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KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()

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The host CR3 in the vcpu thread can only be changed when scheduling.
Moving the code in vmx_prepare_switch_to_guest() makes the code
simpler.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211118110814.2568-5-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Lai Jiangshan 2021-11-18 19:08:03 +08:00 • committed by Paolo Bonzini
parent 3ab4ac877c
commit 15ad9762d6
2 changed files with 11 additions and 14 deletions
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8
arch/x86/kvm/vmx/nested.c
View file

@ -3033,7 +3033,7 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
{ {
struct vcpu_vmx *vmx = to_vmx(vcpu); struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long cr3, cr4; unsigned long cr4;
bool vm_fail; bool vm_fail;
if (!nested_early_check) if (!nested_early_check)
@ -3056,12 +3056,6 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
*/ */
vmcs_writel(GUEST_RFLAGS, 0); vmcs_writel(GUEST_RFLAGS, 0);
cr3 = __get_current_cr3_fast();
if (unlikely(cr3 != vmx->loaded_vmcs->host_state.cr3)) {
vmcs_writel(HOST_CR3, cr3);
vmx->loaded_vmcs->host_state.cr3 = cr3;
}
cr4 = cr4_read_shadow(); cr4 = cr4_read_shadow();
if (unlikely(cr4 != vmx->loaded_vmcs->host_state.cr4)) { if (unlikely(cr4 != vmx->loaded_vmcs->host_state.cr4)) {
vmcs_writel(HOST_CR4, cr4); vmcs_writel(HOST_CR4, cr4);

17
arch/x86/kvm/vmx/vmx.c
View file

@ -1103,6 +1103,7 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
int cpu = raw_smp_processor_id(); int cpu = raw_smp_processor_id();
#endif #endif
unsigned long cr3;
unsigned long fs_base, gs_base; unsigned long fs_base, gs_base;
u16 fs_sel, gs_sel; u16 fs_sel, gs_sel;
int i; int i;
@ -1167,6 +1168,14 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
#endif #endif
vmx_set_host_fs_gs(host_state, fs_sel, gs_sel, fs_base, gs_base); vmx_set_host_fs_gs(host_state, fs_sel, gs_sel, fs_base, gs_base);
/* Host CR3 including its PCID is stable when guest state is loaded. */
cr3 = __get_current_cr3_fast();
if (unlikely(cr3 != host_state->cr3)) {
vmcs_writel(HOST_CR3, cr3);
host_state->cr3 = cr3;
}
vmx->guest_state_loaded = true; vmx->guest_state_loaded = true;
} }
@ -6612,7 +6621,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
{ {
struct vcpu_vmx *vmx = to_vmx(vcpu); struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long cr3, cr4; unsigned long cr4;
/* Record the guest's net vcpu time for enforced NMI injections. */ /* Record the guest's net vcpu time for enforced NMI injections. */
if (unlikely(!enable_vnmi && if (unlikely(!enable_vnmi &&
@ -6657,12 +6666,6 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
vmcs_writel(GUEST_RIP, vcpu->arch.regs[VCPU_REGS_RIP]); vmcs_writel(GUEST_RIP, vcpu->arch.regs[VCPU_REGS_RIP]);
vcpu->arch.regs_dirty = 0; vcpu->arch.regs_dirty = 0;
cr3 = __get_current_cr3_fast();
if (unlikely(cr3 != vmx->loaded_vmcs->host_state.cr3)) {
vmcs_writel(HOST_CR3, cr3);
vmx->loaded_vmcs->host_state.cr3 = cr3;
}
cr4 = cr4_read_shadow(); cr4 = cr4_read_shadow();
if (unlikely(cr4 != vmx->loaded_vmcs->host_state.cr4)) { if (unlikely(cr4 != vmx->loaded_vmcs->host_state.cr4)) {
vmcs_writel(HOST_CR4, cr4); vmcs_writel(HOST_CR4, cr4);