From patchwork Tue Apr 12 06:28:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 560557 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F209C43219 for ; Tue, 12 Apr 2022 07:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352022AbiDLHXN (ORCPT ); Tue, 12 Apr 2022 03:23:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353062AbiDLHOr (ORCPT ); Tue, 12 Apr 2022 03:14:47 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D73273298A; Mon, 11 Apr 2022 23:56:02 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8001FB81B35; Tue, 12 Apr 2022 06:56:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5F61C385A1; Tue, 12 Apr 2022 06:55:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649746560; bh=YgdhlSMxeDCviAyj1bNwcZx0pm30/AJOk4lyrViDXrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DYtMInFJ6U1WuTPkvDD+YOsXvI7MA/yJedZIiacWs2rxVqeIbO0AQYaCUzMKl8pl+ nC7nXMISB6v0JNGrcbW3kBmQo6/8HycLW8LUeG6+fIOCjU66tsYSzN/NYUVy0Wpm3+ zwZuRaVH7mbF8fm9pFxIJVpBUcloMm29pk5SQ0gs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Zyngier , Alexandru Elisei , Sasha Levin Subject: [PATCH 5.16 049/285] KVM: arm64: Do not change the PMU event filter after a VCPU has run Date: Tue, 12 Apr 2022 08:28:26 +0200 Message-Id: <20220412062945.088909500@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062943.670770901@linuxfoundation.org> References: <20220412062943.670770901@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Marc Zyngier [ Upstream commit 5177fe91e4cf78a659aada2c9cf712db4d788481 ] Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com Signed-off-by: Sasha Levin --- Documentation/virt/kvm/devices/vcpu.rst | 2 +- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/arm.c | 4 +++ arch/arm64/kvm/pmu-emul.c | 33 +++++++++++++++---------- 4 files changed, 26 insertions(+), 14 deletions(-) diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst index 60a29972d3f1..d063aaee5bb7 100644 --- a/Documentation/virt/kvm/devices/vcpu.rst +++ b/Documentation/virt/kvm/devices/vcpu.rst @@ -70,7 +70,7 @@ irqchip. -ENODEV PMUv3 not supported or GIC not initialized -ENXIO PMUv3 not properly configured or in-kernel irqchip not configured as required prior to calling this attribute - -EBUSY PMUv3 already initialized + -EBUSY PMUv3 already initialized or a VCPU has already run -EINVAL Invalid filter range ======= ====================================================== diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index d016f27af6da..8c7ba346d713 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -137,6 +137,7 @@ struct kvm_arch { /* Memory Tagging Extension enabled for the guest */ bool mte_enabled; + bool ran_once; }; struct kvm_vcpu_fault_info { diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 1eadf9088880..6f3be4d44abe 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -629,6 +629,10 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) if (kvm_vm_is_protected(kvm)) kvm_call_hyp_nvhe(__pkvm_vcpu_init_traps, vcpu); + mutex_lock(&kvm->lock); + kvm->arch.ran_once = true; + mutex_unlock(&kvm->lock); + return ret; } diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index a5e4bbf5e68f..c996fc562da4 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -921,6 +921,8 @@ static bool pmu_irq_is_valid(struct kvm *kvm, int irq) int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) { + struct kvm *kvm = vcpu->kvm; + if (!kvm_vcpu_has_pmu(vcpu)) return -ENODEV; @@ -938,7 +940,7 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) int __user *uaddr = (int __user *)(long)attr->addr; int irq; - if (!irqchip_in_kernel(vcpu->kvm)) + if (!irqchip_in_kernel(kvm)) return -EINVAL; if (get_user(irq, uaddr)) @@ -948,7 +950,7 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) if (!(irq_is_ppi(irq) || irq_is_spi(irq))) return -EINVAL; - if (!pmu_irq_is_valid(vcpu->kvm, irq)) + if (!pmu_irq_is_valid(kvm, irq)) return -EINVAL; if (kvm_arm_pmu_irq_initialized(vcpu)) @@ -963,7 +965,7 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) struct kvm_pmu_event_filter filter; int nr_events; - nr_events = kvm_pmu_event_mask(vcpu->kvm) + 1; + nr_events = kvm_pmu_event_mask(kvm) + 1; uaddr = (struct kvm_pmu_event_filter __user *)(long)attr->addr; @@ -975,12 +977,17 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) filter.action != KVM_PMU_EVENT_DENY)) return -EINVAL; - mutex_lock(&vcpu->kvm->lock); + mutex_lock(&kvm->lock); + + if (kvm->arch.ran_once) { + mutex_unlock(&kvm->lock); + return -EBUSY; + } - if (!vcpu->kvm->arch.pmu_filter) { - vcpu->kvm->arch.pmu_filter = bitmap_alloc(nr_events, GFP_KERNEL_ACCOUNT); - if (!vcpu->kvm->arch.pmu_filter) { - mutex_unlock(&vcpu->kvm->lock); + if (!kvm->arch.pmu_filter) { + kvm->arch.pmu_filter = bitmap_alloc(nr_events, GFP_KERNEL_ACCOUNT); + if (!kvm->arch.pmu_filter) { + mutex_unlock(&kvm->lock); return -ENOMEM; } @@ -991,17 +998,17 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) * events, the default is to allow. */ if (filter.action == KVM_PMU_EVENT_ALLOW) - bitmap_zero(vcpu->kvm->arch.pmu_filter, nr_events); + bitmap_zero(kvm->arch.pmu_filter, nr_events); else - bitmap_fill(vcpu->kvm->arch.pmu_filter, nr_events); + bitmap_fill(kvm->arch.pmu_filter, nr_events); } if (filter.action == KVM_PMU_EVENT_ALLOW) - bitmap_set(vcpu->kvm->arch.pmu_filter, filter.base_event, filter.nevents); + bitmap_set(kvm->arch.pmu_filter, filter.base_event, filter.nevents); else - bitmap_clear(vcpu->kvm->arch.pmu_filter, filter.base_event, filter.nevents); + bitmap_clear(kvm->arch.pmu_filter, filter.base_event, filter.nevents); - mutex_unlock(&vcpu->kvm->lock); + mutex_unlock(&kvm->lock); return 0; }