculate required number of workarea bytes needed:
+	 *   executable encryption area size:
+	 *     stack page (PAGE_SIZE)
+	 *     encryption routine page (PAGE_SIZE)
+	 *     intermediate copy buffer (PMD_SIZE)
+	 *   pagetable structures for the encryption of the kernel
+	 *   pagetable structures for workarea (in case not currently mapped)
+	 */
+	execute_start = workarea_start = (unsigned long)rip_rel_ptr(sme_workarea);
+	execute_end = execute_start + (PAGE_SIZE * 2) + PMD_SIZE;
+	execute_len = execute_end - execute_start;
+
+	/*
+	 * One PGD for both encrypted and decrypted mappings and a set of
+	 * PUDs and PMDs for each of the encrypted and decrypted mappings.
+	 */
+	pgtable_area_len = sizeof(pgd_t) * PTRS_PER_PGD;
+	pgtable_area_len += sme_pgtable_calc(execute_end - kernel_start) * 2;
+	if (initrd_len)
+		pgtable_area_len += sme_pgtable_calc(initrd_len) * 2;
+
+	/* PUDs and PMDs needed in the current pagetables for the workarea */
+	pgtable_area_len += sme_pgtable_calc(execute_len + pgtable_area_len);
+
+	/*
+	 * The total workarea includes the executable encryption area and
+	 * the pagetable area. The start of the workarea is already 2MB
+	 * aligned, align the end of the workarea on a 2MB boundary so that
+	 * we don't try to create/allocate PTE entries from the workarea
+	 * before it is mapped.
+	 */
+	workarea_len = execute_len + pgtable_area_len;
+	workarea_end = ALIGN(workarea_start + workarea_len, PMD_SIZE);
+
+	/*
+	 * Set the address to the start of where newly created pagetable
+	 * structures (PGDs, PUDs and PMDs) will be allocated. New pagetable
+	 * structures are created when the workarea is added to the current
+	 * pagetables and when the new encrypted and decrypted kernel
+	 * mappings are populated.
+	 */
+	ppd.pgtable_area = (void *)execute_end;
+
+	/*
+	 * Make sure the current pagetable structure has entries for
+	 * addressing the workarea.
+	 */
+	ppd.pgd = (pgd_t *)native_read_cr3_pa();
+	ppd.paddr = workarea_start;
+	ppd.vaddr = workarea_start;
+	ppd.vaddr_end = workarea_end;
+	sme_map_range_decrypted(&ppd);
+
+	/* Flush the TLB - no globals so cr3 is enough */
+	native_write_cr3(__native_read_cr3());
+
+	/*
+	 * A new pagetable structure is being built to allow for the kernel
+	 * and initrd to be encrypted. It starts with an empty PGD that will
+	 * then be populated with new PUDs and PMDs as the encrypted and
+	 * decrypted kernel mappings are created.
+	 */
+	ppd.pgd = ppd.pgtable_area;
+	memset(ppd.pgd, 0, sizeof(pgd_t) * PTRS_PER_PGD);
+	ppd.pgtable_area += sizeof(pgd_t) * PTRS_PER_PGD;
+
+	/*
+	 * A different PGD index/entry must be used to get different
+	 * pagetable entries for the decrypted mapping. Choose the next
+	 * PGD index and convert it to a virtual address to be used as
+	 * the base of the mapping.
+	 */
+	decrypted_base = (pgd_index(workarea_end) + 1) & (PTRS_PER_PGD - 1);
+	if (initrd_len) {
+		unsigned long check_base;
+
+		check_base = (pgd_index(initrd_end) + 1) & (PTRS_PER_PGD - 1);
+		decrypted_base = max(decrypted_base, check_base);
+	}
+	decrypted_base <<= PGDIR_SHIFT;
+
+	/* Add encrypted kernel (identity) mappings */
+	ppd.paddr = kernel_start;
+	ppd.vaddr = kernel_start;
+	ppd.vaddr_end = kernel_end;
+	sme_map_range_encrypted(&ppd);
+
+	/* Add decrypted, write-protected kernel (non-identity) mappings */
+	ppd.paddr = kernel_start;
+	ppd.vaddr = kernel_start + decrypted_base;
+	ppd.vaddr_end = kernel_end + decrypted_base;
+	sme_map_range_decrypted_wp(&ppd);
+
+	if (initrd_len) {
+		/* Add encrypted initrd (identity) mappings */
+		ppd.paddr = initrd_start;
+		ppd.vaddr = initrd_start;
+		ppd.vaddr_end = initrd_end;
+		sme_map_range_encrypted(&ppd);
+		/*
+		 * Add decrypted, write-protected initrd (non-identity) mappings
+		 */
+		ppd.paddr = initrd_start;
+		ppd.vaddr = initrd_start + decrypted_base;
+		ppd.vaddr_end = initrd_end + decrypted_base;
+		sme_map_range_decrypted_wp(&ppd);
+	}
+
+	/* Add decrypted workarea mappings to both kernel mappings */
+	ppd.paddr = workarea_start;
+	ppd.vaddr = workarea_start;
+	ppd.vaddr_end = workarea_end;
+	sme_map_range_decrypted(&ppd);
+
+	ppd.paddr = workarea_start;
+	ppd.vaddr = workarea_start + decrypted_base;
+	ppd.vaddr_end = workarea_end + decrypted_base;
+	sme_map_range_decrypted(&ppd);
+
+	/* Perform the encryption */
+	sme_encrypt_execute(kernel_start, kernel_start + decrypted_base,
+			    kernel_len, workarea_start, (unsigned long)ppd.pgd);
+
+	if (initrd_len)
+		sme_encrypt_execute(initrd_start, initrd_start + decrypted_base,
+				    initrd_len, workarea_start,
+				    (unsigned long)ppd.pgd);
+
+	/*
+	 * At this point we are running encrypted.  Remove the mappings for
+	 * the decrypted areas - all that is needed for this is to remove
+	 * the PGD entry/entries.
+	 */
+	ppd.vaddr = kernel_start + decrypted_base;
+	ppd.vaddr_end = kernel_end + decrypted_base;
+	sme_clear_pgd(&ppd);
+
+	if (initrd_len) {
+		ppd.vaddr = initrd_start + decrypted_base;
+		ppd.vaddr_end = initrd_end + decrypted_base;
+		sme_clear_pgd(&ppd);
+	}
+
+	ppd.vaddr = workarea_start + decrypted_base;
+	ppd.vaddr_end = workarea_end + decrypted_base;
+	sme_clear_pgd(&ppd);
+
+	/* Flush the TLB - no globals so cr3 is enough */
+	native_write_cr3(__native_read_cr3());
+}
+
+void __init sme_enable(struct boot_params *bp)
+{
+	unsigned int eax, ebx, ecx, edx;
+	unsigned long feature_mask;
+	unsigned long me_mask;
+	bool snp_en;
+	u64 msr;
+
+	snp_en = snp_init(bp);
+
+	/* Check for the SME/SEV support leaf */
+	eax = 0x80000000;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	if (eax < 0x8000001f)
+		return;
+
+#define AMD_SME_BIT	BIT(0)
+#define AMD_SEV_BIT	BIT(1)
+
+	/*
+	 * Check for the SME/SEV feature:
+	 *   CPUID Fn8000_001F[EAX]
+	 *   - Bit 0 - Secure Memory Encryption support
+	 *   - Bit 1 - Secure Encrypted Virtualization support
+	 *   CPUID Fn8000_001F[EBX]
+	 *   - Bits 5:0 - Pagetable bit position used to indicate encryption
+	 */
+	eax = 0x8000001f;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	/* Check whether SEV or SME is supported */
+	if (!(eax & (AMD_SEV_BIT | AMD_SME_BIT)))
+		return;
+
+	me_mask = 1UL << (ebx & 0x3f);
+	sev_snp_needs_sfw = !(ebx & BIT(31));
+
+	/* Check the SEV MSR whether SEV or SME is enabled */
+	sev_status = msr = native_rdmsrq(MSR_AMD64_SEV);
+	feature_mask = (msr & MSR_AMD64_SEV_ENABLED) ? AMD_SEV_BIT : AMD_SME_BIT;
+
+	/*
+	 * Any discrepancies between the presence of a CC blob and SNP
+	 * enablement abort the guest.
+	 */
+	if (snp_en ^ !!(msr & MSR_AMD64_SEV_SNP_ENABLED))
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+	/* Check if memory encryption is enabled */
+	if (feature_mask == AMD_SME_BIT) {
+		if (!(bp->hdr.xloadflags & XLF_MEM_ENCRYPTION))
+			return;
+
+		/*
+		 * No SME if Hypervisor bit is set. This check is here to
+		 * prevent a guest from trying to enable SME. For running as a
+		 * KVM guest the MSR_AMD64_SYSCFG will be sufficient, but there
+		 * might be other hypervisors which emulate that MSR as non-zero
+		 * or even pass it through to the guest.
+		 * A malicious hypervisor can still trick a guest into this
+		 * path, but there is no way to protect against that.
+		 */
+		eax = 1;
+		ecx = 0;
+		native_cpuid(&eax, &ebx, &ecx, &edx);
+		if (ecx & BIT(31))
+			return;
+
+		/* For SME, check the SYSCFG MSR */
+		msr = native_rdmsrq(MSR_AMD64_SYSCFG);
+		if (!(msr & MSR_AMD64_SYSCFG_MEM_ENCRYPT))
+			return;
+	}
+
+	sme_me_mask	= me_mask;
+	physical_mask	&= ~me_mask;
+	cc_vendor	= CC_VENDOR_AMD;
+	cc_set_mask(me_mask);
+}
+
+#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
+/* Local version for startup code, which never operates on user page tables */
+pgd_t __pti_set_user_pgtbl(pgd_t *pgdp, pgd_t pgd)
+{
+	return pgd;
+}
+#endif