From: Sean Christopherson <seanjc@google.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Babu Moger <babu.moger@amd.com>
Subject: Re: [PATCH 1/2] KVM: SVM: Fix TSC_AUX virtualization setup
Date: Fri, 15 Sep 2023 07:32:47 -0700 [thread overview]
Message-ID: <ZQRrD/CY/pXNlQRX@google.com> (raw)
In-Reply-To: <1e155a46-78f3-51f4-40a0-a94386e8f627@amd.com>
On Fri, Sep 15, 2023, Tom Lendacky wrote:
> On 9/14/23 16:13, Sean Christopherson wrote:
> This toggling possibility raises a question related to the second patch in
> this series that eliminates the use of the user return MSR for TSC_AUX.
> Depending on when the interfaces are called (set CPUID, host-initiated WRMSR
> of TSC_AUX, set CPUID again), I think we could end up in a state where the
> host TSC_AUX may not get restored properly, not 100% sure at the moment,
> though.
Give me a few minutes to respond to patch 2, I think it can be much simpler, more
performant, and avoid any races.
> Let me drop that patch from the series for now and just send the fix(es).
> I'll work through the other scenarios and code paths and send the user
> return MSR optimization as a separate series later.
next prev parent reply other threads:[~2023-09-15 14:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-14 19:50 [PATCH 0/2] SEV-ES TSC_AUX virtualization fix and optimization Tom Lendacky
2023-09-14 19:50 ` [PATCH 1/2] KVM: SVM: Fix TSC_AUX virtualization setup Tom Lendacky
2023-09-14 20:28 ` Sean Christopherson
2023-09-14 20:48 ` Tom Lendacky
2023-09-14 21:13 ` Sean Christopherson
2023-09-15 14:26 ` Tom Lendacky
2023-09-15 14:32 ` Sean Christopherson [this message]
2023-09-15 16:52 ` Tom Lendacky
2023-09-15 17:32 ` Sean Christopherson
2023-09-15 20:54 ` Tom Lendacky
2023-09-14 19:50 ` [PATCH 2/2] KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX Tom Lendacky
2023-09-15 14:43 ` Sean Christopherson
2023-09-15 14:51 ` Sean Christopherson
2023-09-15 15:08 ` Tom Lendacky
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