1 files changed, 823 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
new file mode 100644
index 000000000000..90a1ca939627
--- /dev/null
+++ b/arch/x86/kvm/svm/nested.c
@@ -0,0 +1,823 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel-based Virtual Machine driver for Linux
+ *
+ * AMD SVM support
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affiliates.
+ *
+ * Authors:
+ *   Yaniv Kamay  <yaniv@qumranet.com>
+ *   Avi Kivity   <avi@qumranet.com>
+ */
+
+#define pr_fmt(fmt) "SVM: " fmt
+
+#include <linux/kvm_types.h>
+#include <linux/kvm_host.h>
+#include <linux/kernel.h>
+
+#include <asm/msr-index.h>
+
+#include "kvm_emulate.h"
+#include "trace.h"
+#include "mmu.h"
+#include "x86.h"
+#include "svm.h"
+
+static void nested_svm_inject_npf_exit(struct kvm_vcpu *vcpu,
+				       struct x86_exception *fault)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (svm->vmcb->control.exit_code != SVM_EXIT_NPF) {
+		/*
+		 * TODO: track the cause of the nested page fault, and
+		 * correctly fill in the high bits of exit_info_1.
+		 */
+		svm->vmcb->control.exit_code = SVM_EXIT_NPF;
+		svm->vmcb->control.exit_code_hi = 0;
+		svm->vmcb->control.exit_info_1 = (1ULL << 32);
+		svm->vmcb->control.exit_info_2 = fault->address;
+	}
+
+	svm->vmcb->control.exit_info_1 &= ~0xffffffffULL;
+	svm->vmcb->control.exit_info_1 |= fault->error_code;
+
+	/*
+	 * The present bit is always zero for page structure faults on real
+	 * hardware.
+	 */
+	if (svm->vmcb->control.exit_info_1 & (2ULL << 32))
+		svm->vmcb->control.exit_info_1 &= ~1;
+
+	nested_svm_vmexit(svm);
+}
+
+static u64 nested_svm_get_tdp_pdptr(struct kvm_vcpu *vcpu, int index)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	u64 cr3 = svm->nested.nested_cr3;
+	u64 pdpte;
+	int ret;
+
+	ret = kvm_vcpu_read_guest_page(vcpu, gpa_to_gfn(__sme_clr(cr3)), &pdpte,
+				       offset_in_page(cr3) + index * 8, 8);
+	if (ret)
+		return 0;
+	return pdpte;
+}
+
+static unsigned long nested_svm_get_tdp_cr3(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	return svm->nested.nested_cr3;
+}
+
+static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
+{
+	WARN_ON(mmu_is_nested(vcpu));
+
+	vcpu->arch.mmu = &vcpu->arch.guest_mmu;
+	kvm_init_shadow_mmu(vcpu);
+	vcpu->arch.mmu->get_guest_pgd     = nested_svm_get_tdp_cr3;
+	vcpu->arch.mmu->get_pdptr         = nested_svm_get_tdp_pdptr;
+	vcpu->arch.mmu->inject_page_fault = nested_svm_inject_npf_exit;
+	vcpu->arch.mmu->shadow_root_level = kvm_x86_ops.get_tdp_level(vcpu);
+	reset_shadow_zero_bits_mask(vcpu, vcpu->arch.mmu);
+	vcpu->arch.walk_mmu              = &vcpu->arch.nested_mmu;
+}
+
+static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.mmu = &vcpu->arch.root_mmu;
+	vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
+}
+
+void recalc_intercepts(struct vcpu_svm *svm)
+{
+	struct vmcb_control_area *c, *h;
+	struct nested_state *g;
+
+	mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
+
+	if (!is_guest_mode(&svm->vcpu))
+		return;
+
+	c = &svm->vmcb->control;
+	h = &svm->nested.hsave->control;
+	g = &svm->nested;
+
+	c->intercept_cr = h->intercept_cr;
+	c->intercept_dr = h->intercept_dr;
+	c->intercept_exceptions = h->intercept_exceptions;
+	c->intercept = h->intercept;
+
+	if (svm->vcpu.arch.hflags & HF_VINTR_MASK) {
+		/* We only want the cr8 intercept bits of L1 */
+		c->intercept_cr &= ~(1U << INTERCEPT_CR8_READ);
+		c->intercept_cr &= ~(1U << INTERCEPT_CR8_WRITE);
+
+		/*
+		 * Once running L2 with HF_VINTR_MASK, EFLAGS.IF does not
+		 * affect any interrupt we may want to inject; therefore,
+		 * interrupt window vmexits are irrelevant to L0.
+		 */
+		c->intercept &= ~(1ULL << INTERCEPT_VINTR);
+	}
+
+	/* We don't want to see VMMCALLs from a nested guest */
+	c->intercept &= ~(1ULL << INTERCEPT_VMMCALL);
+
+	c->intercept_cr |= g->intercept_cr;
+	c->intercept_dr |= g->intercept_dr;
+	c->intercept_exceptions |= g->intercept_exceptions;
+	c->intercept |= g->intercept;
+}
+
+static void copy_vmcb_control_area(struct vmcb *dst_vmcb, struct vmcb *from_vmcb)
+{
+	struct vmcb_control_area *dst  = &dst_vmcb->control;
+	struct vmcb_control_area *from = &from_vmcb->control;
+
+	dst->intercept_cr         = from->intercept_cr;
+	dst->intercept_dr         = from->intercept_dr;
+	dst->intercept_exceptions = from->intercept_exceptions;
+	dst->intercept            = from->intercept;
+	dst->iopm_base_pa         = from->iopm_base_pa;
+	dst->msrpm_base_pa        = from->msrpm_base_pa;
+	dst->tsc_offset           = from->tsc_offset;
+	dst->asid                 = from->asid;
+	dst->tlb_ctl              = from->tlb_ctl;
+	dst->int_ctl              = from->int_ctl;
+	dst->int_vector           = from->int_vector;
+	dst->int_state            = from->int_state;
+	dst->exit_code            = from->exit_code;
+	dst->exit_code_hi         = from->exit_code_hi;
+	dst->exit_info_1          = from->exit_info_1;
+	dst->exit_info_2          = from->exit_info_2;
+	dst->exit_int_info        = from->exit_int_info;
+	dst->exit_int_info_err    = from->exit_int_info_err;
+	dst->nested_ctl           = from->nested_ctl;
+	dst->event_inj            = from->event_inj;
+	dst->event_inj_err        = from->event_inj_err;
+	dst->nested_cr3           = from->nested_cr3;
+	dst->virt_ext              = from->virt_ext;
+	dst->pause_filter_count   = from->pause_filter_count;
+	dst->pause_filter_thresh  = from->pause_filter_thresh;
+}
+
+static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
+{
+	/*
+	 * This function merges the msr permission bitmaps of kvm and the
+	 * nested vmcb. It is optimized in that it only merges the parts where
+	 * the kvm msr permission bitmap may contain zero bits
+	 */
+	int i;
+
+	if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
+		return true;
+
+	for (i = 0; i < MSRPM_OFFSETS; i++) {
+		u32 value, p;
+		u64 offset;
+
+		if (msrpm_offsets[i] == 0xffffffff)
+			break;
+
+		p      = msrpm_offsets[i];
+		offset = svm->nested.vmcb_msrpm + (p * 4);
+
+		if (kvm_vcpu_read_guest(&svm->vcpu, offset, &value, 4))
+			return false;
+
+		svm->nested.msrpm[p] = svm->msrpm[p] | value;
+	}
+
+	svm->vmcb->control.msrpm_base_pa = __sme_set(__pa(svm->nested.msrpm));
+
+	return true;
+}
+
+static bool nested_vmcb_checks(struct vmcb *vmcb)
+{
+	if ((vmcb->save.efer & EFER_SVME) == 0)
+		return false;
+
+	if ((vmcb->control.intercept & (1ULL << INTERCEPT_VMRUN)) == 0)
+		return false;
+
+	if (vmcb->control.asid == 0)
+		return false;
+
+	if ((vmcb->control.nested_ctl & SVM_NESTED_CTL_NP_ENABLE) &&
+	    !npt_enabled)
+		return false;
+
+	return true;
+}
+
+void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
+			  struct vmcb *nested_vmcb, struct kvm_host_map *map)
+{
+	bool evaluate_pending_interrupts =
+		is_intercept(svm, INTERCEPT_VINTR) ||
+		is_intercept(svm, INTERCEPT_IRET);
+
+	if (kvm_get_rflags(&svm->vcpu) & X86_EFLAGS_IF)
+		svm->vcpu.arch.hflags |= HF_HIF_MASK;
+	else
+		svm->vcpu.arch.hflags &= ~HF_HIF_MASK;
+
+	if (nested_vmcb->control.nested_ctl & SVM_NESTED_CTL_NP_ENABLE) {
+		svm->nested.nested_cr3 = nested_vmcb->control.nested_cr3;
+		nested_svm_init_mmu_context(&svm->vcpu);
+	}
+
+	/* Load the nested guest state */
+	svm->vmcb->save.es = nested_vmcb->save.es;
+	svm->vmcb->save.cs = nested_vmcb->save.cs;
+	svm->vmcb->save.ss = nested_vmcb->save.ss;
+	svm->vmcb->save.ds = nested_vmcb->save.ds;
+	svm->vmcb->save.gdtr = nested_vmcb->save.gdtr;
+	svm->vmcb->save.idtr = nested_vmcb->save.idtr;
+	kvm_set_rflags(&svm->vcpu, nested_vmcb->save.rflags);
+	svm_set_efer(&svm->vcpu, nested_vmcb->save.efer);
+	svm_set_cr0(&svm->vcpu, nested_vmcb->save.cr0);
+	svm_set_cr4(&svm->vcpu, nested_vmcb->save.cr4);
+	if (npt_enabled) {
+		svm->vmcb->save.cr3 = nested_vmcb->save.cr3;
+		svm->vcpu.arch.cr3 = nested_vmcb->save.cr3;
+	} else
+		(void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
+
+	/* Guest paging mode is active - reset mmu */
+	kvm_mmu_reset_context(&svm->vcpu);
+
+	svm->vmcb->save.cr2 = svm->vcpu.arch.cr2 = nested_vmcb->save.cr2;
+	kvm_rax_write(&svm->vcpu, nested_vmcb->save.rax);
+	kvm_rsp_write(&svm->vcpu, nested_vmcb->save.rsp);
+	kvm_rip_write(&svm->vcpu, nested_vmcb->save.rip);
+
+	/* In case we don't even reach vcpu_run, the fields are not updated */
+	svm->vmcb->save.rax = nested_vmcb->save.rax;
+	svm->vmcb->save.rsp = nested_vmcb->save.rsp;
+	svm->vmcb->save.rip = nested_vmcb->save.rip;
+	svm->vmcb->save.dr7 = nested_vmcb->save.dr7;
+	svm->vmcb->save.dr6 = nested_vmcb->save.dr6;
+	svm->vmcb->save.cpl = nested_vmcb->save.cpl;
+
+	svm->nested.vmcb_msrpm = nested_vmcb->control.msrpm_base_pa & ~0x0fffULL;
+	svm->nested.vmcb_iopm  = nested_vmcb->control.iopm_base_pa  & ~0x0fffULL;
+
+	/* cache intercepts */
+	svm->nested.intercept_cr         = nested_vmcb->control.intercept_cr;
+	svm->nested.intercept_dr         = nested_vmcb->control.intercept_dr;
+	svm->nested.intercept_exceptions = nested_vmcb->control.intercept_exceptions;
+	svm->nested.intercept            = nested_vmcb->control.intercept;
+
+	svm_flush_tlb(&svm->vcpu, true);
+	svm->vmcb->control.int_ctl = nested_vmcb->control.int_ctl | V_INTR_MASKING_MASK;
+	if (nested_vmcb->control.int_ctl & V_INTR_MASKING_MASK)
+		svm->vcpu.arch.hflags |= HF_VINTR_MASK;
+	else
+		svm->vcpu.arch.hflags &= ~HF_VINTR_MASK;
+
+	svm->vcpu.arch.tsc_offset += nested_vmcb->control.tsc_offset;
+	svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset;
+
+	svm->vmcb->control.virt_ext = nested_vmcb->control.virt_ext;
+	svm->vmcb->control.int_vector = nested_vmcb->control.int_vector;
+	svm->vmcb->control.int_state = nested_vmcb->control.int_state;
+	svm->vmcb->control.event_inj = nested_vmcb->control.event_inj;
+	svm->vmcb->control.event_inj_err = nested_vmcb->control.event_inj_err;
+
+	svm->vmcb->control.pause_filter_count =
+		nested_vmcb->control.pause_filter_count;
+	svm->vmcb->control.pause_filter_thresh =
+		nested_vmcb->control.pause_filter_thresh;
+
+	kvm_vcpu_unmap(&svm->vcpu, map, true);
+
+	/* Enter Guest-Mode */
+	enter_guest_mode(&svm->vcpu);
+
+	/*
+	 * Merge guest and host intercepts - must be called  with vcpu in
+	 * guest-mode to take affect here
+	 */
+	recalc_intercepts(svm);
+
+	svm->nested.vmcb = vmcb_gpa;
+
+	/*
+	 * If L1 had a pending IRQ/NMI before executing VMRUN,
+	 * which wasn't delivered because it was disallowed (e.g.
+	 * interrupts disabled), L0 needs to evaluate if this pending
+	 * event should cause an exit from L2 to L1 or be delivered
+	 * directly to L2.
+	 *
+	 * Usually this would be handled by the processor noticing an
+	 * IRQ/NMI window request.  However, VMRUN can unblock interrupts
+	 * by implicitly setting GIF, so force L0 to perform pending event
+	 * evaluation by requesting a KVM_REQ_EVENT.
+	 */
+	enable_gif(svm);
+	if (unlikely(evaluate_pending_interrupts))
+		kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
+
+	mark_all_dirty(svm->vmcb);
+}
+
+int nested_svm_vmrun(struct vcpu_svm *svm)
+{
+	int ret;
+	struct vmcb *nested_vmcb;
+	struct vmcb *hsave = svm->nested.hsave;
+	struct vmcb *vmcb = svm->vmcb;
+	struct kvm_host_map map;
+	u64 vmcb_gpa;
+
+	vmcb_gpa = svm->vmcb->save.rax;
+
+	ret = kvm_vcpu_map(&svm->vcpu, gpa_to_gfn(vmcb_gpa), &map);
+	if (ret == -EINVAL) {
+		kvm_inject_gp(&svm->vcpu, 0);
+		return 1;
+	} else if (ret) {
+		return kvm_skip_emulated_instruction(&svm->vcpu);
+	}
+
+	ret = kvm_skip_emulated_instruction(&svm->vcpu);
+
+	nested_vmcb = map.hva;
+
+	if (!nested_vmcb_checks(nested_vmcb)) {
+		nested_vmcb->control.exit_code    = SVM_EXIT_ERR;
+		nested_vmcb->control.exit_code_hi = 0;
+		nested_vmcb->control.exit_info_1  = 0;
+		nested_vmcb->control.exit_info_2  = 0;
+
+		kvm_vcpu_unmap(&svm->vcpu, &map, true);
+
+		return ret;
+	}
+
+	trace_kvm_nested_vmrun(svm->vmcb->save.rip, vmcb_gpa,
+			       nested_vmcb->save.rip,
+			       nested_vmcb->control.int_ctl,
+			       nested_vmcb->control.event_inj,
+			       nested_vmcb->control.nested_ctl);
+
+	trace_kvm_nested_intercepts(nested_vmcb->control.intercept_cr & 0xffff,
+				    nested_vmcb->control.intercept_cr >> 16,
+				    nested_vmcb->control.intercept_exceptions,
+				    nested_vmcb->control.intercept);
+
+	/* Clear internal status */
+	kvm_clear_exception_queue(&svm->vcpu);
+	kvm_clear_interrupt_queue(&svm->vcpu);
+
+	/*
+	 * Save the old vmcb, so we don't need to pick what we save, but can
+	 * restore everything when a VMEXIT occurs
+	 */
+	hsave->save.es     = vmcb->save.es;
+	hsave->save.cs     = vmcb->save.cs;
+	hsave->save.ss     = vmcb->save.ss;
+	hsave->save.ds     = vmcb->save.ds;
+	hsave->save.gdtr   = vmcb->save.gdtr;
+	hsave->save.idtr   = vmcb->save.idtr;
+	hsave->save.efer   = svm->vcpu.arch.efer;
+	hsave->save.cr0    = kvm_read_cr0(&svm->vcpu);
+	hsave->save.cr4    = svm->vcpu.arch.cr4;
+	hsave->save.rflags = kvm_get_rflags(&svm->vcpu);
+	hsave->save.rip    = kvm_rip_read(&svm->vcpu);
+	hsave->save.rsp    = vmcb->save.rsp;
+	hsave->save.rax    = vmcb->save.rax;
+	if (npt_enabled)
+		hsave->save.cr3    = vmcb->save.cr3;
+	else
+		hsave->save.cr3    = kvm_read_cr3(&svm->vcpu);
+
+	copy_vmcb_control_area(hsave, vmcb);
+
+	enter_svm_guest_mode(svm, vmcb_gpa, nested_vmcb, &map);
+
+	if (!nested_svm_vmrun_msrpm(svm)) {
+		svm->vmcb->control.exit_code    = SVM_EXIT_ERR;
+		svm->vmcb->control.exit_code_hi = 0;
+		svm->vmcb->control.exit_info_1  = 0;
+		svm->vmcb->control.exit_info_2  = 0;
+
+		nested_svm_vmexit(svm);
+	}
+
+	return ret;
+}
+
+void nested_svm_vmloadsave(struct vmcb *from_vmcb, struct vmcb *to_vmcb)
+{
+	to_vmcb->save.fs = from_vmcb->save.fs;
+	to_vmcb->save.gs = from_vmcb->save.gs;
+	to_vmcb->save.tr = from_vmcb->save.tr;
+	to_vmcb->save.ldtr = from_vmcb->save.ldtr;
+	to_vmcb->save.kernel_gs_base = from_vmcb->save.kernel_gs_base;
+	to_vmcb->save.star = from_vmcb->save.star;
+	to_vmcb->save.lstar = from_vmcb->save.lstar;
+	to_vmcb->save.cstar = from_vmcb->save.cstar;
+	to_vmcb->save.sfmask = from_vmcb->save.sfmask;
+	to_vmcb->save.sysenter_cs = from_vmcb->save.sysenter_cs;
+	to_vmcb->save.sysenter_esp = from_vmcb->save.sysenter_esp;
+	to_vmcb->save.sysenter_eip = from_vmcb->save.sysenter_eip;
+}
+
+int nested_svm_vmexit(struct vcpu_svm *svm)
+{
+	int rc;
+	struct vmcb *nested_vmcb;
+	struct vmcb *hsave = svm->nested.hsave;
+	struct vmcb *vmcb = svm->vmcb;
+	struct kvm_host_map map;
+
+	trace_kvm_nested_vmexit_inject(vmcb->control.exit_code,
+				       vmcb->control.exit_info_1,
+				       vmcb->control.exit_info_2,
+				       vmcb->control.exit_int_info,
+				       vmcb->control.exit_int_info_err,
+				       KVM_ISA_SVM);
+
+	rc = kvm_vcpu_map(&svm->vcpu, gpa_to_gfn(svm->nested.vmcb), &map);
+	if (rc) {
+		if (rc == -EINVAL)
+			kvm_inject_gp(&svm->vcpu, 0);
+		return 1;
+	}
+
+	nested_vmcb = map.hva;
+
+	/* Exit Guest-Mode */
+	leave_guest_mode(&svm->vcpu);
+	svm->nested.vmcb = 0;
+
+	/* Give the current vmcb to the guest */
+	disable_gif(svm);
+
+	nested_vmcb->save.es     = vmcb->save.es;
+	nested_vmcb->save.cs     = vmcb->save.cs;
+	nested_vmcb->save.ss     = vmcb->save.ss;
+	nested_vmcb->save.ds     = vmcb->save.ds;
+	nested_vmcb->save.gdtr   = vmcb->save.gdtr;
+	nested_vmcb->save.idtr   = vmcb->save.idtr;
+	nested_vmcb->save.efer   = svm->vcpu.arch.efer;
+	nested_vmcb->save.cr0    = kvm_read_cr0(&svm->vcpu);
+	nested_vmcb->save.cr3    = kvm_read_cr3(&svm->vcpu);
+	nested_vmcb->save.cr2    = vmcb->save.cr2;
+	nested_vmcb->save.cr4    = svm->vcpu.arch.cr4;
+	nested_vmcb->save.rflags = kvm_get_rflags(&svm->vcpu);
+	nested_vmcb->save.rip    = vmcb->save.rip;
+	nested_vmcb->save.rsp    = vmcb->save.rsp;
+	nested_vmcb->save.rax    = vmcb->save.rax;
+	nested_vmcb->save.dr7    = vmcb->save.dr7;
+	nested_vmcb->save.dr6    = vmcb->save.dr6;
+	nested_vmcb->save.cpl    = vmcb->save.cpl;
+
+	nested_vmcb->control.int_ctl           = vmcb->control.int_ctl;
+	nested_vmcb->control.int_vector        = vmcb->control.int_vector;
+	nested_vmcb->control.int_state         = vmcb->control.int_state;
+	nested_vmcb->control.exit_code         = vmcb->control.exit_code;
+	nested_vmcb->control.exit_code_hi      = vmcb->control.exit_code_hi;
+	nested_vmcb->control.exit_info_1       = vmcb->control.exit_info_1;
+	nested_vmcb->control.exit_info_2       = vmcb->control.exit_info_2;
+	nested_vmcb->control.exit_int_info     = vmcb->control.exit_int_info;
+	nested_vmcb->control.exit_int_info_err = vmcb->control.exit_int_info_err;
+
+	if (svm->nrips_enabled)
+		nested_vmcb->control.next_rip  = vmcb->control.next_rip;
+
+	/*
+	 * If we emulate a VMRUN/#VMEXIT in the same host #vmexit cycle we have
+	 * to make sure that we do not lose injected events. So check event_inj
+	 * here and copy it to exit_int_info if it is valid.
+	 * Exit_int_info and event_inj can't be both valid because the case
+	 * below only happens on a VMRUN instruction intercept which has
+	 * no valid exit_int_info set.
+	 */
+	if (vmcb->control.event_inj & SVM_EVTINJ_VALID) {
+		struct vmcb_control_area *nc = &nested_vmcb->control;
+
+		nc->exit_int_info     = vmcb->control.event_inj;
+		nc->exit_int_info_err = vmcb->control.event_inj_err;
+	}
+
+	nested_vmcb->control.tlb_ctl           = 0;
+	nested_vmcb->control.event_inj         = 0;
+	nested_vmcb->control.event_inj_err     = 0;
+
+	nested_vmcb->control.pause_filter_count =
+		svm->vmcb->control.pause_filter_count;
+	nested_vmcb->control.pause_filter_thresh =
+		svm->vmcb->control.pause_filter_thresh;
+
+	/* We always set V_INTR_MASKING and remember the old value in hflags */
+	if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK))
+		nested_vmcb->control.int_ctl &= ~V_INTR_MASKING_MASK;
+
+	/* Restore the original control entries */
+	copy_vmcb_control_area(vmcb, hsave);
+
+	svm->vcpu.arch.tsc_offset = svm->vmcb->control.tsc_offset;
+	kvm_clear_exception_queue(&svm->vcpu);
+	kvm_clear_interrupt_queue(&svm->vcpu);
+
+	svm->nested.nested_cr3 = 0;
+
+	/* Restore selected save entries */
+	svm->vmcb->save.es = hsave->save.es;
+	svm->vmcb->save.cs = hsave->save.cs;
+	svm->vmcb->save.ss = hsave->save.ss;
+	svm->vmcb->save.ds = hsave->save.ds;
+	svm->vmcb->save.gdtr = hsave->save.gdtr;
+	svm->vmcb->save.idtr = hsave->save.idtr;
+	kvm_set_rflags(&svm->vcpu, hsave->save.rflags);
+	svm_set_efer(&svm->vcpu, hsave->save.efer);
+	svm_set_cr0(&svm->vcpu, hsave->save.cr0 | X86_CR0_PE);
+	svm_set_cr4(&svm->vcpu, hsave->save.cr4);
+	if (npt_enabled) {
+		svm->vmcb->save.cr3 = hsave->save.cr3;
+		svm->vcpu.arch.cr3 = hsave->save.cr3;
+	} else {
+		(void)kvm_set_cr3(&svm->vcpu, hsave->save.cr3);
+	}
+	kvm_rax_write(&svm->vcpu, hsave->save.rax);
+	kvm_rsp_write(&svm->vcpu, hsave->save.rsp);
+	kvm_rip_write(&svm->vcpu, hsave->save.rip);
+	svm->vmcb->save.dr7 = 0;
+	svm->vmcb->save.cpl = 0;
+	svm->vmcb->control.exit_int_info = 0;
+
+	mark_all_dirty(svm->vmcb);
+
+	kvm_vcpu_unmap(&svm->vcpu, &map, true);
+
+	nested_svm_uninit_mmu_context(&svm->vcpu);
+	kvm_mmu_reset_context(&svm->vcpu);
+	kvm_mmu_load(&svm->vcpu);
+
+	/*
+	 * Drop what we picked up for L2 via svm_complete_interrupts() so it
+	 * doesn't end up in L1.
+	 */
+	svm->vcpu.arch.nmi_injected = false;
+	kvm_clear_exception_queue(&svm->vcpu);
+	kvm_clear_interrupt_queue(&svm->vcpu);
+
+	return 0;
+}
+
+static int nested_svm_exit_handled_msr(struct vcpu_svm *svm)
+{
+	u32 offset, msr, value;
+	int write, mask;
+
+	if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
+		return NESTED_EXIT_HOST;
+
+	msr    = svm->vcpu.arch.regs[VCPU_REGS_RCX];
+	offset = svm_msrpm_offset(msr);
+	write  = svm->vmcb->control.exit_info_1 & 1;
+	mask   = 1 << ((2 * (msr & 0xf)) + write);
+
+	if (offset == MSR_INVALID)
+		return NESTED_EXIT_DONE;
+
+	/* Offset is in 32 bit units but need in 8 bit units */
+	offset *= 4;
+
+	if (kvm_vcpu_read_guest(&svm->vcpu, svm->nested.vmcb_msrpm + offset, &value, 4))
+		return NESTED_EXIT_DONE;
+
+	return (value & mask) ? NESTED_EXIT_DONE : NESTED_EXIT_HOST;
+}
+
+/* DB exceptions for our internal use must not cause vmexit */
+static int nested_svm_intercept_db(struct vcpu_svm *svm)
+{
+	unsigned long dr6;
+
+	/* if we're not singlestepping, it's not ours */
+	if (!svm->nmi_singlestep)
+		return NESTED_EXIT_DONE;
+
+	/* if it's not a singlestep exception, it's not ours */
+	if (kvm_get_dr(&svm->vcpu, 6, &dr6))
+		return NESTED_EXIT_DONE;
+	if (!(dr6 & DR6_BS))
+		return NESTED_EXIT_DONE;
+
+	/* if the guest is singlestepping, it should get the vmexit */
+	if (svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF) {
+		disable_nmi_singlestep(svm);
+		return NESTED_EXIT_DONE;
+	}
+
+	/* it's ours, the nested hypervisor must not see this one */
+	return NESTED_EXIT_HOST;
+}
+
+static int nested_svm_intercept_ioio(struct vcpu_svm *svm)
+{
+	unsigned port, size, iopm_len;
+	u16 val, mask;
+	u8 start_bit;
+	u64 gpa;
+
+	if (!(svm->nested.intercept & (1ULL << INTERCEPT_IOIO_PROT)))
+		return NESTED_EXIT_HOST;
+
+	port = svm->vmcb->control.exit_info_1 >> 16;
+	size = (svm->vmcb->control.exit_info_1 & SVM_IOIO_SIZE_MASK) >>
+		SVM_IOIO_SIZE_SHIFT;
+	gpa  = svm->nested.vmcb_iopm + (port / 8);
+	start_bit = port % 8;
+	iopm_len = (start_bit + size > 8) ? 2 : 1;
+	mask = (0xf >> (4 - size)) << start_bit;
+	val = 0;
+
+	if (kvm_vcpu_read_guest(&svm->vcpu, gpa, &val, iopm_len))
+		return NESTED_EXIT_DONE;
+
+	return (val & mask) ? NESTED_EXIT_DONE : NESTED_EXIT_HOST;
+}
+
+static int nested_svm_intercept(struct vcpu_svm *svm)
+{
+	u32 exit_code = svm->vmcb->control.exit_code;
+	int vmexit = NESTED_EXIT_HOST;
+
+	switch (exit_code) {
+	case SVM_EXIT_MSR:
+		vmexit = nested_svm_exit_handled_msr(svm);
+		break;
+	case SVM_EXIT_IOIO:
+		vmexit = nested_svm_intercept_ioio(svm);
+		break;
+	case SVM_EXIT_READ_CR0 ... SVM_EXIT_WRITE_CR8: {
+		u32 bit = 1U << (exit_code - SVM_EXIT_READ_CR0);
+		if (svm->nested.intercept_cr & bit)
+			vmexit = NESTED_EXIT_DONE;
+		break;
+	}
+	case SVM_EXIT_READ_DR0 ... SVM_EXIT_WRITE_DR7: {
+		u32 bit = 1U << (exit_code - SVM_EXIT_READ_DR0);
+		if (svm->nested.intercept_dr & bit)
+			vmexit = NESTED_EXIT_DONE;
+		break;
+	}
+	case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
+		u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);
+		if (svm->nested.intercept_exceptions & excp_bits) {
+			if (exit_code == SVM_EXIT_EXCP_BASE + DB_VECTOR)
+				vmexit = nested_svm_intercept_db(svm);
+			else
+				vmexit = NESTED_EXIT_DONE;
+		}
+		/* async page fault always cause vmexit */
+		else if ((exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR) &&
+			 svm->vcpu.arch.exception.nested_apf != 0)
+			vmexit = NESTED_EXIT_DONE;
+		break;
+	}
+	case SVM_EXIT_ERR: {
+		vmexit = NESTED_EXIT_DONE;
+		break;
+	}
+	default: {
+		u64 exit_bits = 1ULL << (exit_code - SVM_EXIT_INTR);
+		if (svm->nested.intercept & exit_bits)
+			vmexit = NESTED_EXIT_DONE;
+	}
+	}
+
+	return vmexit;
+}
+
+int nested_svm_exit_handled(struct vcpu_svm *svm)
+{
+	int vmexit;
+
+	vmexit = nested_svm_intercept(svm);
+
+	if (vmexit == NESTED_EXIT_DONE)
+		nested_svm_vmexit(svm);
+
+	return vmexit;
+}
+
+int nested_svm_check_permissions(struct vcpu_svm *svm)
+{
+	if (!(svm->vcpu.arch.efer & EFER_SVME) ||
+	    !is_paging(&svm->vcpu)) {
+		kvm_queue_exception(&svm->vcpu, UD_VECTOR);
+		return 1;
+	}
+
+	if (svm->vmcb->save.cpl) {
+		kvm_inject_gp(&svm->vcpu, 0);
+		return 1;
+	}
+
+	return 0;
+}
+
+int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
+			       bool has_error_code, u32 error_code)
+{
+	int vmexit;
+
+	if (!is_guest_mode(&svm->vcpu))
+		return 0;
+
+	vmexit = nested_svm_intercept(svm);
+	if (vmexit != NESTED_EXIT_DONE)
+		return 0;
+
+	svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + nr;
+	svm->vmcb->control.exit_code_hi = 0;
+	svm->vmcb->control.exit_info_1 = error_code;
+
+	/*
+	 * EXITINFO2 is undefined for all exception intercepts other
+	 * than #PF.
+	 */
+	if (svm->vcpu.arch.exception.nested_apf)
+		svm->vmcb->control.exit_info_2 = svm->vcpu.arch.apf.nested_apf_token;
+	else if (svm->vcpu.arch.exception.has_payload)
+		svm->vmcb->control.exit_info_2 = svm->vcpu.arch.exception.payload;
+	else
+		svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;
+
+	svm->nested.exit_required = true;
+	return vmexit;
+}
+
+static void nested_svm_intr(struct vcpu_svm *svm)
+{
+	svm->vmcb->control.exit_code   = SVM_EXIT_INTR;
+	svm->vmcb->control.exit_info_1 = 0;
+	svm->vmcb->control.exit_info_2 = 0;
+
+	/* nested_svm_vmexit this gets called afterwards from handle_exit */
+	svm->nested.exit_required = true;
+	trace_kvm_nested_intr_vmexit(svm->vmcb->save.rip);
+}
+
+static bool nested_exit_on_intr(struct vcpu_svm *svm)
+{
+	return (svm->nested.intercept & 1ULL);
+}
+
+int svm_check_nested_events(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	bool block_nested_events =
+		kvm_event_needs_reinjection(vcpu) || svm->nested.exit_required;
+
+	if (kvm_cpu_has_interrupt(vcpu) && nested_exit_on_intr(svm)) {
+		if (block_nested_events)
+			return -EBUSY;
+		nested_svm_intr(svm);
+		return 0;
+	}
+
+	return 0;
+}
+
+int nested_svm_exit_special(struct vcpu_svm *svm)
+{
+	u32 exit_code = svm->vmcb->control.exit_code;
+
+	switch (exit_code) {
+	case SVM_EXIT_INTR:
+	case SVM_EXIT_NMI:
+	case SVM_EXIT_EXCP_BASE + MC_VECTOR:
+		return NESTED_EXIT_HOST;
+	case SVM_EXIT_NPF:
+		/* For now we are always handling NPFs when using them */
+		if (npt_enabled)
+			return NESTED_EXIT_HOST;
+		break;
+	case SVM_EXIT_EXCP_BASE + PF_VECTOR:
+		/* When we're shadowing, trap PFs, but not async PF */
+		if (!npt_enabled && svm->vcpu.arch.apf.host_apf_reason == 0)
+			return NESTED_EXIT_HOST;
+		break;
+	default:
+		break;
+	}
+
+	return NESTED_EXIT_CONTINUE;
+}