From patchwork Mon Sep 18 20:56:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13390483 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 BE15DCD37B0 for ; Mon, 18 Sep 2023 20:57:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230127AbjIRU5T (ORCPT ); Mon, 18 Sep 2023 16:57:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230081AbjIRU5R (ORCPT ); Mon, 18 Sep 2023 16:57:17 -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 265D6111 for ; Mon, 18 Sep 2023 13:56:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695070586; 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=FQDD0pkq9/UtADo9UYzkWMKduX2RKacPnCgn9XTsyXU=; b=PqKP0v+Oa15AecbqrU6RtYUY9gWn1R4i4jght/vVVbCxqeVniEJ6XWXC3u/uA1V5E0Y7F/ v6/D9FnO8l1yQ9u2vwT+O1EK64WSSOldl8dQKOk9GTGG8RlocfhkSwm1Fum9hBbvL/djYh 1tzYfFp9FJPypcj4IsdyUDDh4Q/t/kE= 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-201-a0vd4XBkPZaB3qrBnjW9Nw-1; Mon, 18 Sep 2023 16:56:23 -0400 X-MC-Unique: a0vd4XBkPZaB3qrBnjW9Nw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7456E101A585; Mon, 18 Sep 2023 20:56:23 +0000 (UTC) Received: from localhost (unknown [10.39.195.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id E01D0492B16; Mon, 18 Sep 2023 20:56:22 +0000 (UTC) From: Stefan Hajnoczi To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jason Gunthorpe , Alex Williamson , David Laight , "Tian, Kevin" , Stefan Hajnoczi Subject: [PATCH v3 2/3] vfio: use __aligned_u64 in struct vfio_device_gfx_plane_info Date: Mon, 18 Sep 2023 16:56:16 -0400 Message-ID: <20230918205617.1478722-3-stefanha@redhat.com> In-Reply-To: <20230918205617.1478722-1-stefanha@redhat.com> References: <20230918205617.1478722-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 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 Reviewed-by: Kevin Tian Signed-off-by: Stefan Hajnoczi --- include/uapi/linux/vfio.h | 3 ++- drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +- samples/vfio-mdev/mbochs.c | 2 +- samples/vfio-mdev/mdpy.c | 2 +- 4 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 4dc0182c6bcb..ee98b6d4a112 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 42ce20e72db7..faf21be724c3 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -1379,7 +1379,7 @@ 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, diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index 3764d1911b51..93405264ff23 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); diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index 064e1c0a7aa8..72ea5832c927 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);