From patchwork Wed Nov 17 15:38:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 12692966 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 009DBC433F5 for ; Wed, 17 Nov 2021 16:00:51 +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 B46D861B3A for ; Wed, 17 Nov 2021 16:00:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B46D861B3A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=F1VBZpLB+4EEWdBufmXzusAIDnCCRKismhT1IEPVNes=; b=cxAsN2MqPVtbrk rBxoDZbldg4wNiuKrMe9zcjgygIYTyPZkPvnZ9Est4Ow5lT0SWEpD+WV0lQ7l5D1Z5vfcvceO/z5L qIQx/QZMMQ9VvC3HhZOd3AhbRqlwXVsfaIhFebwBCAQPmn6FY7v3mJvs8yMQ4WXeW2u+slWF9j0yi LX0wsbV8nYnZLRmbYexuWabuXQrrwrFhYVDbRml/EV0ZT2ARFe20AaeBxJM91jYAAOfEKNieetRuN nWf0ybRnbKF3HBujKnDxcnIOxIZGxHItestG3KwEO12Wz9UCMtZIO4TwQFgpMLKd7PZ1/b2vUoaKu vSOvqXivsNIRR03g57AA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mnNL8-005aMn-5e; Wed, 17 Nov 2021 15:59:14 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mnN0e-005QGZ-Ir for linux-arm-kernel@lists.infradead.org; Wed, 17 Nov 2021 15:38:07 +0000 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 4193D1FB; Wed, 17 Nov 2021 07:38:04 -0800 (PST) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A49873F5A1; Wed, 17 Nov 2021 07:38:02 -0800 (PST) From: Alexandru Elisei To: maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, will@kernel.org, mark.rutland@arm.com Subject: [RFC PATCH v5 34/38] KVM: arm64: Add an userspace API to stop a VCPU profiling Date: Wed, 17 Nov 2021 15:38:38 +0000 Message-Id: <20211117153842.302159-35-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211117153842.302159-1-alexandru.elisei@arm.com> References: <20211117153842.302159-1-alexandru.elisei@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211117_073804_779170_0C1BCD3B X-CRM114-Status: GOOD ( 17.20 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Add the KVM_ARM_VCPU_SPE_CTRL(KVM_ARM_VCPU_SPE_STOP) VCPU attribute to allow userspace to request that KVM disables profiling for that VCPU. The ioctl does nothing yet. Signed-off-by: Alexandru Elisei --- Documentation/virt/kvm/devices/vcpu.rst | 36 +++++++++++++++++++++++++ arch/arm64/include/uapi/asm/kvm.h | 4 +++ arch/arm64/kvm/spe.c | 23 +++++++++++++--- 3 files changed, 60 insertions(+), 3 deletions(-) diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst index 0ed852315664..2e41928c50b1 100644 --- a/Documentation/virt/kvm/devices/vcpu.rst +++ b/Documentation/virt/kvm/devices/vcpu.rst @@ -271,3 +271,39 @@ Returns: Request initialization of the Statistical Profiling Extension for this VCPU. Must be done after initializaing the in-kernel irqchip and after setting the Profiling Buffer management interrupt number for the VCPU. + +5.3 ATTRIBUTE: KVM_ARM_VCPU_SPE_STOP +------------------------------------ + +:Parameters: in kvm_device_attr.addr the address to the flag that specifies + what KVM should do when the guest enables profiling + +The flag must be exactly one of: + +- KVM_ARM_VCPU_SPE_STOP_TRAP: trap all register accesses and ignore the guest + trying to enable profiling. +- KVM_ARM_VCPU_SPE_STOP_EXIT: exit to userspace when the guest tries to enable + profiling. +- KVM_ARM_VCPU_SPE_RESUME: resume profiling, if it was previously stopped using + this attribute. + +If KVM detects that a vcpu is trying to run with SPE enabled when +KVM_ARM_VCPU_STOP_EXIT is set, KVM_RUN will return without entering the guest +with kvm_run.exit_reason equal to KVM_EXIT_FAIL_ENTRY, and the fail_entry struct +will be zeroed. + +Returns: + + ======= ============================================ + -EAGAIN SPE not initialized + -EFAULT Error accessing the flag + -EINVAL Invalid flag + -ENXIO SPE not supported or not properly configured + ======= ============================================ + +Request that KVM disables SPE for the given vcpu. This can be useful for +migration, which relies on tracking dirty pages by write-protecting memory, but +breaks SPE in the guest as KVM does not handle buffer stage 2 faults. + +The attribute must be set after SPE has been initialized successfully. It can be +set multiple times, with the latest value overwritting the previous one. diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index d4c0b53a5fb2..75a5113f610e 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -371,6 +371,10 @@ struct kvm_arm_copy_mte_tags { #define KVM_ARM_VCPU_SPE_CTRL 3 #define KVM_ARM_VCPU_SPE_IRQ 0 #define KVM_ARM_VCPU_SPE_INIT 1 +#define KVM_ARM_VCPU_SPE_STOP 2 +#define KVM_ARM_VCPU_SPE_STOP_TRAP (1 << 0) +#define KVM_ARM_VCPU_SPE_STOP_EXIT (1 << 1) +#define KVM_ARM_VCPU_SPE_RESUME (1 << 2) /* KVM_IRQ_LINE irq field index values */ #define KVM_ARM_IRQ_VCPU2_SHIFT 28 diff --git a/arch/arm64/kvm/spe.c b/arch/arm64/kvm/spe.c index e856554039a1..95d00d8f4faf 100644 --- a/arch/arm64/kvm/spe.c +++ b/arch/arm64/kvm/spe.c @@ -222,14 +222,14 @@ int kvm_spe_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) if (!kvm_vcpu_supports_spe(vcpu)) return -ENXIO; - if (vcpu->arch.spe.initialized) - return -EBUSY; - switch (attr->attr) { case KVM_ARM_VCPU_SPE_IRQ: { int __user *uaddr = (int __user *)(long)attr->addr; int irq; + if (vcpu->arch.spe.initialized) + return -EBUSY; + if (vcpu->arch.spe.irq_num) return -EBUSY; @@ -250,11 +250,27 @@ int kvm_spe_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) if (!vgic_initialized(vcpu->kvm)) return -ENXIO; + if (vcpu->arch.spe.initialized) + return -EBUSY; + if (kvm_vgic_set_owner(vcpu, vcpu->arch.spe.irq_num, &vcpu->arch.spe)) return -ENXIO; vcpu->arch.spe.initialized = true; return 0; + case KVM_ARM_VCPU_SPE_STOP: { + int __user *uaddr = (int __user *)(long)attr->addr; + int flags; + + if (!vcpu->arch.spe.initialized) + return -EAGAIN; + + if (get_user(flags, uaddr)) + return -EFAULT; + + if (!flags) + return -EINVAL; + } } return -ENXIO; @@ -292,6 +308,7 @@ int kvm_spe_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) switch(attr->attr) { case KVM_ARM_VCPU_SPE_IRQ: case KVM_ARM_VCPU_SPE_INIT: + case KVM_ARM_VCPU_SPE_STOP: return 0; }