Drop unnecessary MSR bitmap updates during nested transitions, as L1's
APIC_BASE MSR is not modified by the standard VM-Enter/VM-Exit flows,
and L2's MSR bitmap is managed separately. In the unlikely event that L1
is pathological and loads APIC_BASE via the VM-Exit load list, KVM will
handle updating the bitmap in its normal WRMSR flows.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 6 ------
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/vmx/vmx.h | 1 -
3 files changed, 1 insertion(+), 8 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index a77cfc8bcf11..0d0dd6580cfd 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4305,9 +4305,6 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
kvm_set_dr(vcpu, 7, 0x400);
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
- if (cpu_has_vmx_msr_bitmap())
- vmx_update_msr_bitmap(vcpu);
-
if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr,
vmcs12->vm_exit_msr_load_count))
nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_MSR_FAIL);
@@ -4386,9 +4383,6 @@ static void nested_vmx_restore_host_state(struct kvm_vcpu *vcpu)
kvm_mmu_reset_context(vcpu);
- if (cpu_has_vmx_msr_bitmap())
- vmx_update_msr_bitmap(vcpu);
-
/*
* This nasty bit of open coding is a compromise between blindly
* loading L1's MSRs using the exit load lists (incorrect emulation
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 7e99535a4cbb..f605b43d28e1 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3865,7 +3865,7 @@ static void vmx_update_msr_bitmap_x2apic(struct kvm_vcpu *vcpu, u8 mode)
}
}
-void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu)
+static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
u8 mode = vmx_msr_bitmap_mode(vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index b584e41bed44..1b3dd5ddf235 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -378,7 +378,6 @@ u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);
bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu);
void vmx_update_exception_bitmap(struct kvm_vcpu *vcpu);
-void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
bool vmx_nmi_blocked(struct kvm_vcpu *vcpu);
bool vmx_interrupt_blocked(struct kvm_vcpu *vcpu);
bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu);
--
2.32.0.93.g670b81a890-goog
