From: Vitaly Kuznetsov vkuznets@redhat.com
commit b84155c38076b36d625043a06a2f1c90bde62903 upstream.
In preparation to enabling 'Enlightened MSR Bitmap' feature for Hyper-V guests move MSR bitmap update tracking to a dedicated helper.
Note: vmx_msr_bitmap_l01_changed() is called when MSR bitmap might be updated. KVM doesn't check if the bit we're trying to set is already set (or the bit it's trying to clear is already cleared). Such situations should not be common and a few false positives should not be a problem.
No functional change intended.
Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com Reviewed-by: Maxim Levitsky mlevitsk@redhat.com Reviewed-by: Sean Christopherson seanjc@google.com Message-Id: 20211129094704.326635-3-vkuznets@redhat.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/vmx/vmx.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index eefd6387a99d..ee05c0e1cb2a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3785,6 +3785,17 @@ static void vmx_set_msr_bitmap_write(ulong *msr_bitmap, u32 msr) __set_bit(msr & 0x1fff, msr_bitmap + 0xc00 / f); }
+static void vmx_msr_bitmap_l01_changed(struct vcpu_vmx *vmx) +{ + /* + * When KVM is a nested hypervisor on top of Hyper-V and uses + * 'Enlightened MSR Bitmap' feature L0 needs to know that MSR + * bitmap has changed. + */ + if (static_branch_unlikely(&enable_evmcs)) + evmcs_touch_msr_bitmap(); +} + static __always_inline void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type) { @@ -3794,8 +3805,7 @@ static __always_inline void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu, if (!cpu_has_vmx_msr_bitmap()) return;
- if (static_branch_unlikely(&enable_evmcs)) - evmcs_touch_msr_bitmap(); + vmx_msr_bitmap_l01_changed(vmx);
/* * Mark the desired intercept state in shadow bitmap, this is needed @@ -3840,8 +3850,7 @@ static __always_inline void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, if (!cpu_has_vmx_msr_bitmap()) return;
- if (static_branch_unlikely(&enable_evmcs)) - evmcs_touch_msr_bitmap(); + vmx_msr_bitmap_l01_changed(vmx);
/* * Mark the desired intercept state in shadow bitmap, this is needed