From: Christoffer Dall <christoffer.dall@linaro.org> To: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: Marc Zyngier <marc.zyngier@arm.com>, Christoffer Dall <cdall@linaro.org>, Shih-Wei Li <shihwei@cs.columbia.edu>, kvm@vger.kernel.org Subject: [PATCH v4 10/20] KVM: arm/arm64: Use separate timer for phys timer emulation Date: Fri, 20 Oct 2017 13:49:29 +0200 [thread overview] Message-ID: <20171020114939.12554-11-christoffer.dall@linaro.org> (raw) In-Reply-To: <20171020114939.12554-1-christoffer.dall@linaro.org> From: Christoffer Dall <cdall@linaro.org> We were using the same hrtimer for emulating the physical timer and for making sure a blocking VCPU thread would be eventually woken up. That worked fine in the previous arch timer design, but as we are about to actually use the soft timer expire function for the physical timer emulation, change the logic to use a dedicated hrtimer. This has the added benefit of not having to cancel any work in the sync path, which in turn allows us to run the flush and sync with IRQs disabled. Note that the hrtimer used to program the host kernel's timer to generate an exit from the guest when the emulated physical timer fires never has to inject any work, and to share the soft_timer_cancel() function with the bg_timer, we change the function to only cancel any pending work if the pointer to the work struct is not null. Signed-off-by: Christoffer Dall <cdall@linaro.org> --- Notes: Changes since v3: - Check if the work struct pointer is null in soft_timer_cancel() - Moved after we run flush/sync with disabled IRQs to ensure the hrtimer handler doesn't fire. include/kvm/arm_arch_timer.h | 3 +++ virt/kvm/arm/arch_timer.c | 21 ++++++++++++++++----- 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 0eed5bc9fd5e..184c3ef2df93 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -48,6 +48,9 @@ struct arch_timer_cpu { /* Work queued with the above timer expires */ struct work_struct expired; + /* Physical timer emulation */ + struct hrtimer phys_timer; + /* Is the timer enabled */ bool enabled; }; diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 8ec392850e69..4ad853737c34 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -65,7 +65,8 @@ static void soft_timer_start(struct hrtimer *hrt, u64 ns) static void soft_timer_cancel(struct hrtimer *hrt, struct work_struct *work) { hrtimer_cancel(hrt); - cancel_work_sync(work); + if (work) + cancel_work_sync(work); } static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) @@ -172,6 +173,12 @@ static enum hrtimer_restart kvm_bg_timer_expire(struct hrtimer *hrt) return HRTIMER_NORESTART; } +static enum hrtimer_restart kvm_phys_timer_expire(struct hrtimer *hrt) +{ + WARN(1, "Timer only used to ensure guest exit - unexpected event."); + return HRTIMER_NORESTART; +} + bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx) { u64 cval, now; @@ -249,7 +256,7 @@ static void kvm_timer_update_state(struct kvm_vcpu *vcpu) } /* Schedule the background timer for the emulated timer. */ -static void kvm_timer_emulate(struct kvm_vcpu *vcpu, +static void phys_timer_emulate(struct kvm_vcpu *vcpu, struct arch_timer_context *timer_ctx) { struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; @@ -261,7 +268,7 @@ static void kvm_timer_emulate(struct kvm_vcpu *vcpu, return; /* The timer has not yet expired, schedule a background timer */ - soft_timer_start(&timer->bg_timer, kvm_timer_compute_delta(timer_ctx)); + soft_timer_start(&timer->phys_timer, kvm_timer_compute_delta(timer_ctx)); } /* @@ -414,7 +421,7 @@ void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) kvm_timer_update_state(vcpu); /* Set the background timer for the physical timer emulation. */ - kvm_timer_emulate(vcpu, vcpu_ptimer(vcpu)); + phys_timer_emulate(vcpu, vcpu_ptimer(vcpu)); if (unlikely(!irqchip_in_kernel(vcpu->kvm))) kvm_timer_flush_hwstate_user(vcpu); @@ -437,7 +444,7 @@ void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) * This is to cancel the background timer for the physical timer * emulation if it is set. */ - soft_timer_cancel(&timer->bg_timer, &timer->expired); + soft_timer_cancel(&timer->phys_timer, NULL); /* * The guest could have modified the timer registers or the timer @@ -497,6 +504,9 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); timer->bg_timer.function = kvm_bg_timer_expire; + hrtimer_init(&timer->phys_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + timer->phys_timer.function = kvm_phys_timer_expire; + vtimer->irq.irq = default_vtimer_irq.irq; ptimer->irq.irq = default_ptimer_irq.irq; } @@ -605,6 +615,7 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) struct arch_timer_context *vtimer = vcpu_vtimer(vcpu); soft_timer_cancel(&timer->bg_timer, &timer->expired); + soft_timer_cancel(&timer->phys_timer, NULL); kvm_vgic_unmap_phys_irq(vcpu, vtimer->irq.irq); } -- 2.14.2
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 10/20] KVM: arm/arm64: Use separate timer for phys timer emulation Date: Fri, 20 Oct 2017 13:49:29 +0200 [thread overview] Message-ID: <20171020114939.12554-11-christoffer.dall@linaro.org> (raw) In-Reply-To: <20171020114939.12554-1-christoffer.dall@linaro.org> From: Christoffer Dall <cdall@linaro.org> We were using the same hrtimer for emulating the physical timer and for making sure a blocking VCPU thread would be eventually woken up. That worked fine in the previous arch timer design, but as we are about to actually use the soft timer expire function for the physical timer emulation, change the logic to use a dedicated hrtimer. This has the added benefit of not having to cancel any work in the sync path, which in turn allows us to run the flush and sync with IRQs disabled. Note that the hrtimer used to program the host kernel's timer to generate an exit from the guest when the emulated physical timer fires never has to inject any work, and to share the soft_timer_cancel() function with the bg_timer, we change the function to only cancel any pending work if the pointer to the work struct is not null. Signed-off-by: Christoffer Dall <cdall@linaro.org> --- Notes: Changes since v3: - Check if the work struct pointer is null in soft_timer_cancel() - Moved after we run flush/sync with disabled IRQs to ensure the hrtimer handler doesn't fire. include/kvm/arm_arch_timer.h | 3 +++ virt/kvm/arm/arch_timer.c | 21 ++++++++++++++++----- 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 0eed5bc9fd5e..184c3ef2df93 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -48,6 +48,9 @@ struct arch_timer_cpu { /* Work queued with the above timer expires */ struct work_struct expired; + /* Physical timer emulation */ + struct hrtimer phys_timer; + /* Is the timer enabled */ bool enabled; }; diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 8ec392850e69..4ad853737c34 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -65,7 +65,8 @@ static void soft_timer_start(struct hrtimer *hrt, u64 ns) static void soft_timer_cancel(struct hrtimer *hrt, struct work_struct *work) { hrtimer_cancel(hrt); - cancel_work_sync(work); + if (work) + cancel_work_sync(work); } static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) @@ -172,6 +173,12 @@ static enum hrtimer_restart kvm_bg_timer_expire(struct hrtimer *hrt) return HRTIMER_NORESTART; } +static enum hrtimer_restart kvm_phys_timer_expire(struct hrtimer *hrt) +{ + WARN(1, "Timer only used to ensure guest exit - unexpected event."); + return HRTIMER_NORESTART; +} + bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx) { u64 cval, now; @@ -249,7 +256,7 @@ static void kvm_timer_update_state(struct kvm_vcpu *vcpu) } /* Schedule the background timer for the emulated timer. */ -static void kvm_timer_emulate(struct kvm_vcpu *vcpu, +static void phys_timer_emulate(struct kvm_vcpu *vcpu, struct arch_timer_context *timer_ctx) { struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; @@ -261,7 +268,7 @@ static void kvm_timer_emulate(struct kvm_vcpu *vcpu, return; /* The timer has not yet expired, schedule a background timer */ - soft_timer_start(&timer->bg_timer, kvm_timer_compute_delta(timer_ctx)); + soft_timer_start(&timer->phys_timer, kvm_timer_compute_delta(timer_ctx)); } /* @@ -414,7 +421,7 @@ void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) kvm_timer_update_state(vcpu); /* Set the background timer for the physical timer emulation. */ - kvm_timer_emulate(vcpu, vcpu_ptimer(vcpu)); + phys_timer_emulate(vcpu, vcpu_ptimer(vcpu)); if (unlikely(!irqchip_in_kernel(vcpu->kvm))) kvm_timer_flush_hwstate_user(vcpu); @@ -437,7 +444,7 @@ void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) * This is to cancel the background timer for the physical timer * emulation if it is set. */ - soft_timer_cancel(&timer->bg_timer, &timer->expired); + soft_timer_cancel(&timer->phys_timer, NULL); /* * The guest could have modified the timer registers or the timer @@ -497,6 +504,9 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); timer->bg_timer.function = kvm_bg_timer_expire; + hrtimer_init(&timer->phys_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + timer->phys_timer.function = kvm_phys_timer_expire; + vtimer->irq.irq = default_vtimer_irq.irq; ptimer->irq.irq = default_ptimer_irq.irq; } @@ -605,6 +615,7 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) struct arch_timer_context *vtimer = vcpu_vtimer(vcpu); soft_timer_cancel(&timer->bg_timer, &timer->expired); + soft_timer_cancel(&timer->phys_timer, NULL); kvm_vgic_unmap_phys_irq(vcpu, vtimer->irq.irq); } -- 2.14.2
next prev parent reply other threads:[~2017-10-20 11:49 UTC|newest] Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-20 11:49 [PATCH v4 00/20] KVM: arm/arm64: Optimize arch timer register handling Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 01/20] irqchip/gic: Deal with broken firmware exposing only 4kB of GICv2 CPU interface Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 02/20] arm64: Implement arch_counter_get_cntpct to read the physical counter Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 13:41 ` Marc Zyngier 2017-10-25 13:41 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 03/20] arm64: Use physical counter for in-kernel reads when booted in EL2 Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 13:43 ` Marc Zyngier 2017-10-25 13:43 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 04/20] KVM: arm/arm64: Guard kvm_vgic_map_is_active against !vgic_initialized Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 05/20] KVM: arm/arm64: Support calling vgic_update_irq_pending from irq context Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 13:45 ` Marc Zyngier 2017-10-25 13:45 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 06/20] KVM: arm/arm64: Check that system supports split eoi/deactivate Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 13:47 ` Marc Zyngier 2017-10-25 13:47 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 07/20] KVM: arm/arm64: Make timer_arm and timer_disarm helpers more generic Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 13:49 ` Marc Zyngier 2017-10-25 13:49 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 08/20] KVM: arm/arm64: Rename soft timer to bg_timer Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 09/20] KVM: arm/arm64: Move timer/vgic flush/sync under disabled irq Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall [this message] 2017-10-20 11:49 ` [PATCH v4 10/20] KVM: arm/arm64: Use separate timer for phys timer emulation Christoffer Dall 2017-10-25 13:59 ` Marc Zyngier 2017-10-25 13:59 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 11/20] KVM: arm/arm64: Move timer save/restore out of the hyp code Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 12/20] genirq: Document vcpu_info usage for percpu_devid interrupts Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:56 ` Thomas Gleixner 2017-10-20 11:56 ` Thomas Gleixner 2017-10-21 14:29 ` Christoffer Dall 2017-10-21 14:29 ` Christoffer Dall 2017-10-21 14:55 ` Thomas Gleixner 2017-10-21 14:55 ` Thomas Gleixner 2017-10-21 15:30 ` Christoffer Dall 2017-10-21 15:30 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 13/20] KVM: arm/arm64: Set VCPU affinity for virt timer irq Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 14/20] KVM: arm/arm64: Avoid timer save/restore in vcpu entry/exit Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 14:36 ` Marc Zyngier 2017-10-25 14:36 ` Marc Zyngier 2017-11-16 20:30 ` Jintack Lim 2017-11-16 20:30 ` Jintack Lim 2017-11-16 20:32 ` Jintack Lim 2017-11-16 20:32 ` Jintack Lim 2017-11-20 11:15 ` Christoffer Dall 2017-11-20 11:15 ` Christoffer Dall 2017-11-20 16:32 ` Jintack Lim 2017-11-20 16:32 ` Jintack Lim 2017-10-20 11:49 ` [PATCH v4 15/20] KVM: arm/arm64: Support EL1 phys timer register access in set/get reg Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-25 14:38 ` Marc Zyngier 2017-10-25 14:38 ` Marc Zyngier 2017-10-20 11:49 ` [PATCH v4 16/20] KVM: arm/arm64: Use kvm_arm_timer_set/get_reg for guest register traps Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 17/20] KVM: arm/arm64: Move phys_timer_emulate function Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 18/20] KVM: arm/arm64: Avoid phys timer emulation in vcpu entry/exit Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 19/20] KVM: arm/arm64: Get rid of kvm_timer_flush_hwstate Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall 2017-10-20 11:49 ` [PATCH v4 20/20] KVM: arm/arm64: Rework kvm_timer_should_fire Christoffer Dall 2017-10-20 11:49 ` Christoffer Dall
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20171020114939.12554-11-christoffer.dall@linaro.org \ --to=christoffer.dall@linaro.org \ --cc=cdall@linaro.org \ --cc=kvm@vger.kernel.org \ --cc=kvmarm@lists.cs.columbia.edu \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=marc.zyngier@arm.com \ --cc=shihwei@cs.columbia.edu \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.