Merge tag 'f2fs-for-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk...

[mirror_ubuntu-jammy-kernel.git] / 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 "cpuid.h"
#include "lapic.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;

        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.ctl.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.ctl.nested_cr3;
}

static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb *hsave = svm->nested.hsave;

        WARN_ON(mmu_is_nested(vcpu));

        vcpu->arch.mmu = &vcpu->arch.guest_mmu;
        kvm_init_shadow_npt_mmu(vcpu, X86_CR0_PG, hsave->save.cr4, hsave->save.efer,
                                svm->nested.ctl.nested_cr3);
        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;
        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, *g;

        vmcb_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.ctl;

        svm->nested.host_intercept_exceptions = h->intercept_exceptions;

        c->intercept_cr = h->intercept_cr;
        c->intercept_dr = h->intercept_dr;
        c->intercept_exceptions = h->intercept_exceptions;
        c->intercept = h->intercept;

        if (g->int_ctl & V_INTR_MASKING_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_control_area *dst,
                                   struct vmcb_control_area *from)
{
        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;
        /* asid not copied, it is handled manually for svm->vmcb.  */
        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.ctl.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.ctl.msrpm_base_pa + (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_check_controls(struct vmcb_control_area *control)
{
        if ((control->intercept & (1ULL << INTERCEPT_VMRUN)) == 0)
                return false;

        if (control->asid == 0)
                return false;

        if ((control->nested_ctl & SVM_NESTED_CTL_NP_ENABLE) &&
            !npt_enabled)
                return false;

        return true;
}

static bool nested_vmcb_checks(struct vcpu_svm *svm, struct vmcb *vmcb)
{
        bool nested_vmcb_lma;
        if ((vmcb->save.efer & EFER_SVME) == 0)
                return false;

        if (((vmcb->save.cr0 & X86_CR0_CD) == 0) &&
            (vmcb->save.cr0 & X86_CR0_NW))
                return false;

        if (!kvm_dr6_valid(vmcb->save.dr6) || !kvm_dr7_valid(vmcb->save.dr7))
                return false;

        nested_vmcb_lma =
                (vmcb->save.efer & EFER_LME) &&
                (vmcb->save.cr0 & X86_CR0_PG);

        if (!nested_vmcb_lma) {
                if (vmcb->save.cr4 & X86_CR4_PAE) {
                        if (vmcb->save.cr3 & MSR_CR3_LEGACY_PAE_RESERVED_MASK)
                                return false;
                } else {
                        if (vmcb->save.cr3 & MSR_CR3_LEGACY_RESERVED_MASK)
                                return false;
                }
        } else {
                if (!(vmcb->save.cr4 & X86_CR4_PAE) ||
                    !(vmcb->save.cr0 & X86_CR0_PE) ||
                    (vmcb->save.cr3 & MSR_CR3_LONG_RESERVED_MASK))
                        return false;
        }
        if (kvm_valid_cr4(&svm->vcpu, vmcb->save.cr4))
                return false;

        return nested_vmcb_check_controls(&vmcb->control);
}

static void load_nested_vmcb_control(struct vcpu_svm *svm,
                                     struct vmcb_control_area *control)
{
        copy_vmcb_control_area(&svm->nested.ctl, control);

        /* Copy it here because nested_svm_check_controls will check it.  */
        svm->nested.ctl.asid           = control->asid;
        svm->nested.ctl.msrpm_base_pa &= ~0x0fffULL;
        svm->nested.ctl.iopm_base_pa  &= ~0x0fffULL;
}

/*
 * Synchronize fields that are written by the processor, so that
 * they can be copied back into the nested_vmcb.
 */
void sync_nested_vmcb_control(struct vcpu_svm *svm)
{
        u32 mask;
        svm->nested.ctl.event_inj      = svm->vmcb->control.event_inj;
        svm->nested.ctl.event_inj_err  = svm->vmcb->control.event_inj_err;

        /* Only a few fields of int_ctl are written by the processor.  */
        mask = V_IRQ_MASK | V_TPR_MASK;
        if (!(svm->nested.ctl.int_ctl & V_INTR_MASKING_MASK) &&
            svm_is_intercept(svm, INTERCEPT_VINTR)) {
                /*
                 * In order to request an interrupt window, L0 is usurping
                 * svm->vmcb->control.int_ctl and possibly setting V_IRQ
                 * even if it was clear in L1's VMCB.  Restoring it would be
                 * wrong.  However, in this case V_IRQ will remain true until
                 * interrupt_window_interception calls svm_clear_vintr and
                 * restores int_ctl.  We can just leave it aside.
                 */
                mask &= ~V_IRQ_MASK;
        }
        svm->nested.ctl.int_ctl        &= ~mask;
        svm->nested.ctl.int_ctl        |= svm->vmcb->control.int_ctl & mask;
}

/*
 * Transfer any event that L0 or L1 wanted to inject into L2 to
 * EXIT_INT_INFO.
 */
static void nested_vmcb_save_pending_event(struct vcpu_svm *svm,
                                           struct vmcb *nested_vmcb)
{
        struct kvm_vcpu *vcpu = &svm->vcpu;
        u32 exit_int_info = 0;
        unsigned int nr;

        if (vcpu->arch.exception.injected) {
                nr = vcpu->arch.exception.nr;
                exit_int_info = nr | SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_EXEPT;

                if (vcpu->arch.exception.has_error_code) {
                        exit_int_info |= SVM_EVTINJ_VALID_ERR;
                        nested_vmcb->control.exit_int_info_err =
                                vcpu->arch.exception.error_code;
                }

        } else if (vcpu->arch.nmi_injected) {
                exit_int_info = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI;

        } else if (vcpu->arch.interrupt.injected) {
                nr = vcpu->arch.interrupt.nr;
                exit_int_info = nr | SVM_EVTINJ_VALID;

                if (vcpu->arch.interrupt.soft)
                        exit_int_info |= SVM_EVTINJ_TYPE_SOFT;
                else
                        exit_int_info |= SVM_EVTINJ_TYPE_INTR;
        }

        nested_vmcb->control.exit_int_info = exit_int_info;
}

static inline bool nested_npt_enabled(struct vcpu_svm *svm)
{
        return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
}

/*
 * Load guest's/host's cr3 on nested vmentry or vmexit. @nested_npt is true
 * if we are emulating VM-Entry into a guest with NPT enabled.
 */
static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
                               bool nested_npt)
{
        if (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63))
                return -EINVAL;

        if (!nested_npt && is_pae_paging(vcpu) &&
            (cr3 != kvm_read_cr3(vcpu) || pdptrs_changed(vcpu))) {
                if (!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
                        return -EINVAL;
        }

        /*
         * TODO: optimize unconditional TLB flush/MMU sync here and in
         * kvm_init_shadow_npt_mmu().
         */
        if (!nested_npt)
                kvm_mmu_new_pgd(vcpu, cr3, false, false);

        vcpu->arch.cr3 = cr3;
        kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);

        kvm_init_mmu(vcpu, false);

        return 0;
}

static void nested_prepare_vmcb_save(struct vcpu_svm *svm, struct vmcb *nested_vmcb)
{
        /* 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);
        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;
}

static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
{
        const u32 mask = V_INTR_MASKING_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK;

        if (nested_npt_enabled(svm))
                nested_svm_init_mmu_context(&svm->vcpu);

        svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset =
                svm->vcpu.arch.l1_tsc_offset + svm->nested.ctl.tsc_offset;

        svm->vmcb->control.int_ctl             =
                (svm->nested.ctl.int_ctl & ~mask) |
                (svm->nested.hsave->control.int_ctl & mask);

        svm->vmcb->control.virt_ext            = svm->nested.ctl.virt_ext;
        svm->vmcb->control.int_vector          = svm->nested.ctl.int_vector;
        svm->vmcb->control.int_state           = svm->nested.ctl.int_state;
        svm->vmcb->control.event_inj           = svm->nested.ctl.event_inj;
        svm->vmcb->control.event_inj_err       = svm->nested.ctl.event_inj_err;

        svm->vmcb->control.pause_filter_count  = svm->nested.ctl.pause_filter_count;
        svm->vmcb->control.pause_filter_thresh = svm->nested.ctl.pause_filter_thresh;

        /* 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);

        vmcb_mark_all_dirty(svm->vmcb);
}

int enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
                          struct vmcb *nested_vmcb)
{
        int ret;

        svm->nested.vmcb = vmcb_gpa;
        load_nested_vmcb_control(svm, &nested_vmcb->control);
        nested_prepare_vmcb_save(svm, nested_vmcb);
        nested_prepare_vmcb_control(svm);

        ret = nested_svm_load_cr3(&svm->vcpu, nested_vmcb->save.cr3,
                                  nested_npt_enabled(svm));
        if (ret)
                return ret;

        svm_set_gif(svm, true);

        return 0;
}

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;

        if (is_smm(&svm->vcpu)) {
                kvm_queue_exception(&svm->vcpu, UD_VECTOR);
                return 1;
        }

        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(svm, 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;
                goto out;
        }

        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->control, &vmcb->control);

        svm->nested.nested_run_pending = 1;

        if (enter_svm_guest_mode(svm, vmcb_gpa, nested_vmcb))
                goto out_exit_err;

        if (nested_svm_vmrun_msrpm(svm))
                goto out;

out_exit_err:
        svm->nested.nested_run_pending = 0;

        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);

out:
        kvm_vcpu_unmap(&svm->vcpu, &map, true);

        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;

        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;
        WARN_ON_ONCE(svm->nested.nested_run_pending);

        /* in case we halted in L2 */
        svm->vcpu.arch.mp_state = KVM_MP_STATE_RUNNABLE;

        /* Give the current vmcb to the guest */
        svm_set_gif(svm, false);

        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    = kvm_rip_read(&svm->vcpu);
        nested_vmcb->save.rsp    = kvm_rsp_read(&svm->vcpu);
        nested_vmcb->save.rax    = kvm_rax_read(&svm->vcpu);
        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_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;

        if (nested_vmcb->control.exit_code != SVM_EXIT_ERR)
                nested_vmcb_save_pending_event(svm, nested_vmcb);

        if (svm->nrips_enabled)
                nested_vmcb->control.next_rip  = vmcb->control.next_rip;

        nested_vmcb->control.int_ctl           = svm->nested.ctl.int_ctl;
        nested_vmcb->control.tlb_ctl           = svm->nested.ctl.tlb_ctl;
        nested_vmcb->control.event_inj         = svm->nested.ctl.event_inj;
        nested_vmcb->control.event_inj_err     = svm->nested.ctl.event_inj_err;

        nested_vmcb->control.pause_filter_count =
                svm->vmcb->control.pause_filter_count;
        nested_vmcb->control.pause_filter_thresh =
                svm->vmcb->control.pause_filter_thresh;

        /* Restore the original control entries */
        copy_vmcb_control_area(&vmcb->control, &hsave->control);

        svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset =
                svm->vcpu.arch.l1_tsc_offset;

        svm->nested.ctl.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);
        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;

        vmcb_mark_all_dirty(svm->vmcb);

        trace_kvm_nested_vmexit_inject(nested_vmcb->control.exit_code,
                                       nested_vmcb->control.exit_info_1,
                                       nested_vmcb->control.exit_info_2,
                                       nested_vmcb->control.exit_int_info,
                                       nested_vmcb->control.exit_int_info_err,
                                       KVM_ISA_SVM);

        kvm_vcpu_unmap(&svm->vcpu, &map, true);

        nested_svm_uninit_mmu_context(&svm->vcpu);

        rc = nested_svm_load_cr3(&svm->vcpu, hsave->save.cr3, false);
        if (rc)
                return 1;

        if (npt_enabled)
                svm->vmcb->save.cr3 = hsave->save.cr3;

        /*
         * 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;
}

/*
 * Forcibly leave nested mode in order to be able to reset the VCPU later on.
 */
void svm_leave_nested(struct vcpu_svm *svm)
{
        if (is_guest_mode(&svm->vcpu)) {
                struct vmcb *hsave = svm->nested.hsave;
                struct vmcb *vmcb = svm->vmcb;

                svm->nested.nested_run_pending = 0;
                leave_guest_mode(&svm->vcpu);
                copy_vmcb_control_area(&vmcb->control, &hsave->control);
                nested_svm_uninit_mmu_context(&svm->vcpu);
        }
}

static int nested_svm_exit_handled_msr(struct vcpu_svm *svm)
{
        u32 offset, msr, value;
        int write, mask;

        if (!(svm->nested.ctl.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.ctl.msrpm_base_pa + offset, &value, 4))
                return NESTED_EXIT_DONE;

        return (value & mask) ? NESTED_EXIT_DONE : 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.ctl.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.ctl.iopm_base_pa + (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.ctl.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.ctl.intercept_dr & bit)
                        vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
                /*
                 * Host-intercepted exceptions have been checked already in
                 * nested_svm_exit_special.  There is nothing to do here,
                 * the vmexit is injected by svm_check_nested_events.
                 */
                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.ctl.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;
}

static bool nested_exit_on_exception(struct vcpu_svm *svm)
{
        unsigned int nr = svm->vcpu.arch.exception.nr;

        return (svm->nested.ctl.intercept_exceptions & (1 << nr));
}

static void nested_svm_inject_exception_vmexit(struct vcpu_svm *svm)
{
        unsigned int nr = svm->vcpu.arch.exception.nr;

        svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + nr;
        svm->vmcb->control.exit_code_hi = 0;

        if (svm->vcpu.arch.exception.has_error_code)
                svm->vmcb->control.exit_info_1 = svm->vcpu.arch.exception.error_code;

        /*
         * EXITINFO2 is undefined for all exception intercepts other
         * than #PF.
         */
        if (nr == PF_VECTOR) {
                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;
        } else if (nr == DB_VECTOR) {
                /* See inject_pending_event.  */
                kvm_deliver_exception_payload(&svm->vcpu);
                if (svm->vcpu.arch.dr7 & DR7_GD) {
                        svm->vcpu.arch.dr7 &= ~DR7_GD;
                        kvm_update_dr7(&svm->vcpu);
                }
        } else
                WARN_ON(svm->vcpu.arch.exception.has_payload);

        nested_svm_vmexit(svm);
}

static void nested_svm_smi(struct vcpu_svm *svm)
{
        svm->vmcb->control.exit_code = SVM_EXIT_SMI;
        svm->vmcb->control.exit_info_1 = 0;
        svm->vmcb->control.exit_info_2 = 0;

        nested_svm_vmexit(svm);
}

static void nested_svm_nmi(struct vcpu_svm *svm)
{
        svm->vmcb->control.exit_code = SVM_EXIT_NMI;
        svm->vmcb->control.exit_info_1 = 0;
        svm->vmcb->control.exit_info_2 = 0;

        nested_svm_vmexit(svm);
}

static void nested_svm_intr(struct vcpu_svm *svm)
{
        trace_kvm_nested_intr_vmexit(svm->vmcb->save.rip);

        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(svm);
}

static inline bool nested_exit_on_init(struct vcpu_svm *svm)
{
        return (svm->nested.ctl.intercept & (1ULL << INTERCEPT_INIT));
}

static void nested_svm_init(struct vcpu_svm *svm)
{
        svm->vmcb->control.exit_code   = SVM_EXIT_INIT;
        svm->vmcb->control.exit_info_1 = 0;
        svm->vmcb->control.exit_info_2 = 0;

        nested_svm_vmexit(svm);
}


static 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.nested_run_pending;
        struct kvm_lapic *apic = vcpu->arch.apic;

        if (lapic_in_kernel(vcpu) &&
            test_bit(KVM_APIC_INIT, &apic->pending_events)) {
                if (block_nested_events)
                        return -EBUSY;
                if (!nested_exit_on_init(svm))
                        return 0;
                nested_svm_init(svm);
                return 0;
        }

        if (vcpu->arch.exception.pending) {
                if (block_nested_events)
                        return -EBUSY;
                if (!nested_exit_on_exception(svm))
                        return 0;
                nested_svm_inject_exception_vmexit(svm);
                return 0;
        }

        if (vcpu->arch.smi_pending && !svm_smi_blocked(vcpu)) {
                if (block_nested_events)
                        return -EBUSY;
                if (!nested_exit_on_smi(svm))
                        return 0;
                nested_svm_smi(svm);
                return 0;
        }

        if (vcpu->arch.nmi_pending && !svm_nmi_blocked(vcpu)) {
                if (block_nested_events)
                        return -EBUSY;
                if (!nested_exit_on_nmi(svm))
                        return 0;
                nested_svm_nmi(svm);
                return 0;
        }

        if (kvm_cpu_has_interrupt(vcpu) && !svm_interrupt_blocked(vcpu)) {
                if (block_nested_events)
                        return -EBUSY;
                if (!nested_exit_on_intr(svm))
                        return 0;
                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_NPF:
                return NESTED_EXIT_HOST;
        case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
                u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);

                if (get_host_vmcb(svm)->control.intercept_exceptions & excp_bits)
                        return NESTED_EXIT_HOST;
                else if (exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR &&
                         svm->vcpu.arch.apf.host_apf_flags)
                        /* Trap async PF even if not shadowing */
                        return NESTED_EXIT_HOST;
                break;
        }
        default:
                break;
        }

        return NESTED_EXIT_CONTINUE;
}

static int svm_get_nested_state(struct kvm_vcpu *vcpu,
                                struct kvm_nested_state __user *user_kvm_nested_state,
                                u32 user_data_size)
{
        struct vcpu_svm *svm;
        struct kvm_nested_state kvm_state = {
                .flags = 0,
                .format = KVM_STATE_NESTED_FORMAT_SVM,
                .size = sizeof(kvm_state),
        };
        struct vmcb __user *user_vmcb = (struct vmcb __user *)
                &user_kvm_nested_state->data.svm[0];

        if (!vcpu)
                return kvm_state.size + KVM_STATE_NESTED_SVM_VMCB_SIZE;

        svm = to_svm(vcpu);

        if (user_data_size < kvm_state.size)
                goto out;

        /* First fill in the header and copy it out.  */
        if (is_guest_mode(vcpu)) {
                kvm_state.hdr.svm.vmcb_pa = svm->nested.vmcb;
                kvm_state.size += KVM_STATE_NESTED_SVM_VMCB_SIZE;
                kvm_state.flags |= KVM_STATE_NESTED_GUEST_MODE;

                if (svm->nested.nested_run_pending)
                        kvm_state.flags |= KVM_STATE_NESTED_RUN_PENDING;
        }

        if (gif_set(svm))
                kvm_state.flags |= KVM_STATE_NESTED_GIF_SET;

        if (copy_to_user(user_kvm_nested_state, &kvm_state, sizeof(kvm_state)))
                return -EFAULT;

        if (!is_guest_mode(vcpu))
                goto out;

        /*
         * Copy over the full size of the VMCB rather than just the size
         * of the structs.
         */
        if (clear_user(user_vmcb, KVM_STATE_NESTED_SVM_VMCB_SIZE))
                return -EFAULT;
        if (copy_to_user(&user_vmcb->control, &svm->nested.ctl,
                         sizeof(user_vmcb->control)))
                return -EFAULT;
        if (copy_to_user(&user_vmcb->save, &svm->nested.hsave->save,
                         sizeof(user_vmcb->save)))
                return -EFAULT;

out:
        return kvm_state.size;
}

static int svm_set_nested_state(struct kvm_vcpu *vcpu,
                                struct kvm_nested_state __user *user_kvm_nested_state,
                                struct kvm_nested_state *kvm_state)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb *hsave = svm->nested.hsave;
        struct vmcb __user *user_vmcb = (struct vmcb __user *)
                &user_kvm_nested_state->data.svm[0];
        struct vmcb_control_area ctl;
        struct vmcb_save_area save;
        u32 cr0;

        if (kvm_state->format != KVM_STATE_NESTED_FORMAT_SVM)
                return -EINVAL;

        if (kvm_state->flags & ~(KVM_STATE_NESTED_GUEST_MODE |
                                 KVM_STATE_NESTED_RUN_PENDING |
                                 KVM_STATE_NESTED_GIF_SET))
                return -EINVAL;

        /*
         * If in guest mode, vcpu->arch.efer actually refers to the L2 guest's
         * EFER.SVME, but EFER.SVME still has to be 1 for VMRUN to succeed.
         */
        if (!(vcpu->arch.efer & EFER_SVME)) {
                /* GIF=1 and no guest mode are required if SVME=0.  */
                if (kvm_state->flags != KVM_STATE_NESTED_GIF_SET)
                        return -EINVAL;
        }

        /* SMM temporarily disables SVM, so we cannot be in guest mode.  */
        if (is_smm(vcpu) && (kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
                return -EINVAL;

        if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE)) {
                svm_leave_nested(svm);
                goto out_set_gif;
        }

        if (!page_address_valid(vcpu, kvm_state->hdr.svm.vmcb_pa))
                return -EINVAL;
        if (kvm_state->size < sizeof(*kvm_state) + KVM_STATE_NESTED_SVM_VMCB_SIZE)
                return -EINVAL;
        if (copy_from_user(&ctl, &user_vmcb->control, sizeof(ctl)))
                return -EFAULT;
        if (copy_from_user(&save, &user_vmcb->save, sizeof(save)))
                return -EFAULT;

        if (!nested_vmcb_check_controls(&ctl))
                return -EINVAL;

        /*
         * Processor state contains L2 state.  Check that it is
         * valid for guest mode (see nested_vmcb_checks).
         */
        cr0 = kvm_read_cr0(vcpu);
        if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW))
                return -EINVAL;

        /*
         * Validate host state saved from before VMRUN (see
         * nested_svm_check_permissions).
         * TODO: validate reserved bits for all saved state.
         */
        if (!(save.cr0 & X86_CR0_PG))
                return -EINVAL;

        /*
         * All checks done, we can enter guest mode.  L1 control fields
         * come from the nested save state.  Guest state is already
         * in the registers, the save area of the nested state instead
         * contains saved L1 state.
         */
        copy_vmcb_control_area(&hsave->control, &svm->vmcb->control);
        hsave->save = save;

        svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa;
        load_nested_vmcb_control(svm, &ctl);
        nested_prepare_vmcb_control(svm);

out_set_gif:
        svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET));
        return 0;
}

struct kvm_x86_nested_ops svm_nested_ops = {
        .check_events = svm_check_nested_events,
        .get_state = svm_get_nested_state,
        .set_state = svm_set_nested_state,
};