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=-8.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 9707CC3A5A6 for ; Fri, 30 Aug 2019 10:02:31 +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 6BC3421897 for ; Fri, 30 Aug 2019 10:02:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JgVuX9y5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6BC3421897 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=x23Y0+CHxCNYN01qIcACFb8RkCK0bsxQIqXYPCDVPjU=; b=JgVuX9y59QlAkS Nj+BANuWqk5uBVTKQmpkikbA7/T/mmEWlKjRm8xrX5ujzOJ4yzUTicqbMe21qV3ThufkGHL/1S16O OnbTYVp8rDKsM06cdMHPWYZB7ugu3naEkaGzhkoCfJWyIN1CMRhzc3wP8fFLpQrhu9KJLhc6Is7Mu Rv3HfS5xNRjCJypq1c598bBk+qOp2WdA2UbIQtjXvvRazlMsMRO4TZqxxUpTnwLIev2a/OK47kSwj cYowdbi5zvP37YnluRvlbnNCqjIwoNNJrIq4+iqb0HlTmsVVXLS8csi3CbHk4HICXDtXANt9Y2MTP CXlTk4VGSfecVo/zjRbg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i3dji-0004uL-SB; Fri, 30 Aug 2019 10:02:30 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i3djf-0004tU-Dz for linux-arm-kernel@lists.infradead.org; Fri, 30 Aug 2019 10:02:29 +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 4A7A5344; Fri, 30 Aug 2019 03:02:26 -0700 (PDT) Received: from [10.1.197.61] (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A37183F718; Fri, 30 Aug 2019 03:02:22 -0700 (PDT) Subject: Re: [PATCH v4 07/10] KVM: arm64: Provide VCPU attributes for stolen time To: Steven Price , Will Deacon , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu References: <20190830084255.55113-1-steven.price@arm.com> <20190830084255.55113-8-steven.price@arm.com> From: Marc Zyngier Organization: Approximate Message-ID: <36104ec0-2237-fb0e-376f-ab50c23c6101@kernel.org> Date: Fri, 30 Aug 2019 11:02:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190830084255.55113-8-steven.price@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190830_030227_557161_DFFD8D12 X-CRM114-Status: GOOD ( 21.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , kvm@vger.kernel.org, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Catalin Marinas , Suzuki K Pouloze , linux-doc@vger.kernel.org, Russell King , linux-kernel@vger.kernel.org, James Morse , Paolo Bonzini , Julien Thierry Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 30/08/2019 09:42, 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 9a507716ae2f..bde9f165ad3a 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_SET_IPA 0 > > /* KVM_IRQ_LINE irq field index values */ > #define KVM_ARM_IRQ_TYPE_SHIFT 24 > 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 5e3f12d5359e..265156a984f2 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1222,6 +1222,8 @@ 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 d9d0dbc6994b..7b1834b98a68 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_SET_IPA) > + return -ENXIO; > + > + if (get_user(ipa, user)) > + return -EFAULT; > + if (ipa & 63) nit: Please express this as !IS_ALIGNED(ipa, 64) instead. > + return -EINVAL; > + if (vcpu->arch.steal.base != GPA_INVALID) > + return -EEXIST; > + vcpu->arch.steal.base = ipa; I'm still worried that you end-up not knowing whether the IPA is valid or not at this stage, nor that we check about overlapping vcpus. How do we validate that? I also share Christoffer's concern that the memslot parsing may be expensive on a system with multiple memslots. But maybe that can be solved by adding some caching capabilities to your kvm_put_guest(), should this become a problem. > + return 0; > +} > + > +int kvm_arm_pvtime_get_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_SET_IPA) It is a bit odd that this is using "SET_IPA" as a way to GET it. > + return -ENXIO; > + > + ipa = vcpu->arch.steal.base; > + > + if (put_user(ipa, user)) > + return -EFAULT; > + return 0; > +} > + > +int kvm_arm_pvtime_has_attr(struct kvm_vcpu *vcpu, > + struct kvm_device_attr *attr) > +{ > + switch (attr->attr) { > + case KVM_ARM_VCPU_PVTIME_SET_IPA: > + return 0; > + } > + return -ENXIO; > +} > Thanks, M. -- Jazz is not dead, it just smells funny... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel