linux-kernel - Re: [PATCH 3/3] X86/nVMX: Update the MSR_BITMAP field with the L02 MSR BITMAP

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Date:   Fri, 9 Feb 2018 15:26:51 -0800
From:   Jim Mattson <jmattson@...gle.com>
To:     KarimAllah Ahmed <karahmed@...zon.de>
Cc:     kvm list <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: Re: [PATCH 3/3] X86/nVMX: Update the MSR_BITMAP field with the L02
 MSR BITMAP

On Thu, Feb 8, 2018 at 2:53 PM, KarimAllah Ahmed <karahmed@...zon.de> wrote:
> ... otherwise we will just be running with the L1 MSR BITMAP!
>
> It does not seem that we ever update the MSR_BITMAP when the nested guest
> is running. The only place where we update the MSR_BITMAP field in VMCS is
> for the L1 guest!
>
> Signed-off-by: KarimAllah Ahmed <karahmed@...zon.de>
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Cc: Radim Krčmář <rkrcmar@...hat.com>
> Cc: kvm@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
>  arch/x86/kvm/vmx.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 91e3539..f40be10 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -10589,6 +10589,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
>         vmcs_writel(GUEST_GDTR_BASE, vmcs12->guest_gdtr_base);
>         vmcs_writel(GUEST_IDTR_BASE, vmcs12->guest_idtr_base);
>
> +       if (cpu_has_vmx_msr_bitmap())
> +               vmcs_write64(MSR_BITMAP, __pa(vmx->nested.vmcs02.msr_bitmap));
> +

This is already in David's "[PATCH 5/9] KVM: VMX: make MSR bitmaps
per-VCPU," isn't it?

>         if (from_vmentry &&
>             (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) {
>                 kvm_set_dr(vcpu, 7, vmcs12->guest_dr7);
> --
> 2.7.4
>