From patchwork Tue Aug 29 18:27:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13369461 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 A1A9AC83F12 for ; Tue, 29 Aug 2023 18:30:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238097AbjH2S3v (ORCPT ); Tue, 29 Aug 2023 14:29:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238098AbjH2S3X (ORCPT ); Tue, 29 Aug 2023 14:29:23 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0E8D19F for ; Tue, 29 Aug 2023 11:27:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693333677; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Mk1FOmX7wMonn07S4mKNEYI4AkKcNYnYkjDJ92TTAB0=; b=YgMalnJpj4U7x+m06p1YlCt0W6IluueKo1Yn4yhbaEmE5EvYSWLXWEj5RYtqRmJ5/fdWwX GEk91QteqKrKFMuyAHEv0GL21EJs3g2hnOInVAYKFaaZGRYuU9wfI2GJbRuuH3in+o8C10 Vdd8t99Y29HUoyo3cRsxmka1reRIBeI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-679-zSRMaMgfO4WdjIbmAU4BMw-1; Tue, 29 Aug 2023 14:27:53 -0400 X-MC-Unique: zSRMaMgfO4WdjIbmAU4BMw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4A7DD101AA4E; Tue, 29 Aug 2023 18:27:53 +0000 (UTC) Received: from localhost (unknown [10.39.192.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id C17C240C6F4C; Tue, 29 Aug 2023 18:27:52 +0000 (UTC) From: Stefan Hajnoczi To: kvm@vger.kernel.org Cc: David Laight , linux-kernel@vger.kernel.org, "Tian, Kevin" , Alex Williamson , Jason Gunthorpe , Stefan Hajnoczi , Jason Gunthorpe Subject: [PATCH v2 1/3] vfio: trivially use __aligned_u64 for ioctl structs Date: Tue, 29 Aug 2023 14:27:18 -0400 Message-ID: <20230829182720.331083-2-stefanha@redhat.com> In-Reply-To: <20230829182720.331083-1-stefanha@redhat.com> References: <20230829182720.331083-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org u64 alignment behaves differently depending on the architecture and so offers __aligned_u64 to achieve consistent behavior in kernel<->userspace ABIs. There are structs in that can trivially be updated to __aligned_u64 because the struct sizes are multiples of 8 bytes. There is no change in memory layout on any CPU architecture and therefore this change is safe. The commits that follow this one handle the trickier cases where explanation about ABI breakage is necessary. Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Kevin Tian --- include/uapi/linux/vfio.h | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index f9c6f3e2cf6e..94007ca348ed 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -277,8 +277,8 @@ struct vfio_region_info { #define VFIO_REGION_INFO_FLAG_CAPS (1 << 3) /* Info supports caps */ __u32 index; /* Region index */ __u32 cap_offset; /* Offset within info struct of first cap */ - __u64 size; /* Region size (bytes) */ - __u64 offset; /* Region offset from start of device fd */ + __aligned_u64 size; /* Region size (bytes) */ + __aligned_u64 offset; /* Region offset from start of device fd */ }; #define VFIO_DEVICE_GET_REGION_INFO _IO(VFIO_TYPE, VFIO_BASE + 8) @@ -294,8 +294,8 @@ struct vfio_region_info { #define VFIO_REGION_INFO_CAP_SPARSE_MMAP 1 struct vfio_region_sparse_mmap_area { - __u64 offset; /* Offset of mmap'able area within region */ - __u64 size; /* Size of mmap'able area */ + __aligned_u64 offset; /* Offset of mmap'able area within region */ + __aligned_u64 size; /* Size of mmap'able area */ }; struct vfio_region_info_cap_sparse_mmap { @@ -450,9 +450,9 @@ struct vfio_device_migration_info { VFIO_DEVICE_STATE_V1_RESUMING) __u32 reserved; - __u64 pending_bytes; - __u64 data_offset; - __u64 data_size; + __aligned_u64 pending_bytes; + __aligned_u64 data_offset; + __aligned_u64 data_size; }; /* @@ -476,7 +476,7 @@ struct vfio_device_migration_info { struct vfio_region_info_cap_nvlink2_ssatgt { struct vfio_info_cap_header header; - __u64 tgt; + __aligned_u64 tgt; }; /* @@ -1443,7 +1443,7 @@ struct vfio_iommu_type1_info { __u32 flags; #define VFIO_IOMMU_INFO_PGSIZES (1 << 0) /* supported page sizes info */ #define VFIO_IOMMU_INFO_CAPS (1 << 1) /* Info supports caps */ - __u64 iova_pgsizes; /* Bitmap of supported page sizes */ + __aligned_u64 iova_pgsizes; /* Bitmap of supported page sizes */ __u32 cap_offset; /* Offset within info struct of first cap */ __u32 pad; }; From patchwork Tue Aug 29 18:27:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13369460 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 A6B24C83F18 for ; Tue, 29 Aug 2023 18:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238052AbjH2S2p (ORCPT ); Tue, 29 Aug 2023 14:28:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237940AbjH2S2g (ORCPT ); Tue, 29 Aug 2023 14:28:36 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF4C6110 for ; 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Tue, 29 Aug 2023 18:27:42 +0000 (UTC) Received: from localhost (unknown [10.39.192.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id A4793C15BAE; Tue, 29 Aug 2023 18:27:41 +0000 (UTC) From: Stefan Hajnoczi To: kvm@vger.kernel.org Cc: David Laight , linux-kernel@vger.kernel.org, "Tian, Kevin" , Alex Williamson , Jason Gunthorpe , Stefan Hajnoczi Subject: [PATCH v2 2/3] vfio: use __aligned_u64 in struct vfio_device_gfx_plane_info Date: Tue, 29 Aug 2023 14:27:19 -0400 Message-ID: <20230829182720.331083-3-stefanha@redhat.com> In-Reply-To: <20230829182720.331083-1-stefanha@redhat.com> References: <20230829182720.331083-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The memory layout of struct vfio_device_gfx_plane_info is architecture-dependent due to a u64 field and a struct size that is not a multiple of 8 bytes: - On x86_64 the struct size is padded to a multiple of 8 bytes. - On x32 the struct size is only a multiple of 4 bytes, not 8. - Other architectures may vary. Use __aligned_u64 to make memory layout consistent. This reduces the chance of 32-bit userspace on a 64-bit kernel breakage. This patch increases the struct size on x32 but this is safe because of the struct's argsz field. The kernel may grow the struct as long as it still supports smaller argsz values from userspace (e.g. applications compiled against older kernel headers). Suggested-by: Jason Gunthorpe Signed-off-by: Stefan Hajnoczi Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian --- include/uapi/linux/vfio.h | 3 ++- drivers/gpu/drm/i915/gvt/kvmgt.c | 4 +++- samples/vfio-mdev/mbochs.c | 6 ++++-- samples/vfio-mdev/mdpy.c | 4 +++- 4 files changed, 12 insertions(+), 5 deletions(-) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 94007ca348ed..777374dd7725 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -816,7 +816,7 @@ struct vfio_device_gfx_plane_info { __u32 drm_plane_type; /* type of plane: DRM_PLANE_TYPE_* */ /* out */ __u32 drm_format; /* drm format of plane */ - __u64 drm_format_mod; /* tiled mode */ + __aligned_u64 drm_format_mod; /* tiled mode */ __u32 width; /* width of plane */ __u32 height; /* height of plane */ __u32 stride; /* stride of plane */ @@ -829,6 +829,7 @@ struct vfio_device_gfx_plane_info { __u32 region_index; /* region index */ __u32 dmabuf_id; /* dma-buf id */ }; + __u32 reserved; }; #define VFIO_DEVICE_QUERY_GFX_PLANE _IO(VFIO_TYPE, VFIO_BASE + 14) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 9cd9e9da60dd..813cfef23453 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -1382,7 +1382,7 @@ static long intel_vgpu_ioctl(struct vfio_device *vfio_dev, unsigned int cmd, intel_gvt_reset_vgpu(vgpu); return 0; } else if (cmd == VFIO_DEVICE_QUERY_GFX_PLANE) { - struct vfio_device_gfx_plane_info dmabuf; + struct vfio_device_gfx_plane_info dmabuf = {}; int ret = 0; minsz = offsetofend(struct vfio_device_gfx_plane_info, @@ -1392,6 +1392,8 @@ static long intel_vgpu_ioctl(struct vfio_device *vfio_dev, unsigned int cmd, if (dmabuf.argsz < minsz) return -EINVAL; + minsz = min(dmabuf.argsz, sizeof(dmabuf)); + ret = intel_vgpu_query_plane(vgpu, &dmabuf); if (ret != 0) return ret; diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index 3764d1911b51..78aa977ae597 100644 --- a/samples/vfio-mdev/mbochs.c +++ b/samples/vfio-mdev/mbochs.c @@ -1262,7 +1262,7 @@ static long mbochs_ioctl(struct vfio_device *vdev, unsigned int cmd, case VFIO_DEVICE_QUERY_GFX_PLANE: { - struct vfio_device_gfx_plane_info plane; + struct vfio_device_gfx_plane_info plane = {}; minsz = offsetofend(struct vfio_device_gfx_plane_info, region_index); @@ -1273,11 +1273,13 @@ static long mbochs_ioctl(struct vfio_device *vdev, unsigned int cmd, if (plane.argsz < minsz) return -EINVAL; + outsz = min_t(unsigned long, plane.argsz, sizeof(plane)); + ret = mbochs_query_gfx_plane(mdev_state, &plane); if (ret) return ret; - if (copy_to_user((void __user *)arg, &plane, minsz)) + if (copy_to_user((void __user *)arg, &plane, outsz)) return -EFAULT; return 0; diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index 064e1c0a7aa8..f5c2effc1cec 100644 --- a/samples/vfio-mdev/mdpy.c +++ b/samples/vfio-mdev/mdpy.c @@ -591,7 +591,7 @@ static long mdpy_ioctl(struct vfio_device *vdev, unsigned int cmd, case VFIO_DEVICE_QUERY_GFX_PLANE: { - struct vfio_device_gfx_plane_info plane; + struct vfio_device_gfx_plane_info plane = {}; minsz = offsetofend(struct vfio_device_gfx_plane_info, region_index); @@ -602,6 +602,8 @@ static long mdpy_ioctl(struct vfio_device *vdev, unsigned int cmd, if (plane.argsz < minsz) return -EINVAL; + minsz = min_t(unsigned long, plane.argsz, sizeof(plane)); + ret = mdpy_query_gfx_plane(mdev_state, &plane); if (ret) return ret; From patchwork Tue Aug 29 18:27:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13369458 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 5E629C71153 for ; Tue, 29 Aug 2023 18:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238005AbjH2S2o (ORCPT ); Tue, 29 Aug 2023 14:28:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237942AbjH2S2g (ORCPT ); Tue, 29 Aug 2023 14:28:36 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 758D410E for ; 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Tue, 29 Aug 2023 18:27:44 +0000 (UTC) Received: from localhost (unknown [10.39.192.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id 794641678B; Tue, 29 Aug 2023 18:27:43 +0000 (UTC) From: Stefan Hajnoczi To: kvm@vger.kernel.org Cc: David Laight , linux-kernel@vger.kernel.org, "Tian, Kevin" , Alex Williamson , Jason Gunthorpe , Stefan Hajnoczi , Jason Gunthorpe Subject: [PATCH v2 3/3] vfio: use __aligned_u64 in struct vfio_device_ioeventfd Date: Tue, 29 Aug 2023 14:27:20 -0400 Message-ID: <20230829182720.331083-4-stefanha@redhat.com> In-Reply-To: <20230829182720.331083-1-stefanha@redhat.com> References: <20230829182720.331083-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The memory layout of struct vfio_device_ioeventfd is architecture-dependent due to a u64 field and a struct size that is not a multiple of 8 bytes: - On x86_64 the struct size is padded to a multiple of 8 bytes. - On x32 the struct size is only a multiple of 4 bytes, not 8. - Other architectures may vary. Use __aligned_u64 to make memory layout consistent. This reduces the chance that 32-bit userspace on a 64-bit kernel breakage. This patch increases the struct size on x32 but this is safe because of the struct's argsz field. The kernel may grow the struct as long as it still supports smaller argsz values from userspace (e.g. applications compiled against older kernel headers). The code that uses struct vfio_device_ioeventfd already works correctly when the struct size grows, so only the struct definition needs to be changed. Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Signed-off-by: Stefan Hajnoczi Reviewed-by: Kevin Tian --- include/uapi/linux/vfio.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 777374dd7725..032e41b56506 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -864,9 +864,10 @@ struct vfio_device_ioeventfd { #define VFIO_DEVICE_IOEVENTFD_32 (1 << 2) /* 4-byte write */ #define VFIO_DEVICE_IOEVENTFD_64 (1 << 3) /* 8-byte write */ #define VFIO_DEVICE_IOEVENTFD_SIZE_MASK (0xf) - __u64 offset; /* device fd offset of write */ - __u64 data; /* data to be written */ + __aligned_u64 offset; /* device fd offset of write */ + __aligned_u64 data; /* data to be written */ __s32 fd; /* -1 for de-assignment */ + __u32 reserved; }; #define VFIO_DEVICE_IOEVENTFD _IO(VFIO_TYPE, VFIO_BASE + 16)