From: Adrian Hunter <adrian.hunter@intel.com>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"kas@kernel.org" <kas@kernel.org>,
"seanjc@google.com" <seanjc@google.com>
Cc: "Li, Xiaoyao" <xiaoyao.li@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Zhao, Yan Y" <yan.y.zhao@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"hou, wenlong" <houwenlong.hwl@antgroup.com>
Subject: Re: [PATCH v4 1/4] KVM: TDX: Synchronize user-return MSRs immediately after VP.ENTER
Date: Tue, 21 Oct 2025 16:37:48 +0300 [thread overview]
Message-ID: <d1628f0e-bbe9-48b0-8881-ad451d4ce9c5@intel.com> (raw)
In-Reply-To: <e16f198e6af0b03fb0f9cfcc5fd4e7a9047aeee1.camel@intel.com>
On 21/10/2025 01:55, Edgecombe, Rick P wrote:
>> + * Several of KVM's user-return MSRs are clobbered by the TDX-Module if
>> + * VP.ENTER succeeds, i.e. on TD-Exit. Mark those MSRs as needing an
>> + * update to synchronize the "current" value in KVM's cache with the
>> + * value in hardware (loaded by the TDX-Module).
>> + */
>
> I think we should be synchronizing only after a successful VP.ENTER with a real
> TD exit, but today instead we synchronize after any attempt to VP.ENTER.
If the MSR's do not get clobbered, does it matter whether or not they get
restored.
next prev parent reply other threads:[~2025-10-21 13:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 22:28 [PATCH v4 0/4] KVM: x86: User-return MSR cleanups Sean Christopherson
2025-10-16 22:28 ` [PATCH v4 1/4] KVM: TDX: Synchronize user-return MSRs immediately after VP.ENTER Sean Christopherson
2025-10-20 22:55 ` Edgecombe, Rick P
2025-10-21 13:37 ` Adrian Hunter [this message]
2025-10-21 15:06 ` Sean Christopherson
2025-10-21 16:36 ` Adrian Hunter
2025-10-21 16:46 ` Sean Christopherson
2025-10-21 18:54 ` Edgecombe, Rick P
2025-10-21 19:33 ` Sean Christopherson
2025-10-21 20:49 ` Edgecombe, Rick P
2025-10-23 5:59 ` Xiaoyao Li
2025-10-16 22:28 ` [PATCH v4 2/4] KVM: x86: Leave user-return notifier registered on reboot/shutdown Sean Christopherson
2025-10-17 5:32 ` Chao Gao
2025-10-17 15:27 ` Sean Christopherson
2025-10-16 22:28 ` [PATCH v4 3/4] KVM: x86: Don't disable IRQs when unregistering user-return notifier Sean Christopherson
2025-10-16 22:28 ` [PATCH v4 4/4] KVM: x86: Drop "cache" from user return MSR setter that skips WRMSR Sean Christopherson
2025-10-17 2:52 ` Chao Gao
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