Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2264 insertions, 0 deletions

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
new file mode 100644
index 0000000000..d87c6ff1f5
--- /dev/null
+++ b/arch/x86/kernel/sev.c
@@ -0,0 +1,2264 @@
+// 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/sched/debug.h>	/* For show_regs() */
+#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/platform_device.h>
+#include <linux/io.h>
+#include <linux/psp-sev.h>
+#include <uapi/linux/sev-guest.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.h>
+#include <asm/cmdline.h>
+
+#define DR7_RESET_VALUE        0x400
+
+/* AP INIT values as documented in the APM2  section "Processor Initialization State" */
+#define AP_INIT_CS_LIMIT		0xffff
+#define AP_INIT_DS_LIMIT		0xffff
+#define AP_INIT_LDTR_LIMIT		0xffff
+#define AP_INIT_GDTR_LIMIT		0xffff
+#define AP_INIT_IDTR_LIMIT		0xffff
+#define AP_INIT_TR_LIMIT		0xffff
+#define AP_INIT_RFLAGS_DEFAULT		0x2
+#define AP_INIT_DR6_DEFAULT		0xffff0ff0
+#define AP_INIT_GPAT_DEFAULT		0x0007040600070406ULL
+#define AP_INIT_XCR0_DEFAULT		0x1
+#define AP_INIT_X87_FTW_DEFAULT		0x5555
+#define AP_INIT_X87_FCW_DEFAULT		0x0040
+#define AP_INIT_CR0_DEFAULT		0x60000010
+#define AP_INIT_MXCSR_DEFAULT		0x1f80
+
+/* For early boot hypervisor communication in SEV-ES enabled guests */
+static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE);
+
+/*
+ * Needs to be in the .data section because we need it NULL before bss is
+ * cleared
+ */
+static struct ghcb *boot_ghcb __section(".data");
+
+/* Bitmap of SEV features supported by the hypervisor */
+static u64 sev_hv_features __ro_after_init;
+
+/* #VC handler runtime per-CPU data */
+struct sev_es_runtime_data {
+	struct ghcb ghcb_page;
+
+	/*
+	 * Reserve one page per CPU as backup storage for the unencrypted GHCB.
+	 * It is needed when an NMI happens while the #VC handler uses the real
+	 * GHCB, and the NMI handler itself is causing another #VC exception. In
+	 * that case the GHCB content of the first handler needs to be backed up
+	 * and restored.
+	 */
+	struct ghcb backup_ghcb;
+
+	/*
+	 * Mark the per-cpu GHCBs as in-use to detect nested #VC exceptions.
+	 * There is no need for it to be atomic, because nothing is written to
+	 * the GHCB between the read and the write of ghcb_active. So it is safe
+	 * to use it when a nested #VC exception happens before the write.
+	 *
+	 * This is necessary for example in the #VC->NMI->#VC case when the NMI
+	 * happens while the first #VC handler uses the GHCB. When the NMI code
+	 * raises a second #VC handler it might overwrite the contents of the
+	 * GHCB written by the first handler. To avoid this the content of the
+	 * GHCB is saved and restored when the GHCB is detected to be in use
+	 * already.
+	 */
+	bool ghcb_active;
+	bool backup_ghcb_active;
+
+	/*
+	 * Cached DR7 value - write it on DR7 writes and return it on reads.
+	 * That value will never make it to the real hardware DR7 as debugging
+	 * is currently unsupported in SEV-ES guests.
+	 */
+	unsigned long dr7;
+};
+
+struct ghcb_state {
+	struct ghcb *ghcb;
+};
+
+static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
+static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa);
+
+struct sev_config {
+	__u64 debug		: 1,
+
+	      /*
+	       * A flag used by __set_pages_state() that indicates when the
+	       * per-CPU GHCB has been created and registered and thus can be
+	       * used by the BSP instead of the early boot GHCB.
+	       *
+	       * For APs, the per-CPU GHCB is created before they are started
+	       * and registered upon startup, so this flag can be used globally
+	       * for the BSP and APs.
+	       */
+	      ghcbs_initialized	: 1,
+
+	      __reserved	: 62;
+};
+
+static struct sev_config sev_cfg __read_mostly;
+
+static __always_inline bool on_vc_stack(struct pt_regs *regs)
+{
+	unsigned long sp = regs->sp;
+
+	/* User-mode RSP is not trusted */
+	if (user_mode(regs))
+		return false;
+
+	/* SYSCALL gap still has user-mode RSP */
+	if (ip_within_syscall_gap(regs))
+		return false;
+
+	return ((sp >= __this_cpu_ist_bottom_va(VC)) && (sp < __this_cpu_ist_top_va(VC)));
+}
+
+/*
+ * This function handles the case when an NMI is raised in the #VC
+ * exception handler entry code, before the #VC handler has switched off
+ * its IST stack. In this case, the IST entry for #VC must be adjusted,
+ * so that any nested #VC exception will not overwrite the stack
+ * contents of the interrupted #VC handler.
+ *
+ * The IST entry is adjusted unconditionally so that it can be also be
+ * unconditionally adjusted back in __sev_es_ist_exit(). Otherwise a
+ * nested sev_es_ist_exit() call may adjust back the IST entry too
+ * early.
+ *
+ * The __sev_es_ist_enter() and __sev_es_ist_exit() functions always run
+ * on the NMI IST stack, as they are only called from NMI handling code
+ * right now.
+ */
+void noinstr __sev_es_ist_enter(struct pt_regs *regs)
+{
+	unsigned long old_ist, new_ist;
+
+	/* Read old IST entry */
+	new_ist = old_ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]);
+
+	/*
+	 * If NMI happened while on the #VC IST stack, set the new IST
+	 * value below regs->sp, so that the interrupted stack frame is
+	 * not overwritten by subsequent #VC exceptions.
+	 */
+	if (on_vc_stack(regs))
+		new_ist = regs->sp;
+
+	/*
+	 * Reserve additional 8 bytes and store old IST value so this
+	 * adjustment can be unrolled in __sev_es_ist_exit().
+	 */
+	new_ist -= sizeof(old_ist);
+	*(unsigned long *)new_ist = old_ist;
+
+	/* Set new IST entry */
+	this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], new_ist);
+}
+
+void noinstr __sev_es_ist_exit(void)
+{
+	unsigned long ist;
+
+	/* Read IST entry */
+	ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]);
+
+	if (WARN_ON(ist == __this_cpu_ist_top_va(VC)))
+		return;
+
+	/* Read back old IST entry and write it to the TSS */
+	this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], *(unsigned long *)ist);
+}
+
+/*
+ * Nothing shall interrupt this code path while holding the per-CPU
+ * GHCB. The backup GHCB is only for NMIs interrupting this path.
+ *
+ * Callers must disable local interrupts around it.
+ */
+static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
+{
+	struct sev_es_runtime_data *data;
+	struct ghcb *ghcb;
+
+	WARN_ON(!irqs_disabled());
+
+	data = this_cpu_read(runtime_data);
+	ghcb = &data->ghcb_page;
+
+	if (unlikely(data->ghcb_active)) {
+		/* GHCB is already in use - save its contents */
+
+		if (unlikely(data->backup_ghcb_active)) {
+			/*
+			 * Backup-GHCB is also already in use. There is no way
+			 * to continue here so just kill the machine. To make
+			 * panic() work, mark GHCBs inactive so that messages
+			 * can be printed out.
+			 */
+			data->ghcb_active        = false;
+			data->backup_ghcb_active = false;
+
+			instrumentation_begin();
+			panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use");
+			instrumentation_end();
+		}
+
+		/* Mark backup_ghcb active before writing to it */
+		data->backup_ghcb_active = true;
+
+		state->ghcb = &data->backup_ghcb;
+
+		/* Backup GHCB content */
+		*state->ghcb = *ghcb;
+	} else {
+		state->ghcb = NULL;
+		data->ghcb_active = true;
+	}
+
+	return ghcb;
+}
+
+static inline u64 sev_es_rd_ghcb_msr(void)
+{
+	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
+}
+
+static __always_inline void sev_es_wr_ghcb_msr(u64 val)
+{
+	u32 low, high;
+
+	low  = (u32)(val);
+	high = (u32)(val >> 32);
+
+	native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high);
+}
+
+static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt,
+				unsigned char *buffer)
+{
+	return copy_from_kernel_nofault(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE);
+}
+
+static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt)
+{
+	char buffer[MAX_INSN_SIZE];
+	int insn_bytes;
+
+	insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer);
+	if (insn_bytes == 0) {
+		/* Nothing could be copied */
+		ctxt->fi.vector     = X86_TRAP_PF;
+		ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER;
+		ctxt->fi.cr2        = ctxt->regs->ip;
+		return ES_EXCEPTION;
+	} else if (insn_bytes == -EINVAL) {
+		/* Effective RIP could not be calculated */
+		ctxt->fi.vector     = X86_TRAP_GP;
+		ctxt->fi.error_code = 0;
+		ctxt->fi.cr2        = 0;
+		return ES_EXCEPTION;
+	}
+
+	if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes))
+		return ES_DECODE_FAILED;
+
+	if (ctxt->insn.immediate.got)
+		return ES_OK;
+	else
+		return ES_DECODE_FAILED;
+}
+
+static enum es_result __vc_decode_kern_insn(struct es_em_ctxt *ctxt)
+{
+	char buffer[MAX_INSN_SIZE];
+	int res, ret;
+
+	res = vc_fetch_insn_kernel(ctxt, buffer);
+	if (res) {
+		ctxt->fi.vector     = X86_TRAP_PF;
+		ctxt->fi.error_code = X86_PF_INSTR;
+		ctxt->fi.cr2        = ctxt->regs->ip;
+		return ES_EXCEPTION;
+	}
+
+	ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64);
+	if (ret < 0)
+		return ES_DECODE_FAILED;
+	else
+		return ES_OK;
+}
+
+static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
+{
+	if (user_mode(ctxt->regs))
+		return __vc_decode_user_insn(ctxt);
+	else
+		return __vc_decode_kern_insn(ctxt);
+}
+
+static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
+				   char *dst, char *buf, size_t size)
+{
+	unsigned long error_code = X86_PF_PROT | X86_PF_WRITE;
+
+	/*
+	 * This function uses __put_user() independent of whether kernel or user
+	 * memory is accessed. This works fine because __put_user() does no
+	 * sanity checks of the pointer being accessed. All that it does is
+	 * to report when the access failed.
+	 *
+	 * Also, this function runs in atomic context, so __put_user() is not
+	 * allowed to sleep. The page-fault handler detects that it is running
+	 * in atomic context and will not try to take mmap_sem and handle the
+	 * fault, so additional pagefault_enable()/disable() calls are not
+	 * needed.
+	 *
+	 * The access can't be done via copy_to_user() here because
+	 * vc_write_mem() must not use string instructions to access unsafe
+	 * memory. The reason is that MOVS is emulated by the #VC handler by
+	 * splitting the move up into a read and a write and taking a nested #VC
+	 * exception on whatever of them is the MMIO access. Using string
+	 * instructions here would cause infinite nesting.
+	 */
+	switch (size) {
+	case 1: {
+		u8 d1;
+		u8 __user *target = (u8 __user *)dst;
+
+		memcpy(&d1, buf, 1);
+		if (__put_user(d1, target))
+			goto fault;
+		break;
+	}
+	case 2: {
+		u16 d2;
+		u16 __user *target = (u16 __user *)dst;
+
+		memcpy(&d2, buf, 2);
+		if (__put_user(d2, target))
+			goto fault;
+		break;
+	}
+	case 4: {
+		u32 d4;
+		u32 __user *target = (u32 __user *)dst;
+
+		memcpy(&d4, buf, 4);
+		if (__put_user(d4, target))
+			goto fault;
+		break;
+	}
+	case 8: {
+		u64 d8;
+		u64 __user *target = (u64 __user *)dst;
+
+		memcpy(&d8, buf, 8);
+		if (__put_user(d8, target))
+			goto fault;
+		break;
+	}
+	default:
+		WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size);
+		return ES_UNSUPPORTED;
+	}
+
+	return ES_OK;
+
+fault:
+	if (user_mode(ctxt->regs))
+		error_code |= X86_PF_USER;
+
+	ctxt->fi.vector = X86_TRAP_PF;
+	ctxt->fi.error_code = error_code;
+	ctxt->fi.cr2 = (unsigned long)dst;
+
+	return ES_EXCEPTION;
+}
+
+static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
+				  char *src, char *buf, size_t size)
+{
+	unsigned long error_code = X86_PF_PROT;
+
+	/*
+	 * This function uses __get_user() independent of whether kernel or user
+	 * memory is accessed. This works fine because __get_user() does no
+	 * sanity checks of the pointer being accessed. All that it does is
+	 * to report when the access failed.
+	 *
+	 * Also, this function runs in atomic context, so __get_user() is not
+	 * allowed to sleep. The page-fault handler detects that it is running
+	 * in atomic context and will not try to take mmap_sem and handle the
+	 * fault, so additional pagefault_enable()/disable() calls are not
+	 * needed.
+	 *
+	 * The access can't be done via copy_from_user() here because
+	 * vc_read_mem() must not use string instructions to access unsafe
+	 * memory. The reason is that MOVS is emulated by the #VC handler by
+	 * splitting the move up into a read and a write and taking a nested #VC
+	 * exception on whatever of them is the MMIO access. Using string
+	 * instructions here would cause infinite nesting.
+	 */
+	switch (size) {
+	case 1: {
+		u8 d1;
+		u8 __user *s = (u8 __user *)src;
+
+		if (__get_user(d1, s))
+			goto fault;
+		memcpy(buf, &d1, 1);
+		break;
+	}
+	case 2: {
+		u16 d2;
+		u16 __user *s = (u16 __user *)src;
+
+		if (__get_user(d2, s))
+			goto fault;
+		memcpy(buf, &d2, 2);
+		break;
+	}
+	case 4: {
+		u32 d4;
+		u32 __user *s = (u32 __user *)src;
+
+		if (__get_user(d4, s))
+			goto fault;
+		memcpy(buf, &d4, 4);
+		break;
+	}
+	case 8: {
+		u64 d8;
+		u64 __user *s = (u64 __user *)src;
+		if (__get_user(d8, s))
+			goto fault;
+		memcpy(buf, &d8, 8);
+		break;
+	}
+	default:
+		WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size);
+		return ES_UNSUPPORTED;
+	}
+
+	return ES_OK;
+
+fault:
+	if (user_mode(ctxt->regs))
+		error_code |= X86_PF_USER;
+
+	ctxt->fi.vector = X86_TRAP_PF;
+	ctxt->fi.error_code = error_code;
+	ctxt->fi.cr2 = (unsigned long)src;
+
+	return ES_EXCEPTION;
+}
+
+static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
+					   unsigned long vaddr, phys_addr_t *paddr)
+{
+	unsigned long va = (unsigned long)vaddr;
+	unsigned int level;
+	phys_addr_t pa;
+	pgd_t *pgd;
+	pte_t *pte;
+
+	pgd = __va(read_cr3_pa());
+	pgd = &pgd[pgd_index(va)];
+	pte = lookup_address_in_pgd(pgd, va, &level);
+	if (!pte) {
+		ctxt->fi.vector     = X86_TRAP_PF;
+		ctxt->fi.cr2        = vaddr;
+		ctxt->fi.error_code = 0;
+
+		if (user_mode(ctxt->regs))
+			ctxt->fi.error_code |= X86_PF_USER;
+
+		return ES_EXCEPTION;
+	}
+
+	if (WARN_ON_ONCE(pte_val(*pte) & _PAGE_ENC))
+		/* Emulated MMIO to/from encrypted memory not supported */
+		return ES_UNSUPPORTED;
+
+	pa = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
+	pa |= va & ~page_level_mask(level);
+
+	*paddr = pa;
+
+	return ES_OK;
+}
+
+static enum es_result vc_ioio_check(struct es_em_ctxt *ctxt, u16 port, size_t size)
+{
+	BUG_ON(size > 4);
+
+	if (user_mode(ctxt->regs)) {
+		struct thread_struct *t = &current->thread;
+		struct io_bitmap *iobm = t->io_bitmap;
+		size_t idx;
+
+		if (!iobm)
+			goto fault;
+
+		for (idx = port; idx < port + size; ++idx) {
+			if (test_bit(idx, iobm->bitmap))
+				goto fault;
+		}
+	}
+
+	return ES_OK;
+
+fault:
+	ctxt->fi.vector = X86_TRAP_GP;
+	ctxt->fi.error_code = 0;
+
+	return ES_EXCEPTION;
+}
+
+/* Include code shared with pre-decompression boot stage */
+#include "sev-shared.c"
+
+static noinstr void __sev_put_ghcb(struct ghcb_state *state)
+{
+	struct sev_es_runtime_data *data;
+	struct ghcb *ghcb;
+
+	WARN_ON(!irqs_disabled());
+
+	data = this_cpu_read(runtime_data);
+	ghcb = &data->ghcb_page;
+
+	if (state->ghcb) {
+		/* Restore GHCB from Backup */
+		*ghcb = *state->ghcb;
+		data->backup_ghcb_active = false;
+		state->ghcb = NULL;
+	} else {
+		/*
+		 * Invalidate the GHCB so a VMGEXIT instruction issued
+		 * from userspace won't appear to be valid.
+		 */
+		vc_ghcb_invalidate(ghcb);
+		data->ghcb_active = false;
+	}
+}
+
+void noinstr __sev_es_nmi_complete(void)
+{
+	struct ghcb_state state;
+	struct ghcb *ghcb;
+
+	ghcb = __sev_get_ghcb(&state);
+
+	vc_ghcb_invalidate(ghcb);
+	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_NMI_COMPLETE);
+	ghcb_set_sw_exit_info_1(ghcb, 0);
+	ghcb_set_sw_exit_info_2(ghcb, 0);
+
+	sev_es_wr_ghcb_msr(__pa_nodebug(ghcb));
+	VMGEXIT();
+
+	__sev_put_ghcb(&state);
+}
+
+static u64 __init get_secrets_page(void)
+{
+	u64 pa_data = boot_params.cc_blob_address;
+	struct cc_blob_sev_info info;
+	void *map;
+
+	/*
+	 * The CC blob contains the address of the secrets page, check if the
+	 * blob is present.
+	 */
+	if (!pa_data)
+		return 0;
+
+	map = early_memremap(pa_data, sizeof(info));
+	if (!map) {
+		pr_err("Unable to locate SNP secrets page: failed to map the Confidential Computing blob.\n");
+		return 0;
+	}
+	memcpy(&info, map, sizeof(info));
+	early_memunmap(map, sizeof(info));
+
+	/* smoke-test the secrets page passed */
+	if (!info.secrets_phys || info.secrets_len != PAGE_SIZE)
+		return 0;
+
+	return info.secrets_phys;
+}
+
+static u64 __init get_snp_jump_table_addr(void)
+{
+	struct snp_secrets_page_layout *layout;
+	void __iomem *mem;
+	u64 pa, addr;
+
+	pa = get_secrets_page();
+	if (!pa)
+		return 0;
+
+	mem = ioremap_encrypted(pa, PAGE_SIZE);
+	if (!mem) {
+		pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n");
+		return 0;
+	}
+
+	layout = (__force struct snp_secrets_page_layout *)mem;
+
+	addr = layout->os_area.ap_jump_table_pa;
+	iounmap(mem);
+
+	return addr;
+}
+
+static u64 __init get_jump_table_addr(void)
+{
+	struct ghcb_state state;
+	unsigned long flags;
+	struct ghcb *ghcb;
+	u64 ret = 0;
+
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return get_snp_jump_table_addr();
+
+	local_irq_save(flags);
+
+	ghcb = __sev_get_ghcb(&state);
+
+	vc_ghcb_invalidate(ghcb);
+	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE);
+	ghcb_set_sw_exit_info_1(ghcb, SVM_VMGEXIT_GET_AP_JUMP_TABLE);
+	ghcb_set_sw_exit_info_2(ghcb, 0);
+
+	sev_es_wr_ghcb_msr(__pa(ghcb));
+	VMGEXIT();
+
+	if (ghcb_sw_exit_info_1_is_valid(ghcb) &&
+	    ghcb_sw_exit_info_2_is_valid(ghcb))
+		ret = ghcb->save.sw_exit_info_2;
+
+	__sev_put_ghcb(&state);
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static void early_set_pages_state(unsigned long vaddr, unsigned long paddr,
+				  unsigned long npages, enum psc_op op)
+{
+	unsigned long paddr_end;
+	u64 val;
+	int ret;
+
+	vaddr = vaddr & PAGE_MASK;
+
+	paddr = paddr & PAGE_MASK;
+	paddr_end = paddr + (npages << PAGE_SHIFT);
+
+	while (paddr < paddr_end) {
+		if (op == SNP_PAGE_STATE_SHARED) {
+			/* Page validation must be rescinded before changing to shared */
+			ret = pvalidate(vaddr, RMP_PG_SIZE_4K, false);
+			if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret))
+				goto e_term;
+		}
+
+		/*
+		 * Use the MSR protocol because this function can be called before
+		 * the GHCB is established.
+		 */
+		sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op));
+		VMGEXIT();
+
+		val = sev_es_rd_ghcb_msr();
+
+		if (WARN(GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP,
+			 "Wrong PSC response code: 0x%x\n",
+			 (unsigned int)GHCB_RESP_CODE(val)))
+			goto e_term;
+
+		if (WARN(GHCB_MSR_PSC_RESP_VAL(val),
+			 "Failed to change page state to '%s' paddr 0x%lx error 0x%llx\n",
+			 op == SNP_PAGE_STATE_PRIVATE ? "private" : "shared",
+			 paddr, GHCB_MSR_PSC_RESP_VAL(val)))
+			goto e_term;
+
+		if (op == SNP_PAGE_STATE_PRIVATE) {
+			/* Page validation must be performed after changing to private */
+			ret = pvalidate(vaddr, RMP_PG_SIZE_4K, true);
+			if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret))
+				goto e_term;
+		}
+
+		vaddr += PAGE_SIZE;
+		paddr += PAGE_SIZE;
+	}
+
+	return;
+
+e_term:
+	sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+}
+
+void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
+					 unsigned long npages)
+{
+	/*
+	 * 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, SNP_PAGE_STATE_PRIVATE);
+}
+
+void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
+					unsigned long npages)
+{
+	/*
+	 * 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, SNP_PAGE_STATE_SHARED);
+}
+
+void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op)
+{
+	unsigned long vaddr, npages;
+
+	vaddr = (unsigned long)__va(paddr);
+	npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+
+	if (op == SNP_PAGE_STATE_PRIVATE)
+		early_snp_set_memory_private(vaddr, paddr, npages);
+	else if (op == SNP_PAGE_STATE_SHARED)
+		early_snp_set_memory_shared(vaddr, paddr, npages);
+	else
+		WARN(1, "invalid memory op %d\n", op);
+}
+
+static unsigned long __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr,
+				       unsigned long vaddr_end, int op)
+{
+	struct ghcb_state state;
+	bool use_large_entry;
+	struct psc_hdr *hdr;
+	struct psc_entry *e;
+	unsigned long flags;
+	unsigned long pfn;
+	struct ghcb *ghcb;
+	int i;
+
+	hdr = &data->hdr;
+	e = data->entries;
+
+	memset(data, 0, sizeof(*data));
+	i = 0;
+
+	while (vaddr < vaddr_end && i < ARRAY_SIZE(data->entries)) {
+		hdr->end_entry = i;
+
+		if (is_vmalloc_addr((void *)vaddr)) {
+			pfn = vmalloc_to_pfn((void *)vaddr);
+			use_large_entry = false;
+		} else {
+			pfn = __pa(vaddr) >> PAGE_SHIFT;
+			use_large_entry = true;
+		}
+
+		e->gfn = pfn;
+		e->operation = op;
+
+		if (use_large_entry && IS_ALIGNED(vaddr, PMD_SIZE) &&
+		    (vaddr_end - vaddr) >= PMD_SIZE) {
+			e->pagesize = RMP_PG_SIZE_2M;
+			vaddr += PMD_SIZE;
+		} else {
+			e->pagesize = RMP_PG_SIZE_4K;
+			vaddr += PAGE_SIZE;
+		}
+
+		e++;
+		i++;
+	}
+
+	/* Page validation must be rescinded before changing to shared */
+	if (op == SNP_PAGE_STATE_SHARED)
+		pvalidate_pages(data);
+
+	local_irq_save(flags);
+
+	if (sev_cfg.ghcbs_initialized)
+		ghcb = __sev_get_ghcb(&state);
+	else
+		ghcb = boot_ghcb;
+
+	/* Invoke the hypervisor to perform the page state changes */
+	if (!ghcb || vmgexit_psc(ghcb, data))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+
+	if (sev_cfg.ghcbs_initialized)
+		__sev_put_ghcb(&state);
+
+	local_irq_restore(flags);
+
+	/* Page validation must be performed after changing to private */
+	if (op == SNP_PAGE_STATE_PRIVATE)
+		pvalidate_pages(data);
+
+	return vaddr;
+}
+
+static void set_pages_state(unsigned long vaddr, unsigned long npages, int op)
+{
+	struct snp_psc_desc desc;
+	unsigned long vaddr_end;
+
+	/* Use the MSR protocol when a GHCB is not available. */
+	if (!boot_ghcb)
+		return early_set_pages_state(vaddr, __pa(vaddr), npages, op);
+
+	vaddr = vaddr & PAGE_MASK;
+	vaddr_end = vaddr + (npages << PAGE_SHIFT);
+
+	while (vaddr < vaddr_end)
+		vaddr = __set_pages_state(&desc, vaddr, vaddr_end, op);
+}
+
+void snp_set_memory_shared(unsigned long vaddr, unsigned long npages)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	set_pages_state(vaddr, npages, SNP_PAGE_STATE_SHARED);
+}
+
+void snp_set_memory_private(unsigned long vaddr, unsigned long npages)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE);
+}
+
+void snp_accept_memory(phys_addr_t start, phys_addr_t end)
+{
+	unsigned long vaddr, npages;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	vaddr = (unsigned long)__va(start);
+	npages = (end - start) >> PAGE_SHIFT;
+
+	set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE);
+}
+
+static int snp_set_vmsa(void *va, bool vmsa)
+{
+	u64 attrs;
+
+	/*
+	 * Running at VMPL0 allows the kernel to change the VMSA bit for a page
+	 * using the RMPADJUST instruction. However, for the instruction to
+	 * succeed it must target the permissions of a lesser privileged
+	 * (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST
+	 * instruction in the AMD64 APM Volume 3).
