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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id cf16sm420363edb.51.2021.09.24.09.42.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Sep 2021 09:42:31 -0700 (PDT) Message-ID: Date: Fri, 24 Sep 2021 18:42:26 +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 5/7] kvm: x86: protect masterclock with a seqcount Content-Language: en-US To: Oliver Upton , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Sean Christopherson , Marc Zyngier , Peter Shier , Jim Mattson , David Matlack , Ricardo Koller , Jing Zhang , Raghavendra Rao Anata , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Andrew Jones , Will Deacon , Catalin Marinas References: <20210916181538.968978-1-oupton@google.com> <20210916181538.968978-6-oupton@google.com> From: Paolo Bonzini In-Reply-To: <20210916181538.968978-6-oupton@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 16/09/21 20:15, Oliver Upton wrote: > From: Paolo Bonzini > > Protect the reference point for kvmclock with a seqcount, so that > kvmclock updates for all vCPUs can proceed in parallel. Xen runstate > updates will also run in parallel and not bounce the kvmclock cacheline. > > nr_vcpus_matched_tsc is updated outside pvclock_update_vm_gtod_copy > though, so a spinlock must be kept for that one. > > Signed-off-by: Paolo Bonzini > [Oliver - drop unused locals, don't double acquire tsc_write_lock] > Signed-off-by: Oliver Upton > --- This needs a small adjustment: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 07d00e711043..b0c21d42f453 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11289,6 +11289,7 @@ void kvm_arch_free_vm(struct kvm *kvm) int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) { int ret; + unsigned long flags; if (type) return -EINVAL; @@ -11314,7 +11315,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) mutex_init(&kvm->arch.apic_map_lock); seqcount_raw_spinlock_init(&kvm->arch.pvclock_sc, &kvm->arch.tsc_write_lock); kvm->arch.kvmclock_offset = -get_kvmclock_base_ns(); + + raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); pvclock_update_vm_gtod_copy(kvm); + raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); kvm->arch.guest_can_read_msr_platform_info = true; From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6B35C433F5 for ; Fri, 24 Sep 2021 16:42:41 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 1537060EE7 for ; Fri, 24 Sep 2021 16:42:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1537060EE7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 6C3DE4B0C2; Fri, 24 Sep 2021 12:42:40 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); 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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id cf16sm420363edb.51.2021.09.24.09.42.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Sep 2021 09:42:31 -0700 (PDT) Message-ID: Date: Fri, 24 Sep 2021 18:42:26 +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 5/7] kvm: x86: protect masterclock with a seqcount To: Oliver Upton , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu References: <20210916181538.968978-1-oupton@google.com> <20210916181538.968978-6-oupton@google.com> From: Paolo Bonzini In-Reply-To: <20210916181538.968978-6-oupton@google.com> 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 , Will Deacon , Peter Shier , Marc Zyngier , David Matlack , 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 16/09/21 20:15, Oliver Upton wrote: > From: Paolo Bonzini > > Protect the reference point for kvmclock with a seqcount, so that > kvmclock updates for all vCPUs can proceed in parallel. Xen runstate > updates will also run in parallel and not bounce the kvmclock cacheline. > > nr_vcpus_matched_tsc is updated outside pvclock_update_vm_gtod_copy > though, so a spinlock must be kept for that one. > > Signed-off-by: Paolo Bonzini > [Oliver - drop unused locals, don't double acquire tsc_write_lock] > Signed-off-by: Oliver Upton > --- This needs a small adjustment: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 07d00e711043..b0c21d42f453 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11289,6 +11289,7 @@ void kvm_arch_free_vm(struct kvm *kvm) int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) { int ret; + unsigned long flags; if (type) return -EINVAL; @@ -11314,7 +11315,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) mutex_init(&kvm->arch.apic_map_lock); seqcount_raw_spinlock_init(&kvm->arch.pvclock_sc, &kvm->arch.tsc_write_lock); kvm->arch.kvmclock_offset = -get_kvmclock_base_ns(); + + raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); pvclock_update_vm_gtod_copy(kvm); + raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); kvm->arch.guest_can_read_msr_platform_info = true; _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 044D9C433F5 for ; Fri, 24 Sep 2021 16:44:59 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C39A36124B for ; Fri, 24 Sep 2021 16:44:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C39A36124B Authentication-Results: mail.kernel.org; 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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id cf16sm420363edb.51.2021.09.24.09.42.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Sep 2021 09:42:31 -0700 (PDT) Message-ID: Date: Fri, 24 Sep 2021 18:42:26 +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 5/7] kvm: x86: protect masterclock with a seqcount To: Oliver Upton , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Sean Christopherson , Marc Zyngier , Peter Shier , Jim Mattson , David Matlack , Ricardo Koller , Jing Zhang , Raghavendra Rao Anata , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Andrew Jones , Will Deacon , Catalin Marinas References: <20210916181538.968978-1-oupton@google.com> <20210916181538.968978-6-oupton@google.com> From: Paolo Bonzini In-Reply-To: <20210916181538.968978-6-oupton@google.com> 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210924_094237_250078_433D3B61 X-CRM114-Status: GOOD ( 12.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 16/09/21 20:15, Oliver Upton wrote: > From: Paolo Bonzini > > Protect the reference point for kvmclock with a seqcount, so that > kvmclock updates for all vCPUs can proceed in parallel. Xen runstate > updates will also run in parallel and not bounce the kvmclock cacheline. > > nr_vcpus_matched_tsc is updated outside pvclock_update_vm_gtod_copy > though, so a spinlock must be kept for that one. > > Signed-off-by: Paolo Bonzini > [Oliver - drop unused locals, don't double acquire tsc_write_lock] > Signed-off-by: Oliver Upton > --- This needs a small adjustment: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 07d00e711043..b0c21d42f453 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11289,6 +11289,7 @@ void kvm_arch_free_vm(struct kvm *kvm) int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) { int ret; + unsigned long flags; if (type) return -EINVAL; @@ -11314,7 +11315,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) mutex_init(&kvm->arch.apic_map_lock); seqcount_raw_spinlock_init(&kvm->arch.pvclock_sc, &kvm->arch.tsc_write_lock); kvm->arch.kvmclock_offset = -get_kvmclock_base_ns(); + + raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); pvclock_update_vm_gtod_copy(kvm); + raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); kvm->arch.guest_can_read_msr_platform_info = true; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel