From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EDE3BCA9EAC for ; Sat, 19 Oct 2019 11:28:27 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 738D520869 for ; Sat, 19 Oct 2019 11:28:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 738D520869 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 254C44A99D; Sat, 19 Oct 2019 07:28:26 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id h0ntcq8Dimbe; Sat, 19 Oct 2019 07:28:24 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id CA4C14AA3C; Sat, 19 Oct 2019 07:28:24 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2A8F44AA38 for ; Sat, 19 Oct 2019 07:28:24 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id V1cXgeEI4bK9 for ; Sat, 19 Oct 2019 07:28:22 -0400 (EDT) Received: from inca-roads.misterjones.org (inca-roads.misterjones.org [213.251.177.50]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id CA34D4A99D for ; Sat, 19 Oct 2019 07:28:22 -0400 (EDT) Received: from [185.104.136.17] (helo=big-swifty.misterjones.org) by cheepnis.misterjones.org with esmtpsa (TLSv1.2:AES256-GCM-SHA384:256) (Exim 4.80) (envelope-from ) id 1iLmuB-00071Z-9o; Sat, 19 Oct 2019 13:28:19 +0200 Date: Sat, 19 Oct 2019 12:28:12 +0100 Message-ID: <86d0etynxv.wl-maz@kernel.org> From: Marc Zyngier To: Steven Price Subject: Re: [PATCH v6 07/10] KVM: arm64: Provide VCPU attributes for stolen time In-Reply-To: <20191011125930.40834-8-steven.price@arm.com> References: <20191011125930.40834-1-steven.price@arm.com> <20191011125930.40834-8-steven.price@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 EasyPG/1.0.0 Emacs/26 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.104.136.17 X-SA-Exim-Rcpt-To: steven.price@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, catalin.marinas@arm.com, pbonzini@redhat.com, rkrcmar@redhat.com, linux@armlinux.org.uk, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, mark.rutland@arm.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on cheepnis.misterjones.org); SAEximRunCond expanded to false Cc: kvm@vger.kernel.org, Catalin Marinas , linux-doc@vger.kernel.org, Russell King , linux-kernel@vger.kernel.org, Paolo Bonzini , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Fri, 11 Oct 2019 13:59:27 +0100, Steven Price wrote: > > Allow user space to inform the KVM host where in the physical memory > map the paravirtualized time structures should be located. > > User space can set an attribute on the VCPU providing the IPA base > address of the stolen time structure for that VCPU. This must be > repeated for every VCPU in the VM. > > The address is given in terms of the physical address visible to > the guest and must be 64 byte aligned. The guest will discover the > address via a hypercall. > > Signed-off-by: Steven Price > --- > arch/arm64/include/asm/kvm_host.h | 7 +++++ > arch/arm64/include/uapi/asm/kvm.h | 2 ++ > arch/arm64/kvm/guest.c | 9 ++++++ > include/uapi/linux/kvm.h | 2 ++ > virt/kvm/arm/pvtime.c | 47 +++++++++++++++++++++++++++++++ > 5 files changed, 67 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 1697e63f6dd8..6af16b29a41f 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -489,6 +489,13 @@ long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu); > long kvm_hypercall_stolen_time(struct kvm_vcpu *vcpu); > int kvm_update_stolen_time(struct kvm_vcpu *vcpu, bool init); > > +int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu, > + struct kvm_device_attr *attr); > +int kvm_arm_pvtime_get_attr(struct kvm_vcpu *vcpu, > + struct kvm_device_attr *attr); > +int kvm_arm_pvtime_has_attr(struct kvm_vcpu *vcpu, > + struct kvm_device_attr *attr); > + > static inline void kvm_arm_pvtime_vcpu_init(struct kvm_vcpu_arch *vcpu_arch) > { > vcpu_arch->steal.base = GPA_INVALID; > diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h > index 67c21f9bdbad..cff1ba12c768 100644 > --- a/arch/arm64/include/uapi/asm/kvm.h > +++ b/arch/arm64/include/uapi/asm/kvm.h > @@ -323,6 +323,8 @@ struct kvm_vcpu_events { > #define KVM_ARM_VCPU_TIMER_CTRL 1 > #define KVM_ARM_VCPU_TIMER_IRQ_VTIMER 0 > #define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1 > +#define KVM_ARM_VCPU_PVTIME_CTRL 2 > +#define KVM_ARM_VCPU_PVTIME_IPA 0 > > /* KVM_IRQ_LINE irq field index values */ > #define KVM_ARM_IRQ_VCPU2_SHIFT 28 > diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c > index dfd626447482..d3ac9d2fd405 100644 > --- a/arch/arm64/kvm/guest.c > +++ b/arch/arm64/kvm/guest.c > @@ -858,6 +858,9 @@ int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu, > case KVM_ARM_VCPU_TIMER_CTRL: > ret = kvm_arm_timer_set_attr(vcpu, attr); > break; > + case KVM_ARM_VCPU_PVTIME_CTRL: > + ret = kvm_arm_pvtime_set_attr(vcpu, attr); > + break; > default: > ret = -ENXIO; > break; > @@ -878,6 +881,9 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu, > case KVM_ARM_VCPU_TIMER_CTRL: > ret = kvm_arm_timer_get_attr(vcpu, attr); > break; > + case KVM_ARM_VCPU_PVTIME_CTRL: > + ret = kvm_arm_pvtime_get_attr(vcpu, attr); > + break; > default: > ret = -ENXIO; > break; > @@ -898,6 +904,9 @@ int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu, > case KVM_ARM_VCPU_TIMER_CTRL: > ret = kvm_arm_timer_has_attr(vcpu, attr); > break; > + case KVM_ARM_VCPU_PVTIME_CTRL: > + ret = kvm_arm_pvtime_has_attr(vcpu, attr); > + break; > default: > ret = -ENXIO; > break; > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 52641d8ca9e8..a540c8357049 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1227,6 +1227,8 @@ enum kvm_device_type { > #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS > KVM_DEV_TYPE_XIVE, > #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE > + KVM_DEV_TYPE_ARM_PV_TIME, > +#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME > KVM_DEV_TYPE_MAX, > }; > > diff --git a/virt/kvm/arm/pvtime.c b/virt/kvm/arm/pvtime.c > index a90f1b4ebd13..9dc466861e1e 100644 > --- a/virt/kvm/arm/pvtime.c > +++ b/virt/kvm/arm/pvtime.c > @@ -2,7 +2,9 @@ > // Copyright (C) 2019 Arm Ltd. > > #include > +#include > > +#include > #include > > #include > @@ -75,3 +77,48 @@ long kvm_hypercall_stolen_time(struct kvm_vcpu *vcpu) > > return vcpu->arch.steal.base; > } > + > +int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu, > + struct kvm_device_attr *attr) > +{ > + u64 __user *user = (u64 __user *)attr->addr; > + u64 ipa; > + > + if (attr->attr != KVM_ARM_VCPU_PVTIME_IPA) > + return -ENXIO; > + > + if (get_user(ipa, user)) > + return -EFAULT; > + if (!IS_ALIGNED(ipa, 64)) > + return -EINVAL; > + if (vcpu->arch.steal.base != GPA_INVALID) > + return -EEXIST; > + vcpu->arch.steal.base = ipa; And what if this IPA doesn't point to any memslot? I understand that everything will still work (kvm_put_user()) will handle the mishap, but it makes it hard for userspace to know that something is wrong. Is there any problem in mandating that the corresponding memslot already has been created, and enforcing this check? Thanks, M. -- Jazz is not dead, it just smells funny. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm