linux-kernel - Re: [PATCH 04/12] KVM: selftests: Extend vmx_nested_tsc_scaling

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Message-ID: <qnel5p4xlukvyqmxdm5xhe3zj35dhsbjxj3dxohkrc2chpteus@hmfanp6agg64>
Date: Thu, 9 Oct 2025 23:19:12 +0000
From: Yosry Ahmed <yosry.ahmed@...ux.dev>
To: Jim Mattson <jmattson@...gle.com>
Cc: Sean Christopherson <seanjc@...gle.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/12] KVM: selftests: Extend vmx_nested_tsc_scaling_test
 to cover SVM

On Thu, Oct 09, 2025 at 03:51:13PM -0700, Jim Mattson wrote:
> On Wed, Oct 1, 2025 at 8:03 AM Yosry Ahmed <yosry.ahmed@...ux.dev> wrote:
> >
> > From: Yosry Ahmed <yosryahmed@...gle.com>
> >
> > Add SVM L1 code to run the nested guest, and allow the test to run with
> > SVM as well as VMX.
> >
> > Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
> > ---
> > ...
> > +       /* enable TSC scaling for L2 */
> > +       wrmsr(MSR_AMD64_TSC_RATIO, (L2_SCALE_FACTOR << 32) | 1);
> 
> Why set bit 0 here?

Brainfart. Will fix in the next version, thanks.