Undo a nested VMX fix as a step toward reverting the commit it fixed,
15ad9762d69f ("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 a9f2705ec84449e3b8d70c804766f8e97e23080d.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 3 +--
arch/x86/kvm/vmx/vmx.c | 20 +++++++++++---------
arch/x86/kvm/vmx/vmx.h | 5 ++---
3 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index ba34e94049c7..c12f95004a72 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -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;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index efda5e4d6247..beb68cd28aca 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -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;
}
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 7f2c82e7f38f..9c6bfcd84008 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -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);
--
2.35.1.574.g5d30c73bfb-goog
