From patchwork Fri Jan 5 09:13:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yan Zhao X-Patchwork-Id: 13511889 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E622524B3A; Fri, 5 Jan 2024 09:43:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ZoIf+xOC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1704447790; x=1735983790; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=yLRKvEWofDO1K6stvr9i2IomNOvR/08Zs5+c4O/ibFk=; b=ZoIf+xOCUja/+xF6xyOHlmjoliHWOoFCtn9VtwXxc1nrttUKQz7wnTKt ePIytw3QiiMdUiiu6YH3SeX4krUlFxmjnwEyLwJXMZbCYgwFJcgR+eRdX FlMVlwqictEQ8be4FDr/FQE9+XGB5BwSTMPk+Nygqcx6Vk+6E1FOoqRcK aHcqxXPRM9bmjK/ef7HhTRYYpvnS3m5kVxKJp6jZneecv1mUHl59JEwE7 TP9cPzq0E0y6tYSoHkU6X2wP0VSD7jHcDDGbcv6aakpHGNxZl8TqGAPvC C47RzxDfIPf6dOxgV84xnwlXaljEd/QEc3pp39FHhXJQqnSYQ8LvWTI95 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10943"; a="401260554" X-IronPort-AV: E=Sophos;i="6.04,333,1695711600"; d="scan'208";a="401260554" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jan 2024 01:43:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10943"; a="814920081" X-IronPort-AV: E=Sophos;i="6.04,333,1695711600"; d="scan'208";a="814920081" Received: from yzhao56-desk.sh.intel.com ([10.239.159.62]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jan 2024 01:43:03 -0800 From: Yan Zhao To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: pbonzini@redhat.com, seanjc@google.com, olvaffe@gmail.com, kevin.tian@intel.com, zhiyuan.lv@intel.com, zhenyu.z.wang@intel.com, yongwei.ma@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, gurchetansingh@chromium.org, kraxel@redhat.com, zzyiwei@google.com, ankita@nvidia.com, jgg@nvidia.com, alex.williamson@redhat.com, maz@kernel.org, oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, Yan Zhao , Zhenyu Wang Subject: [PATCH 1/4] KVM: Introduce a new memslot flag KVM_MEM_NON_COHERENT_DMA Date: Fri, 5 Jan 2024 17:13:46 +0800 Message-Id: <20240105091346.24637-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20240105091237.24577-1-yan.y.zhao@intel.com> References: <20240105091237.24577-1-yan.y.zhao@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Introduce a new flag KVM_MEM_NON_COHERENT_DMA to provide user space a channel to notify KVM that guest memory specified by the memslot may be accessed by noncoherent DMA devices. KVM can start honoring guest memory type for this range of guest memory in platforms that do not always honoring guest PAT, e.g. in Intel's platform. Previously, the only way to let KVM be aware of noncoherent DMA devices is through KVM device for VFIO pass-through devices, in which case, KVM is notified that all guest memory may be accessed by noncoherent DMA devices. To avoid complication, flag KVM_MEM_NON_COHERENT_DMA is not allowed to be dynamically modified for a memslot. A KVM_CAP_USER_CONFIGURE_NONCOHERENT_DMA is added to let user space know if this new memslot flag is supported in KVM. Cc: Kevin Tian Cc: Zhenyu Wang Tested-by: Yongwei Ma Signed-off-by: Yan Zhao --- include/uapi/linux/kvm.h | 2 ++ virt/kvm/kvm_main.c | 8 ++++++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index b1f92a0edc35..4cb615e46488 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -46,6 +46,7 @@ struct kvm_userspace_memory_region2 { #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) #define KVM_MEM_READONLY (1UL << 1) #define KVM_MEM_GUEST_MEMFD (1UL << 2) +#define KVM_MEM_NON_COHERENT_DMA (1UL << 3) /* for KVM_IRQ_LINE */ struct kvm_irq_level { @@ -1155,6 +1156,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_MEMORY_ATTRIBUTES 233 #define KVM_CAP_GUEST_MEMFD 234 #define KVM_CAP_VM_TYPES 235 +#define KVM_CAP_USER_CONFIGURE_NONCOHERENT_DMA 236 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index acd67fb40183..6d44dcf7322d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1607,7 +1607,7 @@ static void kvm_replace_memslot(struct kvm *kvm, * only allows these. */ #define KVM_SET_USER_MEMORY_REGION_V1_FLAGS \ - (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY) + (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY | KVM_MEM_NON_COHERENT_DMA) static int check_memory_region_flags(struct kvm *kvm, const struct kvm_userspace_memory_region2 *mem) @@ -1625,6 +1625,8 @@ static int check_memory_region_flags(struct kvm *kvm, valid_flags |= KVM_MEM_READONLY; #endif + valid_flags |= KVM_MEM_NON_COHERENT_DMA; + if (mem->flags & ~valid_flags) return -EINVAL; @@ -2095,7 +2097,8 @@ int __kvm_set_memory_region(struct kvm *kvm, return -EINVAL; if ((mem->userspace_addr != old->userspace_addr) || (npages != old->npages) || - ((mem->flags ^ old->flags) & KVM_MEM_READONLY)) + ((mem->flags ^ old->flags) & + (KVM_MEM_READONLY | KVM_MEM_NON_COHERENT_DMA))) return -EINVAL; if (base_gfn != old->base_gfn) @@ -4822,6 +4825,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) case KVM_CAP_USER_MEMORY2: case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS: + case KVM_CAP_USER_CONFIGURE_NONCOHERENT_DMA: case KVM_CAP_INTERNAL_ERROR_DATA: #ifdef CONFIG_HAVE_KVM_MSI case KVM_CAP_SIGNAL_MSI: