We need to change the default all-1s bitmap if the MSRs are _not_ intercepted. However, the code was disabling the intercept when it was _enabled_ in the VMCS01. This is not causing bigger trouble, because vmx_vcpu_run checks the VMCS02's MSR bitmap and would do the right thing even if fed garbage... but it's obviously a bug and it can cause extra MSR reads and writes when running nested guests.
Fixes: d28b387fb74da95d69d2615732f50cceb38e9a4d Fixes: 15d45071523d89b3fb7372e2135fbd72f6af9506 Cc: [email protected] Cc: Radim Krčmář <[email protected]> Cc: KarimAllah Ahmed <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Jim Mattson <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: [email protected] Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/vmx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 5caeb8dc5bda..af89d377681d 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -10235,7 +10235,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, return false; if (!nested_cpu_has_virt_x2apic_mode(vmcs12) && - !pred_cmd && !spec_ctrl) + pred_cmd && spec_ctrl) return false; page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->msr_bitmap); @@ -10278,13 +10278,13 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, MSR_TYPE_W); } - if (spec_ctrl) + if (!spec_ctrl) nested_vmx_disable_intercept_for_msr( msr_bitmap_l1, msr_bitmap_l0, MSR_IA32_SPEC_CTRL, MSR_TYPE_R | MSR_TYPE_W); - if (pred_cmd) + if (!pred_cmd) nested_vmx_disable_intercept_for_msr( msr_bitmap_l1, msr_bitmap_l0, MSR_IA32_PRED_CMD, -- 1.8.3.1
