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Dadhania" Cc: Xiaoyao Li , Isaku Yamahata , kvm@vger.kernel.org, pbonzini@redhat.com, Sean Christopherson , chao.gao@intel.com, rick.p.edgecombe@intel.com, yan.y.zhao@intel.com, linux-kernel@vger.kernel.org, isaku.yamahata@gmail.com, Tom Lendacky Subject: Re: [PATCH 0/2] KVM: kvm-coco-queue: Support protected TSC Message-ID: References: <81e6604b-fa84-4b74-b9e6-2a37e8076fd7@intel.com> <714ab7a2-69fa-b08d-deae-6eb91ecba95b@amd.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <714ab7a2-69fa-b08d-deae-6eb91ecba95b@amd.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On Tue, Oct 29, 2024 at 09:34:58AM +0530, Nikunj A. Dadhania wrote: > Hello Marcelo > > On 10/28/2024 10:12 PM, Marcelo Tosatti wrote: > > On Sun, Oct 27, 2024 at 10:06:17PM +0800, Xiaoyao Li wrote: > >> On 10/26/2024 12:24 AM, Marcelo Tosatti wrote: > >>> On Mon, Oct 14, 2024 at 08:17:19PM +0530, Nikunj A. Dadhania wrote: > >>>> Hi Isaku, > >>>> > >>>> On 10/12/2024 1:25 PM, Isaku Yamahata wrote: > >>>>> Choose the first one. With this patch series, SEV-SNP secure TSC can be > >>>>> supported. > >>>> > >>>> I am not sure how will this help SNP Secure TSC, as the GUEST_TSC_OFFSET and > >>>> GUEST_TSC_SCALE are only available to the guest. > >>> > >>> Nikunj, > >>> > >>> FYI: > >>> > >>> SEV-SNP processors (at least the one below) do not seem affected by this problem. > >> > >> Did you apply Secure TSC patches of (guest kernel, KVM and QEMU) manualy? > >> because none of them are merged. > > > > Yes. cyclictest latency, on a system configured with tuned > > realtime-virtual-host/realtime-virtual-guest tuned profiles, > > goes from 30us to 50us. > > Would you be ok if I include your Tested-by in the next version of my Secure TSC patches? > > https://lore.kernel.org/lkml/20241028053431.3439593-1-nikunj@amd.com/ Please don't, haven't tested specifically the patches above. > >> Otherwise, I think SNP guest is still using > >> KVM emulated TSC. > > > > Not in the case the test was made. > > > > Regards, > Nikunj > >