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[54.240.197.236]) by smtp.gmail.com with ESMTPSA id jg36-20020a170907972400b00a526aa9e75asm2378399ejc.77.2024.04.19.08.55.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 19 Apr 2024 08:55:48 -0700 (PDT) From: Paul Durrant X-Google-Original-From: Paul Durrant Message-ID: <15a9176e-9221-44b9-b8df-910c0c16ddc2@xen.org> Date: Fri, 19 Apr 2024 16:55:47 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: paul@xen.org Subject: Re: [PATCH 08/10] KVM: x86: Remove periodic global clock updates To: David Woodhouse , kvm@vger.kernel.org Cc: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Shuah Khan , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Oliver Upton , Marcelo Tosatti , jalliste@amazon.co.uk, sveith@amazon.de References: <20240418193528.41780-1-dwmw2@infradead.org> <20240418193528.41780-9-dwmw2@infradead.org> Content-Language: en-US Organization: Xen Project In-Reply-To: <20240418193528.41780-9-dwmw2@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 18/04/2024 20:34, David Woodhouse wrote: > From: David Woodhouse > > This effectively reverts commit 332967a3eac0 ("x86: kvm: introduce > periodic global clock updates"). The periodic update was introduced to > propagate NTP corrections to the guest KVM clock, when the KVM clock was > based on CLOCK_MONOTONIC. > > However, commit 53fafdbb8b21 ("KVM: x86: switch KVMCLOCK base to > monotonic raw clock") switched to using CLOCK_MONOTONIC_RAW as the basis > for the KVM clock, avoiding the NTP frequency skew altogether. > > So the periodic update serves no purpose. Remove it. > > Signed-off-by: David Woodhouse > --- > arch/x86/kvm/x86.c | 25 ------------------------- > 1 file changed, 25 deletions(-) > Reviewed-by: Paul Durrant