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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id l16sm1352795eds.46.2021.09.29.04.20.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Sep 2021 04:20:32 -0700 (PDT) Message-ID: Date: Wed, 29 Sep 2021 13:20:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [PATCH v8 4/7] KVM: x86: Report host tsc and realtime values in KVM_GET_CLOCK To: Marcelo Tosatti , Oliver Upton References: <20210916181538.968978-1-oupton@google.com> <20210916181538.968978-5-oupton@google.com> <20210928185343.GA97247@fuller.cnet> From: Paolo Bonzini In-Reply-To: <20210928185343.GA97247@fuller.cnet> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Cc: Catalin Marinas , kvm@vger.kernel.org, Will Deacon , Peter Shier , Marc Zyngier , David Matlack , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Jim Mattson X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On 28/09/21 20:53, Marcelo Tosatti wrote: >> +KVM_CLOCK_HOST_TSC. If set, the `host_tsc` field in the kvm_clock_data >> +structure is populated with the value of the host's timestamp counter (TSC) >> +at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field >> +does not contain a value. > If the host TSCs are not stable, then KVM_CLOCK_HOST_TSC bit (and > host_tsc field) are ambiguous. Shouldnt exposing them be conditional on > stable TSC for the host ? > Yes, good point. Paolo _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm