arch/x86/kvm/svm/nested.c

// 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 <asm/debugreg.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->vcpu.arch.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    = svm->vcpu.arch.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 = svm->vmcb->save.dr6;

	/* Always catch it and pass it to userspace if debugging.  */
	if (svm->vcpu.guest_debug &
	    (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
		return NESTED_EXIT_HOST;

	/* if we're not singlestepping, it's not ours */
	if (!svm->nmi_singlestep)
		goto reflected_db;

	/* if it's not a singlestep exception, it's not ours */
	if (!(dr6 & DR6_BS))
		goto reflected_db;

	/* if the guest is singlestepping, it should get the vmexit */
	if (svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF) {
		disable_nmi_singlestep(svm);
		goto reflected_db;
	}

	/* it's ours, the nested hypervisor must not see this one */
	return NESTED_EXIT_HOST;

reflected_db:
	/*
	 * Synchronize guest DR6 here just like in kvm_deliver_exception_payload;
	 * it will be moved into the nested VMCB by nested_svm_vmexit.  Once
	 * exceptions will be moved to svm_check_nested_events, all this stuff
	 * will just go away and we could just return NESTED_EXIT_HOST
	 * unconditionally.  db_interception will queue the exception, which
	 * will be processed by svm_check_nested_events if a nested vmexit is
	 * required, and we will just use kvm_deliver_exception_payload to copy
	 * the payload to DR6 before vmexit.
	 */
	WARN_ON(svm->vcpu.arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT);
	svm->vcpu.arch.dr6 &= ~(DR_TRAP_BITS | DR6_RTM);
	svm->vcpu.arch.dr6 |= dr6 & ~DR6_FIXED_1;
	return NESTED_EXIT_DONE;
}

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 if (exit_code == SVM_EXIT_EXCP_BASE + BP_VECTOR &&
				 svm->vcpu.guest_debug & KVM_GUESTDBG_USE_SW_BP)
				vmexit = NESTED_EXIT_HOST;
			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;
}