+	 */
+	attrs = 1;
+	if (vmsa)
+		attrs |= RMPADJUST_VMSA_PAGE_BIT;
+
+	return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
+}
+
+#define __ATTR_BASE		(SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK)
+#define INIT_CS_ATTRIBS		(__ATTR_BASE | SVM_SELECTOR_READ_MASK | SVM_SELECTOR_CODE_MASK)
+#define INIT_DS_ATTRIBS		(__ATTR_BASE | SVM_SELECTOR_WRITE_MASK)
+
+#define INIT_LDTR_ATTRIBS	(SVM_SELECTOR_P_MASK | 2)
+#define INIT_TR_ATTRIBS		(SVM_SELECTOR_P_MASK | 3)
+
+static void *snp_alloc_vmsa_page(void)
+{
+	struct page *p;
+
+	/*
+	 * Allocate VMSA page to work around the SNP erratum where the CPU will
+	 * incorrectly signal an RMP violation #PF if a large page (2MB or 1GB)
+	 * collides with the RMP entry of VMSA page. The recommended workaround
+	 * is to not use a large page.
+	 *
+	 * Allocate an 8k page which is also 8k-aligned.
+	 */
+	p = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1);
+	if (!p)
+		return NULL;
+
+	split_page(p, 1);
+
+	/* Free the first 4k. This page may be 2M/1G aligned and cannot be used. */
+	__free_page(p);
+
+	return page_address(p + 1);
+}
+
+static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
+{
+	int err;
+
+	err = snp_set_vmsa(vmsa, false);
+	if (err)
+		pr_err("clear VMSA page failed (%u), leaking page\n", err);
+	else
+		free_page((unsigned long)vmsa);
+}
+
+static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
+{
+	struct sev_es_save_area *cur_vmsa, *vmsa;
+	struct ghcb_state state;
+	unsigned long flags;
+	struct ghcb *ghcb;
+	u8 sipi_vector;
+	int cpu, ret;
+	u64 cr4;
+
+	/*
+	 * The hypervisor SNP feature support check has happened earlier, just check
+	 * the AP_CREATION one here.
+	 */
+	if (!(sev_hv_features & GHCB_HV_FT_SNP_AP_CREATION))
+		return -EOPNOTSUPP;
+
+	/*
+	 * Verify the desired start IP against the known trampoline start IP
+	 * to catch any future new trampolines that may be introduced that
+	 * would require a new protected guest entry point.
+	 */
+	if (WARN_ONCE(start_ip != real_mode_header->trampoline_start,
+		      "Unsupported SNP start_ip: %lx\n", start_ip))
+		return -EINVAL;
+
+	/* Override start_ip with known protected guest start IP */
+	start_ip = real_mode_header->sev_es_trampoline_start;
+
+	/* Find the logical CPU for the APIC ID */
+	for_each_present_cpu(cpu) {
+		if (arch_match_cpu_phys_id(cpu, apic_id))
+			break;
+	}
+	if (cpu >= nr_cpu_ids)
+		return -EINVAL;
+
+	cur_vmsa = per_cpu(sev_vmsa, cpu);
+
+	/*
+	 * A new VMSA is created each time because there is no guarantee that
+	 * the current VMSA is the kernels or that the vCPU is not running. If
+	 * an attempt was done to use the current VMSA with a running vCPU, a
+	 * #VMEXIT of that vCPU would wipe out all of the settings being done
+	 * here.
+	 */
+	vmsa = (struct sev_es_save_area *)snp_alloc_vmsa_page();
+	if (!vmsa)
+		return -ENOMEM;
+
+	/* CR4 should maintain the MCE value */
+	cr4 = native_read_cr4() & X86_CR4_MCE;
+
+	/* Set the CS value based on the start_ip converted to a SIPI vector */
+	sipi_vector		= (start_ip >> 12);
+	vmsa->cs.base		= sipi_vector << 12;
+	vmsa->cs.limit		= AP_INIT_CS_LIMIT;
+	vmsa->cs.attrib		= INIT_CS_ATTRIBS;
+	vmsa->cs.selector	= sipi_vector << 8;
+
+	/* Set the RIP value based on start_ip */
+	vmsa->rip		= start_ip & 0xfff;
+
+	/* Set AP INIT defaults as documented in the APM */
+	vmsa->ds.limit		= AP_INIT_DS_LIMIT;
+	vmsa->ds.attrib		= INIT_DS_ATTRIBS;
+	vmsa->es		= vmsa->ds;
+	vmsa->fs		= vmsa->ds;
+	vmsa->gs		= vmsa->ds;
+	vmsa->ss		= vmsa->ds;
+
+	vmsa->gdtr.limit	= AP_INIT_GDTR_LIMIT;
+	vmsa->ldtr.limit	= AP_INIT_LDTR_LIMIT;
+	vmsa->ldtr.attrib	= INIT_LDTR_ATTRIBS;
+	vmsa->idtr.limit	= AP_INIT_IDTR_LIMIT;
+	vmsa->tr.limit		= AP_INIT_TR_LIMIT;
+	vmsa->tr.attrib		= INIT_TR_ATTRIBS;
+
+	vmsa->cr4		= cr4;
+	vmsa->cr0		= AP_INIT_CR0_DEFAULT;
+	vmsa->dr7		= DR7_RESET_VALUE;
+	vmsa->dr6		= AP_INIT_DR6_DEFAULT;
+	vmsa->rflags		= AP_INIT_RFLAGS_DEFAULT;
+	vmsa->g_pat		= AP_INIT_GPAT_DEFAULT;
+	vmsa->xcr0		= AP_INIT_XCR0_DEFAULT;
+	vmsa->mxcsr		= AP_INIT_MXCSR_DEFAULT;
+	vmsa->x87_ftw		= AP_INIT_X87_FTW_DEFAULT;
+	vmsa->x87_fcw		= AP_INIT_X87_FCW_DEFAULT;
+
+	/* SVME must be set. */
+	vmsa->efer		= EFER_SVME;
+
+	/*
+	 * Set the SNP-specific fields for this VMSA:
+	 *   VMPL level
+	 *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
+	 */
+	vmsa->vmpl		= 0;
+	vmsa->sev_features	= sev_status >> 2;
+
+	/* Switch the page over to a VMSA page now that it is initialized */
+	ret = snp_set_vmsa(vmsa, true);
+	if (ret) {
+		pr_err("set VMSA page failed (%u)\n", ret);
+		free_page((unsigned long)vmsa);
+
+		return -EINVAL;
+	}
+
+	/* Issue VMGEXIT AP Creation NAE event */
+	local_irq_save(flags);
+
+	ghcb = __sev_get_ghcb(&state);
+
+	vc_ghcb_invalidate(ghcb);
+	ghcb_set_rax(ghcb, vmsa->sev_features);
+	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION);
+	ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | SVM_VMGEXIT_AP_CREATE);
+	ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa));
+
+	sev_es_wr_ghcb_msr(__pa(ghcb));
+	VMGEXIT();
+
+	if (!ghcb_sw_exit_info_1_is_valid(ghcb) ||
+	    lower_32_bits(ghcb->save.sw_exit_info_1)) {
+		pr_err("SNP AP Creation error\n");
+		ret = -EINVAL;
+	}
+
+	__sev_put_ghcb(&state);
+
+	local_irq_restore(flags);
+
+	/* Perform cleanup if there was an error */
+	if (ret) {
+		snp_cleanup_vmsa(vmsa);
+		vmsa = NULL;
+	}
+
+	/* Free up any previous VMSA page */
+	if (cur_vmsa)
+		snp_cleanup_vmsa(cur_vmsa);
+
+	/* Record the current VMSA page */
+	per_cpu(sev_vmsa, cpu) = vmsa;
+
+	return ret;
+}
+
+void __init snp_set_wakeup_secondary_cpu(void)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	/*
+	 * Always set this override if SNP is enabled. This makes it the
+	 * required method to start APs under SNP. If the hypervisor does
+	 * not support AP creation, then no APs will be started.
