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From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Cathy Avery <cavery@redhat.com>,
	Emanuele Giuseppe Esposito <eesposit@redhat.com>,
	linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [PATCH RFC] KVM: nSVM: Fix L1 state corruption upon return from SMM
Date: Wed, 23 Jun 2021 16:21:48 +0000	[thread overview]
Message-ID: <YNNfnLsc+3qMsdlN@google.com> (raw)
In-Reply-To: <YNNc9lKIzM6wlDNf@google.com>

On Wed, Jun 23, 2021, Sean Christopherson wrote:
> And I believe this hackery is necessary only because nested_svm_vmexit() isn't
> following the architcture in the first place.  I.e. using vmcb01 to restore
> host state is flat out wrong.

Ah, that's not true, using vmcb01 is allowed by "may store some or all host state
in hidden on-chip memory".

From a performance perspective, I do like the SMI/RSM shenanigans.  I'm not
totally opposed to the trickery since I think it will break a guest if and only
if the L1 guest is also violating the APM.  And we're not fudging the spec thaat
much :-)

  reply	other threads:[~2021-06-23 16:21 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23  7:44 [PATCH RFC] KVM: nSVM: Fix L1 state corruption upon return from SMM Vitaly Kuznetsov
2021-06-23  9:39 ` Paolo Bonzini
2021-06-23 11:39   ` Maxim Levitsky
2021-06-23 12:00     ` Paolo Bonzini
2021-06-23 13:01   ` Maxim Levitsky
2021-06-23 13:07     ` Maxim Levitsky
2021-06-23 13:32       ` Vitaly Kuznetsov
2021-06-23 14:41         ` Maxim Levitsky
2021-06-23 16:10           ` Sean Christopherson
2021-06-23 16:21             ` Sean Christopherson [this message]
2021-06-23 20:37               ` Paolo Bonzini
2021-06-24  7:41                 ` Vitaly Kuznetsov
2021-06-24  8:20                 ` Maxim Levitsky
2021-06-24 10:38                   ` Paolo Bonzini
2021-06-24 14:32                     ` Tom Lendacky
2021-06-24 15:36                       ` Maxim Levitsky
2021-06-23 13:21     ` Paolo Bonzini
2021-06-23 14:06       ` Maxim Levitsky

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