From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 75CA22E611F; Wed, 9 Jul 2025 14:49:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752072590; cv=none; b=gI7PMfk8rpD54VnYspMPc1rqcJsWeITRualaxOLCmgw1e5c1Xwv51ExJZXI1Lb0qcs2y99tnIXsSczfuz8aloO7bBnNOOZZhmYSlVmr9xq36dclKdeDoE5S9hLl141RaCukIxadcSneVA14G6n83OSyD0VzQ+vGNNHV8Y+6/sFE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752072590; c=relaxed/simple; bh=CBaf9D1Y5jz2uqiBK+j/ZZJ39e77o1iEu4tYrP0yisE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aBequ1ZWkHTdZAQxQVQX+kstLEoE3247krkAr3q1slW/qA1lNKjC0GxAVre9UDwoUMaKVgqURXsQd/h7S3fYkQipXiAO78IBp35iVgV1mRSzXZ+LhdUBWk+Ve5wcthW1lxDaWTXokfSM9y8zq4deldolFqRPV1CwC58UU8qpNXQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5D191339; Wed, 9 Jul 2025 07:49:36 -0700 (PDT) Received: from e124191.cambridge.arm.com (e124191.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 62BBD3F694; Wed, 9 Jul 2025 07:49:44 -0700 (PDT) Date: Wed, 9 Jul 2025 15:49:39 +0100 From: Joey Gouly To: Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki Subject: Re: [PATCH v9 14/43] KVM: arm64: Support timers in realm RECs Message-ID: <20250709144939.GA2753450@e124191.cambridge.arm.com> References: <20250611104844.245235-1-steven.price@arm.com> <20250611104844.245235-15-steven.price@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250611104844.245235-15-steven.price@arm.com> Hi Steven, On Wed, Jun 11, 2025 at 11:48:11AM +0100, Steven Price wrote: > The RMM keeps track of the timer while the realm REC is running, but on > exit to the normal world KVM is responsible for handling the timers. > > The RMM doesn't provide a mechanism to set the counter offset, so don't > expose KVM_CAP_COUNTER_OFFSET for a realm VM. > > A later patch adds the support for propagating the timer values from the > exit data structure and calling kvm_realm_timers_update(). > > Reviewed-by: Suzuki K Poulose > Signed-off-by: Steven Price > --- > Changes since v7: > * Hide KVM_CAP_COUNTER_OFFSET for realm guests. > --- > arch/arm64/kvm/arch_timer.c | 48 +++++++++++++++++++++++++++++++++--- > arch/arm64/kvm/arm.c | 2 +- > include/kvm/arm_arch_timer.h | 2 ++ > 3 files changed, 47 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c > index fdbc8beec930..7f8705d6fdf5 100644 > --- a/arch/arm64/kvm/arch_timer.c > +++ b/arch/arm64/kvm/arch_timer.c > @@ -148,6 +148,13 @@ static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval) > > static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset) > { > + struct kvm_vcpu *vcpu = ctxt->vcpu; > + > + if (kvm_is_realm(vcpu->kvm)) { > + WARN_ON(offset); > + return; > + } > + > if (!ctxt->offset.vm_offset) { > WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt)); > return; > @@ -462,6 +469,21 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level, > timer_ctx); > } > > +void kvm_realm_timers_update(struct kvm_vcpu *vcpu) > +{ > + struct arch_timer_cpu *arch_timer = &vcpu->arch.timer_cpu; > + int i; > + > + for (i = 0; i < NR_KVM_EL0_TIMERS; i++) { > + struct arch_timer_context *timer = &arch_timer->timers[i]; > + bool status = timer_get_ctl(timer) & ARCH_TIMER_CTRL_IT_STAT; > + bool level = kvm_timer_irq_can_fire(timer) && status; > + > + if (level != timer->irq.level) > + kvm_timer_update_irq(vcpu, level, timer); > + } > +} > + > /* Only called for a fully emulated timer */ > static void timer_emulate(struct arch_timer_context *ctx) > { > @@ -870,6 +892,8 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu) > if (unlikely(!timer->enabled)) > return; > > + kvm_timer_unblocking(vcpu); > + > get_timer_map(vcpu, &map); > > if (static_branch_likely(&has_gic_active_state)) { > @@ -883,8 +907,6 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu) > kvm_timer_vcpu_load_nogic(vcpu); > } > > - kvm_timer_unblocking(vcpu); > - The change here to move kvm_timer_unblocking() looks unnecessary, as the change to add an early return in kvm_timer_enable() causes timer->enable to never be set to 1. Since it is never set, kvm_timer_vcpu_load() will return early before this call to kvm_timer_unblocking(). Thanks, Joey > timer_restore_state(map.direct_vtimer); > if (map.direct_ptimer) > timer_restore_state(map.direct_ptimer); > @@ -1065,7 +1087,9 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid) > > ctxt->vcpu = vcpu; > > - if (timerid == TIMER_VTIMER) > + if (kvm_is_realm(vcpu->kvm)) > + ctxt->offset.vm_offset = NULL; > + else if (timerid == TIMER_VTIMER) > ctxt->offset.vm_offset = &kvm->arch.timer_data.voffset; > else > ctxt->offset.vm_offset = &kvm->arch.timer_data.poffset; > @@ -1087,13 +1111,19 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid) > void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) > { > struct arch_timer_cpu *timer = vcpu_timer(vcpu); > + u64 cntvoff; > > for (int i = 0; i < NR_KVM_TIMERS; i++) > timer_context_init(vcpu, i); > > + if (kvm_is_realm(vcpu->kvm)) > + cntvoff = 0; > + else > + cntvoff = kvm_phys_timer_read(); > + > /* Synchronize offsets across timers of a VM if not already provided */ > if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &vcpu->kvm->arch.flags)) { > - timer_set_offset(vcpu_vtimer(vcpu), kvm_phys_timer_read()); > + timer_set_offset(vcpu_vtimer(vcpu), cntvoff); > timer_set_offset(vcpu_ptimer(vcpu), 0); > } > > @@ -1633,6 +1663,13 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu) > return -EINVAL; > } > > + /* > + * We don't use mapped IRQs for Realms because the RMI doesn't allow > + * us setting the LR.HW bit in the VGIC. > + */ > + if (vcpu_is_rec(vcpu)) > + return 0; > + > get_timer_map(vcpu, &map); > > ret = kvm_vgic_map_phys_irq(vcpu, > @@ -1764,6 +1801,9 @@ int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm, > if (offset->reserved) > return -EINVAL; > > + if (kvm_is_realm(kvm)) > + return -EINVAL; > + > mutex_lock(&kvm->lock); > > if (!kvm_trylock_all_vcpus(kvm)) { > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 0cdcc2ca4a88..6a5c9be4af2d 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -350,10 +350,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_PTP_KVM: > case KVM_CAP_ARM_SYSTEM_SUSPEND: > case KVM_CAP_IRQFD_RESAMPLE: > - case KVM_CAP_COUNTER_OFFSET: > case KVM_CAP_ARM_WRITABLE_IMP_ID_REGS: > r = 1; > break; > + case KVM_CAP_COUNTER_OFFSET: > case KVM_CAP_SET_GUEST_DEBUG: > r = !kvm_is_realm(kvm); > break; > diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h > index 681cf0c8b9df..f64e317c091b 100644 > --- a/include/kvm/arm_arch_timer.h > +++ b/include/kvm/arm_arch_timer.h > @@ -113,6 +113,8 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); > int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); > int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); > > +void kvm_realm_timers_update(struct kvm_vcpu *vcpu); > + > u64 kvm_phys_timer_read(void); > > void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu); > -- > 2.43.0 >