+	 */
+	apic_update_callback(wakeup_secondary_cpu, wakeup_cpu_via_vmgexit);
+}
+
+int __init sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
+{
+	u16 startup_cs, startup_ip;
+	phys_addr_t jump_table_pa;
+	u64 jump_table_addr;
+	u16 __iomem *jump_table;
+
+	jump_table_addr = get_jump_table_addr();
+
+	/* On UP guests there is no jump table so this is not a failure */
+	if (!jump_table_addr)
+		return 0;
+
+	/* Check if AP Jump Table is page-aligned */
+	if (jump_table_addr & ~PAGE_MASK)
+		return -EINVAL;
+
+	jump_table_pa = jump_table_addr & PAGE_MASK;
+
+	startup_cs = (u16)(rmh->trampoline_start >> 4);
+	startup_ip = (u16)(rmh->sev_es_trampoline_start -
+			   rmh->trampoline_start);
+
+	jump_table = ioremap_encrypted(jump_table_pa, PAGE_SIZE);
+	if (!jump_table)
+		return -EIO;
+
+	writew(startup_ip, &jump_table[0]);
+	writew(startup_cs, &jump_table[1]);
+
+	iounmap(jump_table);
+
+	return 0;
+}
+
+/*
+ * This is needed by the OVMF UEFI firmware which will use whatever it finds in
+ * the GHCB MSR as its GHCB to talk to the hypervisor. So make sure the per-cpu
+ * runtime GHCBs used by the kernel are also mapped in the EFI page-table.
+ */
+int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
+{
+	struct sev_es_runtime_data *data;
+	unsigned long address, pflags;
+	int cpu;
+	u64 pfn;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
+		return 0;
+
+	pflags = _PAGE_NX | _PAGE_RW;
+
+	for_each_possible_cpu(cpu) {
+		data = per_cpu(runtime_data, cpu);
+
+		address = __pa(&data->ghcb_page);
+		pfn = address >> PAGE_SHIFT;
+
+		if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags))
+			return 1;
+	}
+
+	return 0;
+}
+
+static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
+{
+	struct pt_regs *regs = ctxt->regs;
+	enum es_result ret;
+	u64 exit_info_1;
+
+	/* Is it a WRMSR? */
+	exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0;
+
+	ghcb_set_rcx(ghcb, regs->cx);
+	if (exit_info_1) {
+		ghcb_set_rax(ghcb, regs->ax);
+		ghcb_set_rdx(ghcb, regs->dx);
+	}
+
+	ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, exit_info_1, 0);
+
+	if ((ret == ES_OK) && (!exit_info_1)) {
+		regs->ax = ghcb->save.rax;
+		regs->dx = ghcb->save.rdx;
+	}
+
+	return ret;
+}
+
+static void snp_register_per_cpu_ghcb(void)
+{
+	struct sev_es_runtime_data *data;
+	struct ghcb *ghcb;
+
+	data = this_cpu_read(runtime_data);
+	ghcb = &data->ghcb_page;
+
+	snp_register_ghcb_early(__pa(ghcb));
+}
+
+void setup_ghcb(void)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
+		return;
+
+	/*
+	 * Check whether the runtime #VC exception handler is active. It uses
+	 * the per-CPU GHCB page which is set up by sev_es_init_vc_handling().
+	 *
+	 * If SNP is active, register the per-CPU GHCB page so that the runtime
+	 * exception handler can use it.
+	 */
+	if (initial_vc_handler == (unsigned long)kernel_exc_vmm_communication) {
+		if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+			snp_register_per_cpu_ghcb();
+
+		sev_cfg.ghcbs_initialized = true;
+
+		return;
+	}
+
+	/*
+	 * Make sure the hypervisor talks a supported protocol.
+	 * This gets called only in the BSP boot phase.
+	 */
+	if (!sev_es_negotiate_protocol())
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
+
+	/*
+	 * Clear the boot_ghcb. The first exception comes in before the bss
+	 * section is cleared.
+	 */
+	memset(&boot_ghcb_page, 0, PAGE_SIZE);
+
+	/* Alright - Make the boot-ghcb public */
+	boot_ghcb = &boot_ghcb_page;
+
+	/* SNP guest requires that GHCB GPA must be registered. */
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		snp_register_ghcb_early(__pa(&boot_ghcb_page));
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void sev_es_ap_hlt_loop(void)
+{
+	struct ghcb_state state;
+	struct ghcb *ghcb;
+
+	ghcb = __sev_get_ghcb(&state);
+
+	while (true) {
+		vc_ghcb_invalidate(ghcb);
+		ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_HLT_LOOP);
+		ghcb_set_sw_exit_info_1(ghcb, 0);
+		ghcb_set_sw_exit_info_2(ghcb, 0);
+
+		sev_es_wr_ghcb_msr(__pa(ghcb));
+		VMGEXIT();
+
+		/* Wakeup signal? */
+		if (ghcb_sw_exit_info_2_is_valid(ghcb) &&
+		    ghcb->save.sw_exit_info_2)
+			break;
+	}
+
+	__sev_put_ghcb(&state);
+}
+
+/*
+ * Play_dead handler when running under SEV-ES. This is needed because
+ * the hypervisor can't deliver an SIPI request to restart the AP.
+ * Instead the kernel has to issue a VMGEXIT to halt the VCPU until the
+ * hypervisor wakes it up again.
+ */
+static void sev_es_play_dead(void)
+{
+	play_dead_common();
+
+	/* IRQs now disabled */
+
+	sev_es_ap_hlt_loop();
+
+	/*
+	 * If we get here, the VCPU was woken up again. Jump to CPU
+	 * startup code to get it back online.
+	 */
+	soft_restart_cpu();
+}
+#else  /* CONFIG_HOTPLUG_CPU */
+#define sev_es_play_dead	native_play_dead
+#endif /* CONFIG_HOTPLUG_CPU */
+
+#ifdef CONFIG_SMP
+static void __init sev_es_setup_play_dead(void)
+{
+	smp_ops.play_dead = sev_es_play_dead;
+}
+#else
+static inline void sev_es_setup_play_dead(void) { }
+#endif
+
+static void __init alloc_runtime_data(int cpu)
+{
+	struct sev_es_runtime_data *data;
+
+	data = memblock_alloc(sizeof(*data), PAGE_SIZE);
+	if (!data)
+		panic("Can't allocate SEV-ES runtime data");
+
+	per_cpu(runtime_data, cpu) = data;
+}
+
+static void __init init_ghcb(int cpu)
+{
+	struct sev_es_runtime_data *data;
+	int err;
+
+	data = per_cpu(runtime_data, cpu);
+
+	err = early_set_memory_decrypted((unsigned long)&data->ghcb_page,
+					 sizeof(data->ghcb_page));
+	if (err)
+		panic("Can't map GHCBs unencrypted");
+
+	memset(&data->ghcb_page, 0, sizeof(data->ghcb_page));
+
+	data->ghcb_active = false;
+	data->backup_ghcb_active = false;
+}
+
+void __init sev_es_init_vc_handling(void)
+{
+	int cpu;
+
+	BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE);
+
+	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
+		return;
+
+	if (!sev_es_check_cpu_features())
+		panic("SEV-ES CPU Features missing");
+
+	/*
+	 * SNP is supported in v2 of the GHCB spec which mandates support for HV
+	 * features.
+	 */
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+		sev_hv_features = get_hv_features();
+
+		if (!(sev_hv_features & GHCB_HV_FT_SNP))
+			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+	}
+
+	/* Initialize per-cpu GHCB pages */
+	for_each_possible_cpu(cpu) {
+		alloc_runtime_data(cpu);
+		init_ghcb(cpu);
+	}
+
+	sev_es_setup_play_dead();
+
+	/* Secondary CPUs use the runtime #VC handler */
+	initial_vc_handler = (unsigned long)kernel_exc_vmm_communication;
+}
+
+static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt)
+{
+	int trapnr = ctxt->fi.vector;
+
+	if (trapnr == X86_TRAP_PF)
+		native_write_cr2(ctxt->fi.cr2);
+
+	ctxt->regs->orig_ax = ctxt->fi.error_code;
+	do_early_exception(ctxt->regs, trapnr);
+}
+
+static long *vc_insn_get_rm(struct es_em_ctxt *ctxt)
+{
+	long *reg_array;
+	int offset;
+
+	reg_array = (long *)ctxt->regs;
+	offset    = insn_get_modrm_rm_off(&ctxt->insn, ctxt->regs);
+
+	if (offset < 0)
+		return NULL;
+
+	offset /= sizeof(long);
+
+	return reg_array + offset;
+}
+static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
+				 unsigned int bytes, bool read)
+{
+	u64 exit_code, exit_info_1, exit_info_2;
+	unsigned long ghcb_pa = __pa(ghcb);
+	enum es_result res;
+	phys_addr_t paddr;
+	void __user *ref;
+
+	ref = insn_get_addr_ref(&ctxt->insn, ctxt->regs);
+	if (ref == (void __user *)-1L)
+		return ES_UNSUPPORTED;
+
+	exit_code = read ? SVM_VMGEXIT_MMIO_READ : SVM_VMGEXIT_MMIO_WRITE;
+
+	res = vc_slow_virt_to_phys(ghcb, ctxt, (unsigned long)ref, &paddr);
+	if (res != ES_OK) {
+		if (res == ES_EXCEPTION && !read)
+			ctxt->fi.error_code |= X86_PF_WRITE;
+
+		return res;
+	}
+
+	exit_info_1 = paddr;
+	/* Can never be greater than 8 */
+	exit_info_2 = bytes;
+
+	ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer));
+
+	return sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, exit_info_1, exit_info_2);
+}
+
+/*
+ * The MOVS instruction has two memory operands, which raises the
+ * problem that it is not known whether the access to the source or the
+ * destination caused the #VC exception (and hence whether an MMIO read
+ * or write operation needs to be emulated).
+ *
+ * Instead of playing games with walking page-tables and trying to guess
+ * whether the source or destination is an MMIO range, split the move
+ * into two operations, a read and a write with only one memory operand.
+ * This will cause a nested #VC exception on the MMIO address which can
+ * then be handled.
+ *
+ * This implementation has the benefit that it also supports MOVS where
+ * source _and_ destination are MMIO regions.
+ *
+ * It will slow MOVS on MMIO down a lot, but in SEV-ES guests it is a
+ * rare operation. If it turns out to be a performance problem the split
+ * operations can be moved to memcpy_fromio() and memcpy_toio().
+ */
+static enum es_result vc_handle_mmio_movs(struct es_em_ctxt *ctxt,
+					  unsigned int bytes)
+{
+	unsigned long ds_base, es_base;
+	unsigned char *src, *dst;
+	unsigned char buffer[8];
+	enum es_result ret;
+	bool rep;
+	int off;
+
+	ds_base = insn_get_seg_base(ctxt->regs, INAT_SEG_REG_DS);
+	es_base = insn_get_seg_base(ctxt->regs, INAT_SEG_REG_ES);
+
+	if (ds_base == -1L || es_base == -1L) {
+		ctxt->fi.vector = X86_TRAP_GP;
+		ctxt->fi.error_code = 0;
+		return ES_EXCEPTION;
+	}
+
+	src = ds_base + (unsigned char *)ctxt->regs->si;
+	dst = es_base + (unsigned char *)ctxt->regs->di;
+
+	ret = vc_read_mem(ctxt, src, buffer, bytes);
+	if (ret != ES_OK)
+		return ret;
+
+	ret = vc_write_mem(ctxt, dst, buffer, bytes);
+	if (ret != ES_OK)
+		return ret;
+
+	if (ctxt->regs->flags & X86_EFLAGS_DF)
+		off = -bytes;
+	else
+		off =  bytes;
+
+	ctxt->regs->si += off;
+	ctxt->regs->di += off;
+
+	rep = insn_has_rep_prefix(&ctxt->insn);
+	if (rep)
+		ctxt->regs->cx -= 1;
+
+	if (!rep || ctxt->regs->cx == 0)
+		return ES_OK;
+	else
+		return ES_RETRY;
+}
+
+static enum es_result vc_handle_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
+{
+	struct insn *insn = &ctxt->insn;
+	enum insn_mmio_type mmio;
+	unsigned int bytes = 0;
+	enum es_result ret;
+	u8 sign_byte;
+	long *reg_data;
+
+	mmio = insn_decode_mmio(insn, &bytes);
+	if (mmio == INSN_MMIO_DECODE_FAILED)
+		return ES_DECODE_FAILED;
+
+	if (mmio != INSN_MMIO_WRITE_IMM && mmio != INSN_MMIO_MOVS) {
+		reg_data = insn_get_modrm_reg_ptr(insn, ctxt->regs);
+		if (!reg_data)
+			return ES_DECODE_FAILED;
+	}
+
+	if (user_mode(ctxt->regs))
+		return ES_UNSUPPORTED;
+
+	switch (mmio) {
+	case INSN_MMIO_WRITE:
+		memcpy(ghcb->shared_buffer, reg_data, bytes);
+		ret = vc_do_mmio(ghcb, ctxt, bytes, false);
+		break;
+	case INSN_MMIO_WRITE_IMM:
+		memcpy(ghcb->shared_buffer, insn->immediate1.bytes, bytes);
+		ret = vc_do_mmio(ghcb, ctxt, bytes, false);
+		break;
+	case INSN_MMIO_READ:
+		ret = vc_do_mmio(ghcb, ctxt, bytes, true);
+		if (ret)
+			break;
+
+		/* Zero-extend for 32-bit operation */
+		if (bytes == 4)
+			*reg_data = 0;
+
+		memcpy(reg_data, ghcb->shared_buffer, bytes);
+		break;
+	case INSN_MMIO_READ_ZERO_EXTEND:
+		ret = vc_do_mmio(ghcb, ctxt, bytes, true);
+		if (ret)
+			break;
+
+		/* Zero extend based on operand size */
+		memset(reg_data, 0, insn->opnd_bytes);
+		memcpy(reg_data, ghcb->shared_buffer, bytes);
+		break;
+	case INSN_MMIO_READ_SIGN_EXTEND:
+		ret = vc_do_mmio(ghcb, ctxt, bytes, true);
+		if (ret)
+			break;
+
+		if (bytes == 1) {
+			u8 *val = (u8 *)ghcb->shared_buffer;
+
+			sign_byte = (*val & 0x80) ? 0xff : 0x00;
+		} else {
+			u16 *val = (u16 *)ghcb->shared_buffer;
+
+			sign_byte = (*val & 0x8000) ? 0xff : 0x00;
+		}
+
+		/* Sign extend based on operand size */
+		memset(reg_data, sign_byte, insn->opnd_bytes);
+		memcpy(reg_data, ghcb->shared_buffer, bytes);
+		break;
+	case INSN_MMIO_MOVS:
+		ret = vc_handle_mmio_movs(ctxt, bytes);
+		break;
+	default:
+		ret = ES_UNSUPPORTED;
+		break;
+	}
+
+	return ret;
+}
+
+static enum es_result vc_handle_dr7_write(struct ghcb *ghcb,
+					  struct es_em_ctxt *ctxt)
+{
+	struct sev_es_runtime_data *data = this_cpu_read(runtime_data);
+	long val, *reg = vc_insn_get_rm(ctxt);
+	enum es_result ret;
+
+	if (sev_status & MSR_AMD64_SNP_DEBUG_SWAP)
+		return ES_VMM_ERROR;
+
+	if (!reg)
+		return ES_DECODE_FAILED;
+
+	val = *reg;
+
+	/* Upper 32 bits must be written as zeroes */
+	if (val >> 32) {
+		ctxt->fi.vector = X86_TRAP_GP;
+		ctxt->fi.error_code = 0;
+		return ES_EXCEPTION;
+	}
+
+	/* Clear out other reserved bits and set bit 10 */
+	val = (val & 0xffff23ffL) | BIT(10);
+
+	/* Early non-zero writes to DR7 are not supported */
+	if (!data && (val & ~DR7_RESET_VALUE))
+		return ES_UNSUPPORTED;
+
+	/* Using a value of 0 for ExitInfo1 means RAX holds the value */
+	ghcb_set_rax(ghcb, val);
+	ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WRITE_DR7, 0, 0);
+	if (ret != ES_OK)
+		return ret;
+
+	if (data)
+		data->dr7 = val;
+
+	return ES_OK;
+}
+
+static enum es_result vc_handle_dr7_read(struct ghcb *ghcb,
+					 struct es_em_ctxt *ctxt)
+{
+	struct sev_es_runtime_data *data = this_cpu_read(runtime_data);
+	long *reg = vc_insn_get_rm(ctxt);
+
+	if (sev_status & MSR_AMD64_SNP_DEBUG_SWAP)
+		return ES_VMM_ERROR;
+
+	if (!reg)
+		return ES_DECODE_FAILED;
+
+	if (data)
+		*reg = data->dr7;
+	else
+		*reg = DR7_RESET_VALUE;
+
+	return ES_OK;
+}
+
+static enum es_result vc_handle_wbinvd(struct ghcb *ghcb,
+				       struct es_em_ctxt *ctxt)
+{
+	return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0);
+}
+
+static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
+{
+	enum es_result ret;
+
+	ghcb_set_rcx(ghcb, ctxt->regs->cx);
+
+	ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDPMC, 0, 0);
+	if (ret != ES_OK)
+		return ret;
+
+	if (!(ghcb_rax_is_valid(ghcb) && ghcb_rdx_is_valid(ghcb)))
+		return ES_VMM_ERROR;
+
+	ctxt->regs->ax = ghcb->save.rax;
+	ctxt->regs->dx = ghcb->save.rdx;
+
+	return ES_OK;
+}
+
+static enum es_result vc_handle_monitor(struct ghcb *ghcb,
+					struct es_em_ctxt *ctxt)
+{
+	/*
+	 * Treat it as a NOP and do not leak a physical address to the
+	 * hypervisor.
+	 */
+	return ES_OK;
+}
+
+static enum es_result vc_handle_mwait(struct ghcb *ghcb,
+				      struct es_em_ctxt *ctxt)
+{
+	/* Treat the same as MONITOR/MONITORX */
+	return ES_OK;
+}
+
+static enum es_result vc_handle_vmmcall(struct ghcb *ghcb,
+					struct es_em_ctxt *ctxt)
+{
+	enum es_result ret;
+
+	ghcb_set_rax(ghcb, ctxt->regs->ax);
+	ghcb_set_cpl(ghcb, user_mode(ctxt->regs) ? 3 : 0);
+
+	if (x86_platform.hyper.sev_es_hcall_prepare)
+		x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs);
+
+	ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0);
+	if (ret != ES_OK)
+		return ret;
+
+	if (!ghcb_rax_is_valid(ghcb))
+		return ES_VMM_ERROR;
+
+	ctxt->regs->ax = ghcb->save.rax;
+
+	/*
+	 * Call sev_es_hcall_finish() after regs->ax is already set.
+	 * This allows the hypervisor handler to overwrite it again if
+	 * necessary.
+	 */
+	if (x86_platform.hyper.sev_es_hcall_finish &&
+	    !x86_platform.hyper.sev_es_hcall_finish(ghcb, ctxt->regs))
+		return ES_VMM_ERROR;
+
+	return ES_OK;
+}
+
+static enum es_result vc_handle_trap_ac(struct ghcb *ghcb,
+					struct es_em_ctxt *ctxt)
+{
+	/*
+	 * Calling ecx_alignment_check() directly does not work, because it
+	 * enables IRQs and the GHCB is active. Forward the exception and call
+	 * it later from vc_forward_exception().
+	 */
+	ctxt->fi.vector = X86_TRAP_AC;
+	ctxt->fi.error_code = 0;
+	return ES_EXCEPTION;
+}
+
+static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
+					 struct ghcb *ghcb,
+					 unsigned long exit_code)
+{
+	enum es_result result;
+
+	switch (exit_code) {
+	case SVM_EXIT_READ_DR7:
+		result = vc_handle_dr7_read(ghcb, ctxt);
+		break;
+	case SVM_EXIT_WRITE_DR7:
+		result = vc_handle_dr7_write(ghcb, ctxt);
+		break;
+	case SVM_EXIT_EXCP_BASE + X86_TRAP_AC:
+		result = vc_handle_trap_ac(ghcb, ctxt);
+		break;
+	case SVM_EXIT_RDTSC:
+	case SVM_EXIT_RDTSCP:
+		result = vc_handle_rdtsc(ghcb, ctxt, exit_code);
+		break;
+	case SVM_EXIT_RDPMC:
+		result = vc_handle_rdpmc(ghcb, ctxt);
+		break;
+	case SVM_EXIT_INVD:
+		pr_err_ratelimited("#VC exception for INVD??? Seriously???\n");
+		result = ES_UNSUPPORTED;
+		break;
+	case SVM_EXIT_CPUID:
+		result = vc_handle_cpuid(ghcb, ctxt);
+		break;
+	case SVM_EXIT_IOIO:
+		result = vc_handle_ioio(ghcb, ctxt);
+		break;
+	case SVM_EXIT_MSR:
+		result = vc_handle_msr(ghcb, ctxt);
+		break;
+	case SVM_EXIT_VMMCALL:
+		result = vc_handle_vmmcall(ghcb, ctxt);
+		break;
+	case SVM_EXIT_WBINVD:
+		result = vc_handle_wbinvd(ghcb, ctxt);
+		break;
+	case SVM_EXIT_MONITOR:
+		result = vc_handle_monitor(ghcb, ctxt);
+		break;
+	case SVM_EXIT_MWAIT:
+		result = vc_handle_mwait(ghcb, ctxt);
+		break;
+	case SVM_EXIT_NPF:
+		result = vc_handle_mmio(ghcb, ctxt);
+		break;
+	default:
+		/*
+		 * Unexpected #VC exception
+		 */
+		result = ES_UNSUPPORTED;
+	}
+
+	return result;
+}
+
+static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt)
+{
+	long error_code = ctxt->fi.error_code;
+	int trapnr = ctxt->fi.vector;
+
+	ctxt->regs->orig_ax = ctxt->fi.error_code;
+
+	switch (trapnr) {
+	case X86_TRAP_GP:
+		exc_general_protection(ctxt->regs, error_code);
+		break;
+	case X86_TRAP_UD:
+		exc_invalid_op(ctxt->regs);
+		break;
+	case X86_TRAP_PF:
+		write_cr2(ctxt->fi.cr2);
+		exc_page_fault(ctxt->regs, error_code);
+		break;
+	case X86_TRAP_AC:
+		exc_alignment_check(ctxt->regs, error_code);
+		break;
+	default:
+		pr_emerg("Unsupported exception in #VC instruction emulation - can't continue\n");
+		BUG();
+	}
+}
+
+static __always_inline bool is_vc2_stack(unsigned long sp)
+{
+	return (sp >= __this_cpu_ist_bottom_va(VC2) && sp < __this_cpu_ist_top_va(VC2));
+}
+
+static __always_inline bool vc_from_invalid_context(struct pt_regs *regs)
+{
+	unsigned long sp, prev_sp;
+
+	sp      = (unsigned long)regs;
+	prev_sp = regs->sp;
+
+	/*
+	 * If the code was already executing on the VC2 stack when the #VC
+	 * happened, let it proceed to the normal handling routine. This way the
+	 * code executing on the VC2 stack can cause #VC exceptions to get handled.
+	 */
+	return is_vc2_stack(sp) && !is_vc2_stack(prev_sp);
+}
+
+static bool vc_raw_handle_exception(struct pt_regs *regs, unsigned long error_code)
+{
+	struct ghcb_state state;
+	struct es_em_ctxt ctxt;
+	enum es_result result;
+	struct ghcb *ghcb;
+	bool ret = true;
+
+	ghcb = __sev_get_ghcb(&state);
+
+	vc_ghcb_invalidate(ghcb);
+	result = vc_init_em_ctxt(&ctxt, regs, error_code);
+
+	if (result == ES_OK)
+		result = vc_handle_exitcode(&ctxt, ghcb, error_code);
+
+	__sev_put_ghcb(&state);
+
+	/* Done - now check the result */
+	switch (result) {
+	case ES_OK:
+		vc_finish_insn(&ctxt);
+		break;
+	case ES_UNSUPPORTED:
+		pr_err_ratelimited("Unsupported exit-code 0x%02lx in #VC exception (IP: 0x%lx)\n",
+				   error_code, regs->ip);
+		ret = false;
+		break;
+	case ES_VMM_ERROR:
+		pr_err_ratelimited("Failure in communication with VMM (exit-code 0x%02lx IP: 0x%lx)\n",
+				   error_code, regs->ip);
+		ret = false;
+		break;
+	case ES_DECODE_FAILED:
+		pr_err_ratelimited("Failed to decode instruction (exit-code 0x%02lx IP: 0x%lx)\n",
+				   error_code, regs->ip);
+		ret = false;
+		break;
+	case ES_EXCEPTION:
+		vc_forward_exception(&ctxt);
+		break;
+	case ES_RETRY:
+		/* Nothing to do */
+		break;
+	default:
+		pr_emerg("Unknown result in %s():%d\n", __func__, result);
+		/*
+		 * Emulating the instruction which caused the #VC exception
+		 * failed - can't continue so print debug information
+		 */
+		BUG();
+	}
+
+	return ret;
+}
+
+static __always_inline bool vc_is_db(unsigned long error_code)
+{
+	return error_code == SVM_EXIT_EXCP_BASE + X86_TRAP_DB;
+}
+
+/*
+ * Runtime #VC exception handler when raised from kernel mode. Runs in NMI mode
+ * and will panic when an error happens.
+ */
+DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
+{
+	irqentry_state_t irq_state;
+
+	/*
+	 * With the current implementation it is always possible to switch to a
+	 * safe stack because #VC exceptions only happen at known places, like
+	 * intercepted instructions or accesses to MMIO areas/IO ports. They can
+	 * also happen with code instrumentation when the hypervisor intercepts
+	 * #DB, but the critical paths are forbidden to be instrumented, so #DB
+	 * exceptions currently also only happen in safe places.
+	 *
+	 * But keep this here in case the noinstr annotations are violated due
+	 * to bug elsewhere.
+	 */
+	if (unlikely(vc_from_invalid_context(regs))) {
+		instrumentation_begin();
+		panic("Can't handle #VC exception from unsupported context\n");
+		instrumentation_end();
+	}
+
+	/*
+	 * Handle #DB before calling into !noinstr code to avoid recursive #DB.
+	 */
+	if (vc_is_db(error_code)) {
+		exc_debug(regs);
+		return;
+	}
+
+	irq_state = irqentry_nmi_enter(regs);
+
+	instrumentation_begin();
+
+	if (!vc_raw_handle_exception(regs, error_code)) {
+		/* Show some debug info */
+		show_regs(regs);
+
+		/* Ask hypervisor to sev_es_terminate */
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
+
+		/* If that fails and we get here - just panic */
+		panic("Returned from Terminate-Request to Hypervisor\n");
+	}
+
+	instrumentation_end();
+	irqentry_nmi_exit(regs, irq_state);
+}
+
+/*
+ * Runtime #VC exception handler when raised from user mode. Runs in IRQ mode
+ * and will kill the current task with SIGBUS when an error happens.
+ */
+DEFINE_IDTENTRY_VC_USER(exc_vmm_communication)
+{
+	/*
+	 * Handle #DB before calling into !noinstr code to avoid recursive #DB.
+	 */
+	if (vc_is_db(error_code)) {
+		noist_exc_debug(regs);
+		return;
+	}
+
+	irqentry_enter_from_user_mode(regs);
+	instrumentation_begin();
+
+	if (!vc_raw_handle_exception(regs, error_code)) {
+		/*
+		 * Do not kill the machine if user-space triggered the
+		 * exception. Send SIGBUS instead and let user-space deal with
+		 * it.
+		 */
+		force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)0);
+	}
+
+	instrumentation_end();
+	irqentry_exit_to_user_mode(regs);
+}
+
+bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
+{
+	unsigned long exit_code = regs->orig_ax;
+	struct es_em_ctxt ctxt;
+	enum es_result result;
+
+	vc_ghcb_invalidate(boot_ghcb);
+
+	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
+	if (result == ES_OK)
+		result = vc_handle_exitcode(&ctxt, boot_ghcb, exit_code);
+
+	/* Done - now check the result */
+	switch (result) {
+	case ES_OK:
+		vc_finish_insn(&ctxt);
+		break;
+	case ES_UNSUPPORTED:
+		early_printk("PANIC: Unsupported exit-code 0x%02lx in early #VC exception (IP: 0x%lx)\n",
+				exit_code, regs->ip);
+		goto fail;
+	case ES_VMM_ERROR:
+		early_printk("PANIC: Failure in communication with VMM (exit-code 0x%02lx IP: 0x%lx)\n",
+				exit_code, regs->ip);
+		goto fail;
+	case ES_DECODE_FAILED:
+		early_printk("PANIC: Failed to decode instruction (exit-code 0x%02lx IP: 0x%lx)\n",
+				exit_code, regs->ip);
+		goto fail;
+	case ES_EXCEPTION:
+		vc_early_forward_exception(&ctxt);
+		break;
+	case ES_RETRY:
+		/* Nothing to do */
+		break;
+	default:
+		BUG();
+	}
+
+	return true;
+
+fail:
+	show_regs(regs);
+
+	sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
+}
+
+/*
+ * 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 __init struct cc_blob_sev_info *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)
+		snp_abort();
+
+	return cc_info;
+}
+
+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;
+
+	setup_cpuid_table(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;
+}
+
+void __init __noreturn snp_abort(void)
+{
+	sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+}
+
+static void dump_cpuid_table(void)
+{
+	const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
+	int i = 0;
+
+	pr_info("count=%d reserved=0x%x reserved2=0x%llx\n",
+		cpuid_table->count, cpuid_table->__reserved1, cpuid_table->__reserved2);
+
+	for (i = 0; i < SNP_CPUID_COUNT_MAX; i++) {
+		const struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
+
+		pr_info("index=%3d fn=0x%08x subfn=0x%08x: eax=0x%08x ebx=0x%08x ecx=0x%08x edx=0x%08x xcr0_in=0x%016llx xss_in=0x%016llx reserved=0x%016llx\n",
+			i, fn->eax_in, fn->ecx_in, fn->eax, fn->ebx, fn->ecx,
+			fn->edx, fn->xcr0_in, fn->xss_in, fn->__reserved);
+	}
+}
+
+/*
+ * It is useful from an auditing/testing perspective to provide an easy way
+ * for the guest owner to know that the CPUID table has been initialized as
+ * expected, but that initialization happens too early in boot to print any
+ * sort of indicator, and there's not really any other good place to do it,
+ * so do it here.
+ */
+static int __init report_cpuid_table(void)
+{
+	const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
+
+	if (!cpuid_table->count)
+		return 0;
+
+	pr_info("Using SNP CPUID table, %d entries present.\n",
+		cpuid_table->count);
+
+	if (sev_cfg.debug)
+		dump_cpuid_table();
+
+	return 0;
+}
+arch_initcall(report_cpuid_table);
+
+static int __init init_sev_config(char *str)
+{
+	char *s;
+
+	while ((s = strsep(&str, ","))) {
+		if (!strcmp(s, "debug")) {
+			sev_cfg.debug = true;
+			continue;
+		}
+
+		pr_info("SEV command-line option '%s' was not recognized\n", s);
+	}
+
+	return 1;
+}
+__setup("sev=", init_sev_config);
+
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
+{
+	struct ghcb_state state;
+	struct es_em_ctxt ctxt;
+	unsigned long flags;
+	struct ghcb *ghcb;
+	int ret;
+
+	rio->exitinfo2 = SEV_RET_NO_FW_CALL;
+
+	/*
+	 * __sev_get_ghcb() needs to run with IRQs disabled because it is using
+	 * a per-CPU GHCB.
+	 */
+	local_irq_save(flags);
+
+	ghcb = __sev_get_ghcb(&state);
+	if (!ghcb) {
+		ret = -EIO;
+		goto e_restore_irq;
+	}
+
+	vc_ghcb_invalidate(ghcb);
+
+	if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+		ghcb_set_rax(ghcb, input->data_gpa);
+		ghcb_set_rbx(ghcb, input->data_npages);
+	}
+
+	ret = sev_es_ghcb_hv_call(ghcb, &ctxt, exit_code, input->req_gpa, input->resp_gpa);
+	if (ret)
+		goto e_put;
+
+	rio->exitinfo2 = ghcb->save.sw_exit_info_2;
+	switch (rio->exitinfo2) {
+	case 0:
+		break;
+
+	case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_BUSY):
+		ret = -EAGAIN;
+		break;
+
+	case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN):
+		/* Number of expected pages are returned in RBX */
+		if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+			input->data_npages = ghcb_get_rbx(ghcb);
+			ret = -ENOSPC;
+			break;
+		}
+		fallthrough;
+	default:
+		ret = -EIO;
+		break;
+	}
+
+e_put:
+	__sev_put_ghcb(&state);
+e_restore_irq:
+	local_irq_restore(flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snp_issue_guest_request);
+
+static struct platform_device sev_guest_device = {
+	.name		= "sev-guest",
+	.id		= -1,
+};
+
+static int __init snp_init_platform_device(void)
+{
+	struct sev_guest_platform_data data;
+	u64 gpa;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return -ENODEV;
+
+	gpa = get_secrets_page();
+	if (!gpa)
+		return -ENODEV;
+
+	data.secrets_gpa = gpa;
+	if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
+		return -ENODEV;
+
+	if (platform_device_register(&sev_guest_device))
+		return -ENODEV;
+
+	pr_info("SNP guest platform device initialized.\n");
+	return 0;
+}
+device_initcall(snp_init_platform_device);