From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 29 May 2014 11:22:43 +0200 (CEST) Received: from mailapp01.imgtec.com ([195.59.15.196]:41242 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6833400AbaE2JRKpEbLf (ORCPT ); Thu, 29 May 2014 11:17:10 +0200 Received: from KLMAIL01.kl.imgtec.org (unknown [192.168.5.35]) by Websense Email Security Gateway with ESMTPS id 0007094246223; Thu, 29 May 2014 10:17:01 +0100 (IST) Received: from KLMAIL02.kl.imgtec.org (192.168.5.97) by KLMAIL01.kl.imgtec.org (192.168.5.35) with Microsoft SMTP Server (TLS) id 14.3.181.6; Thu, 29 May 2014 10:17:03 +0100 Received: from LEMAIL01.le.imgtec.org (192.168.152.62) by klmail02.kl.imgtec.org (192.168.5.97) with Microsoft SMTP Server (TLS) id 14.3.181.6; Thu, 29 May 2014 10:17:03 +0100 Received: from jhogan-linux.le.imgtec.org (192.168.154.101) by LEMAIL01.le.imgtec.org (192.168.152.62) with Microsoft SMTP Server (TLS) id 14.3.174.1; Thu, 29 May 2014 10:17:03 +0100 From: James Hogan To: Paolo Bonzini CC: Andreas Herrmann , James Hogan , Gleb Natapov , , Ralf Baechle , , Sanjay Lal Subject: [PATCH v2 12/23] MIPS: KVM: Migrate hrtimer to follow VCPU Date: Thu, 29 May 2014 10:16:34 +0100 Message-ID: <1401355005-20370-13-git-send-email-james.hogan@imgtec.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1401355005-20370-1-git-send-email-james.hogan@imgtec.com> References: <1401355005-20370-1-git-send-email-james.hogan@imgtec.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [192.168.154.101] Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 40337 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: james.hogan@imgtec.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips When a VCPU is scheduled in on a different CPU, refresh the hrtimer used for emulating count/compare so that it gets migrated to the same CPU. This should prevent a timer interrupt occurring on a different CPU to where the guest it relates to is running, which would cause the guest timer interrupt not to be delivered until after the next guest exit. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: Gleb Natapov Cc: kvm@vger.kernel.org Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: Sanjay Lal --- v2: - Move kvm_mips_migrate_count() into kvm_tlb.c to fix a link error when KVM is built as a module, since kvm_tlb.c is built statically and cannot reference symbols in kvm_mips_emul.c. --- arch/mips/kvm/kvm_tlb.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/mips/kvm/kvm_tlb.c b/arch/mips/kvm/kvm_tlb.c index 9d371ee0a755..d65999a9f8af 100644 --- a/arch/mips/kvm/kvm_tlb.c +++ b/arch/mips/kvm/kvm_tlb.c @@ -656,6 +656,23 @@ void kvm_local_flush_tlb_all(void) local_irq_restore(flags); } +/** + * kvm_mips_migrate_count() - Migrate timer. + * @vcpu: Virtual CPU. + * + * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it + * if it was running prior to being cancelled. + * + * Must be called when the VCPU is migrated to a different CPU to ensure that + * timer expiry during guest execution interrupts the guest and causes the + * interrupt to be delivered in a timely manner. + */ +static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu) +{ + if (hrtimer_cancel(&vcpu->arch.comparecount_timer)) + hrtimer_restart(&vcpu->arch.comparecount_timer); +} + /* Restore ASID once we are scheduled back after preemption */ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { @@ -691,6 +708,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) if (vcpu->arch.last_sched_cpu != cpu) { kvm_info("[%d->%d]KVM VCPU[%d] switch\n", vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id); + /* + * Migrate the timer interrupt to the current CPU so that it + * always interrupts the guest and synchronously triggers a + * guest timer interrupt. + */ + kvm_mips_migrate_count(vcpu); } if (!newasid) { -- 1.9.3 From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailapp01.imgtec.com ([195.59.15.196]:41242 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6833400AbaE2JRKpEbLf (ORCPT ); Thu, 29 May 2014 11:17:10 +0200 From: James Hogan Subject: [PATCH v2 12/23] MIPS: KVM: Migrate hrtimer to follow VCPU Date: Thu, 29 May 2014 10:16:34 +0100 Message-ID: <1401355005-20370-13-git-send-email-james.hogan@imgtec.com> In-Reply-To: <1401355005-20370-1-git-send-email-james.hogan@imgtec.com> References: <1401355005-20370-1-git-send-email-james.hogan@imgtec.com> MIME-Version: 1.0 Content-Type: text/plain Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: Paolo Bonzini Cc: Andreas Herrmann , James Hogan , Gleb Natapov , kvm@vger.kernel.org, Ralf Baechle , linux-mips@linux-mips.org, Sanjay Lal Message-ID: <20140529091634.2SQ9dK6XoUe5DudAJf0yYX1WnwYLde4KI6O8lJ5FQos@z> When a VCPU is scheduled in on a different CPU, refresh the hrtimer used for emulating count/compare so that it gets migrated to the same CPU. This should prevent a timer interrupt occurring on a different CPU to where the guest it relates to is running, which would cause the guest timer interrupt not to be delivered until after the next guest exit. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: Gleb Natapov Cc: kvm@vger.kernel.org Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: Sanjay Lal --- v2: - Move kvm_mips_migrate_count() into kvm_tlb.c to fix a link error when KVM is built as a module, since kvm_tlb.c is built statically and cannot reference symbols in kvm_mips_emul.c. --- arch/mips/kvm/kvm_tlb.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/mips/kvm/kvm_tlb.c b/arch/mips/kvm/kvm_tlb.c index 9d371ee0a755..d65999a9f8af 100644 --- a/arch/mips/kvm/kvm_tlb.c +++ b/arch/mips/kvm/kvm_tlb.c @@ -656,6 +656,23 @@ void kvm_local_flush_tlb_all(void) local_irq_restore(flags); } +/** + * kvm_mips_migrate_count() - Migrate timer. + * @vcpu: Virtual CPU. + * + * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it + * if it was running prior to being cancelled. + * + * Must be called when the VCPU is migrated to a different CPU to ensure that + * timer expiry during guest execution interrupts the guest and causes the + * interrupt to be delivered in a timely manner. + */ +static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu) +{ + if (hrtimer_cancel(&vcpu->arch.comparecount_timer)) + hrtimer_restart(&vcpu->arch.comparecount_timer); +} + /* Restore ASID once we are scheduled back after preemption */ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { @@ -691,6 +708,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) if (vcpu->arch.last_sched_cpu != cpu) { kvm_info("[%d->%d]KVM VCPU[%d] switch\n", vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id); + /* + * Migrate the timer interrupt to the current CPU so that it + * always interrupts the guest and synchronously triggers a + * guest timer interrupt. + */ + kvm_mips_migrate_count(vcpu); } if (!newasid) { -- 1.9.3