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Revert "KVM: VMX: Save HOST_CR3 in vmx_set_host_fs_gs()"

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Undo a nested VMX fix as a step toward reverting the commit it fixed,
15ad9762d6 ("KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()"),
as the underlying premise that "host CR3 in the vcpu thread can only be
changed when scheduling" is wrong.

This reverts commit a9f2705ec8.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220224191917.3508476-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2022-02-24 19:19:16 +00:00
committed by Paolo Bonzini
parent e910a53fb4
commit bca06b85fc
3 changed files with 14 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/kvm/vmx/nested.c
View File

@@ -246,8 +246,7 @@ static void vmx_sync_vmcs_host_state(struct vcpu_vmx *vmx,
src = &prev->host_state;
dest = &vmx->loaded_vmcs->host_state;
vmx_set_vmcs_host_state(dest, src->cr3, src->fs_sel, src->gs_sel,
src->fs_base, src->gs_base);
vmx_set_host_fs_gs(dest, src->fs_sel, src->gs_sel, src->fs_base, src->gs_base);
dest->ldt_sel = src->ldt_sel;
#ifdef CONFIG_X86_64
dest->ds_sel = src->ds_sel;

20
arch/x86/kvm/vmx/vmx.c
View File

@@ -1080,14 +1080,9 @@ static void pt_guest_exit(struct vcpu_vmx *vmx)
wrmsrl(MSR_IA32_RTIT_CTL, vmx->pt_desc.host.ctl);
}
void vmx_set_vmcs_host_state(struct vmcs_host_state *host, unsigned long cr3,
u16 fs_sel, u16 gs_sel,
unsigned long fs_base, unsigned long gs_base)
void vmx_set_host_fs_gs(struct vmcs_host_state *host, u16 fs_sel, u16 gs_sel,
unsigned long fs_base, unsigned long gs_base)
{
if (unlikely(cr3 != host->cr3)) {
vmcs_writel(HOST_CR3, cr3);
host->cr3 = cr3;
}
if (unlikely(fs_sel != host->fs_sel)) {
if (!(fs_sel & 7))
vmcs_write16(HOST_FS_SELECTOR, fs_sel);
@@ -1119,6 +1114,7 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
#ifdef CONFIG_X86_64
int cpu = raw_smp_processor_id();
#endif
unsigned long cr3;
unsigned long fs_base, gs_base;
u16 fs_sel, gs_sel;
int i;
@@ -1182,8 +1178,14 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
gs_base = segment_base(gs_sel);
#endif
vmx_set_vmcs_host_state(host_state, __get_current_cr3_fast(),
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;
}

5
arch/x86/kvm/vmx/vmx.h
View File

@@ -374,9 +374,8 @@ int allocate_vpid(void);
void free_vpid(int vpid);
void vmx_set_constant_host_state(struct vcpu_vmx *vmx);
void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu);
void vmx_set_vmcs_host_state(struct vmcs_host_state *host, unsigned long cr3,
u16 fs_sel, u16 gs_sel,
unsigned long fs_base, unsigned long gs_base);
void vmx_set_host_fs_gs(struct vmcs_host_state *host, u16 fs_sel, u16 gs_sel,
unsigned long fs_base, unsigned long gs_base);
int vmx_get_cpl(struct kvm_vcpu *vcpu);
bool vmx_emulation_required(struct kvm_vcpu *vcpu);
unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu);