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From: Sean Christopherson <seanjc@google.com>
To: Babu Moger <babu.moger@amd.com>
Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
	bp@alien8.de, fenghua.yu@intel.com, tony.luck@intel.com,
	wanpengli@tencent.com, kvm@vger.kernel.org,
	thomas.lendacky@amd.com, peterz@infradead.org, joro@8bytes.org,
	x86@kernel.org, kyung.min.park@intel.com,
	linux-kernel@vger.kernel.org, krish.sadhukhan@oracle.com,
	hpa@zytor.com, mgross@linux.intel.com, vkuznets@redhat.com,
	kim.phillips@amd.com, wei.huang2@amd.com, jmattson@google.com
Subject: Re: [PATCH v3 2/2] KVM: SVM: Add support for Virtual SPEC_CTRL
Date: Tue, 26 Jan 2021 16:13:48 -0800	[thread overview]
Message-ID: <YBCwPHOXgVqnnMQ6@google.com> (raw)
In-Reply-To: <ae97b4c2-6f19-f539-a7ab-f91385449e8f@amd.com>

On Wed, Jan 20, 2021, Babu Moger wrote:
> 
> On 1/19/21 5:45 PM, Sean Christopherson wrote:

> > Potentially harebrained alternative...
> > 
> > From an architectural SVM perspective, what are the rules for VMCB fields that
> > don't exist (on the current hardware)?  E.g. are they reserved MBZ?  If not,
> > does the SVM architecture guarantee that reserved fields will not be modified?
> > I couldn't (quickly) find anything in the APM that explicitly states what
> > happens with defined-but-not-existent fields.
> 
> I checked with our hardware design team about this. They dont want
> software to make any assumptions about these fields.

Drat, I should have begged for forgiveness instead of asking for permission :-D

      reply	other threads:[~2021-01-27  3:51 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-15 17:21 [PATCH v3 0/2] x86: Add the feature Virtual SPEC_CTRL Babu Moger
2021-01-15 17:21 ` [PATCH v3 1/2] x86/cpufeatures: Add the Virtual SPEC_CTRL feature Babu Moger
2021-01-15 17:21 ` [PATCH v3 2/2] KVM: SVM: Add support for Virtual SPEC_CTRL Babu Moger
2021-01-19 18:31   ` Sean Christopherson
2021-01-19 22:29     ` Babu Moger
2021-01-19 23:45       ` Sean Christopherson
2021-01-20 22:09         ` Babu Moger
2021-01-27  0:13           ` Sean Christopherson [this message]

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