Re: [PATCH 2/3] KVM: nVMX: fix wrong condition for SPEC_CTRL and PRED_CMD MSRs

From: Jim Mattson
Date: Wed Feb 21 2018 - 19:07:42 EST


On Wed, Feb 21, 2018 at 1:41 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> 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: x86@xxxxxxxxxx
> Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
> Cc: KarimAllah Ahmed <karahmed@xxxxxxxxx>
> Cc: David Woodhouse <dwmw@xxxxxxxxxxxx>
> Cc: Jim Mattson <jmattson@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>

Wasn't this already fixed by 206587a9fb76 ("X86/nVMX: Properly set
spec_ctrl and pred_cmd before merging MSRs")?