From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: nVMX: Dynamically compute max VMCS index for vmcs12
Date: Thu, 22 Jul 2021 15:04:19 +0000 [thread overview]
Message-ID: <YPmI8x2Qu3ZSS5Bc@google.com> (raw)
In-Reply-To: <f5b512e85f2010ddf3ef621b75e3fb389e463a2c.camel@redhat.com>
On Thu, Jul 22, 2021, Maxim Levitsky wrote:
> On Fri, 2021-06-18 at 14:46 -0700, Sean Christopherson wrote:
> > Calculate the max VMCS index for vmcs12 by walking the array to find the
> > actual max index. Hardcoding the index is prone to bitrot, and the
> > calculation is only done on KVM bringup (albeit on every CPU, but there
> > aren't _that_ many null entries in the array).
> >
> > Fixes: 3c0f99366e34 ("KVM: nVMX: Add a TSC multiplier field in VMCS12")
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
>
> Could you give me an example on how this fails in the KVM unit tests?
> I have a bug report here and it might be related so I want to save some
> time triaging it.
FAIL: VMX_VMCS_ENUM.MAX_INDEX expected: 19, actual: 17
FWIW, unless a kernel/hypervisor is sanity checking VMREAD/VMWRITE or doing something
clever with the MAX_INDEX, I wouldn't expect this to cause any real world failures.
prev parent reply other threads:[~2021-07-22 15:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-18 21:46 [PATCH] KVM: nVMX: Dynamically compute max VMCS index for vmcs12 Sean Christopherson
2021-06-21 16:39 ` Paolo Bonzini
2021-06-21 17:08 ` Sean Christopherson
2021-07-06 3:05 ` Hu, Robert
2021-07-06 5:42 ` Paolo Bonzini
2021-07-21 10:02 ` Hu, Robert
2021-07-21 16:18 ` Sean Christopherson
2021-07-22 2:43 ` Robert Hoo
2021-07-22 7:59 ` Maxim Levitsky
2021-07-22 15:04 ` Sean Christopherson [this message]
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