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([2a01:e0a:280:24f0:9db0:474c:ff43:9f5c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43b644addfbsm32238446f8f.3.2026.03.23.10.51.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Mar 2026 10:51:41 -0700 (PDT) Message-ID: Date: Mon, 23 Mar 2026 18:51:41 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v12 09/10] virtio-gpu-dmabuf: Improve error handling with 'Error **' and err enum To: Vivek Kasireddy , qemu-devel@nongnu.org Cc: =?UTF-8?Q?Marc-Andr=C3=A9_Lureau?= , =?UTF-8?Q?Alex_Benn=C3=A9e?= , Akihiko Odaki , Dmitry Osipenko , Alex Williamson References: <20260319052023.2088685-1-vivek.kasireddy@intel.com> <20260319052023.2088685-10-vivek.kasireddy@intel.com> Content-Language: en-US, fr From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= Autocrypt: addr=clg@redhat.com; keydata= xsFNBFu8o3UBEADP+oJVJaWm5vzZa/iLgpBAuzxSmNYhURZH+guITvSySk30YWfLYGBWQgeo 8NzNXBY3cH7JX3/a0jzmhDc0U61qFxVgrPqs1PQOjp7yRSFuDAnjtRqNvWkvlnRWLFq4+U5t yzYe4SFMjFb6Oc0xkQmaK2flmiJNnnxPttYwKBPd98WfXMmjwAv7QfwW+OL3VlTPADgzkcqj 53bfZ4VblAQrq6Ctbtu7JuUGAxSIL3XqeQlAwwLTfFGrmpY7MroE7n9Rl+hy/kuIrb/TO8n0 ZxYXvvhT7OmRKvbYuc5Jze6o7op/bJHlufY+AquYQ4dPxjPPVUT/DLiUYJ3oVBWFYNbzfOrV RxEwNuRbycttMiZWxgflsQoHF06q/2l4ttS3zsV4TDZudMq0TbCH/uJFPFsbHUN91qwwaN/+ gy1j7o6aWMz+Ib3O9dK2M/j/O/Ube95mdCqN4N/uSnDlca3YDEWrV9jO1mUS/ndOkjxa34ia 70FjwiSQAsyIwqbRO3CGmiOJqDa9qNvd2TJgAaS2WCw/TlBALjVQ7AyoPEoBPj31K74Wc4GS Rm+FSch32ei61yFu6ACdZ12i5Edt+To+hkElzjt6db/UgRUeKfzlMB7PodK7o8NBD8outJGS tsL2GRX24QvvBuusJdMiLGpNz3uqyqwzC5w0Fd34E6G94806fwARAQABzSJDw6lkcmljIExl IEdvYXRlciA8Y2xnQHJlZGhhdC5jb20+wsGRBBMBCAA7FiEEoPZlSPBIlev+awtgUaNDx8/7 7KEFAmTLlVECGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgkQUaNDx8/77KG0eg// S0zIzTcxkrwJ/9XgdcvVTnXLVF9V4/tZPfB7sCp8rpDCEseU6O0TkOVFoGWM39sEMiQBSvyY lHrP7p7E/JYQNNLh441MfaX8RJ5Ul3btluLapm8oHp/vbHKV2IhLcpNCfAqaQKdfk8yazYhh EdxTBlzxPcu+78uE5fF4wusmtutK0JG0sAgq0mHFZX7qKG6LIbdLdaQalZ8CCFMKUhLptW71 xe+aNrn7hScBoOj2kTDRgf9CE7svmjGToJzUxgeh9mIkxAxTu7XU+8lmL28j2L5uNuDOq9vl hM30OT+pfHmyPLtLK8+GXfFDxjea5hZLF+2yolE/ATQFt9AmOmXC+YayrcO2ZvdnKExZS1o8 VUKpZgRnkwMUUReaF/mTauRQGLuS4lDcI4DrARPyLGNbvYlpmJWnGRWCDguQ/LBPpbG7djoy k3NlvoeA757c4DgCzggViqLm0Bae320qEc6z9o0X0ePqSU2f7vcuWN49Uhox5kM5L86DzjEQ RHXndoJkeL8LmHx8DM+kx4aZt0zVfCHwmKTkSTQoAQakLpLte7tWXIio9ZKhUGPv/eHxXEoS 0rOOAZ6np1U/xNR82QbF9qr9TrTVI3GtVe7Vxmff+qoSAxJiZQCo5kt0YlWwti2fFI4xvkOi V7lyhOA3+/3oRKpZYQ86Frlo61HU3r6d9wzOwU0EW7yjdQEQALyDNNMw/08/fsyWEWjfqVhW pOOrX2h+z4q0lOHkjxi/FRIRLfXeZjFfNQNLSoL8j1y2rQOs1j1g+NV3K5hrZYYcMs0xhmrZ KXAHjjDx7FW3sG3jcGjFW5Xk4olTrZwFsZVUcP8XZlArLmkAX3UyrrXEWPSBJCXxDIW1hzwp bV/nVbo/K9XBptT/wPd+RPiOTIIRptjypGY+S23HYBDND3mtfTz/uY0Jytaio9GETj+fFis6 TxFjjbZNUxKpwftu/4RimZ7qL+uM1rG1lLWc9SPtFxRQ8uLvLOUFB1AqHixBcx7LIXSKZEFU CSLB2AE4wXQkJbApye48qnZ09zc929df5gU6hjgqV9Gk1rIfHxvTsYltA1jWalySEScmr0iS YBZjw8Nbd7SxeomAxzBv2l1Fk8fPzR7M616dtb3Z3HLjyvwAwxtfGD7VnvINPbzyibbe9c6g LxYCr23c2Ry0UfFXh6UKD83d5ybqnXrEJ5n/t1+TLGCYGzF2erVYGkQrReJe8Mld3iGVldB7 JhuAU1+d88NS3aBpNF6TbGXqlXGF6Yua6n1cOY2Yb4lO/mDKgjXd3aviqlwVlodC8AwI0Sdu jWryzL5/AGEU2sIDQCHuv1QgzmKwhE58d475KdVX/3Vt5I9kTXpvEpfW18TjlFkdHGESM/Jx IqVsqvhAJkalABEBAAHCwV8EGAECAAkFAlu8o3UCGwwACgkQUaNDx8/77KEhwg//WqVopd5k 8hQb9VVdk6RQOCTfo6wHhEqgjbXQGlaxKHoXywEQBi8eULbeMQf5l4+tHJWBxswQ93IHBQjK yKyNr4FXseUI5O20XVNYDJZUrhA4yn0e/Af0IX25d94HXQ5sMTWr1qlSK6Zu79lbH3R57w9j hQm9emQEp785ui3A5U2Lqp6nWYWXz0eUZ0Tad2zC71Gg9VazU9MXyWn749s0nXbVLcLS0yop s302Gf3ZmtgfXTX/W+M25hiVRRKCH88yr6it+OMJBUndQVAA/fE9hYom6t/zqA248j0QAV/p LHH3hSirE1mv+7jpQnhMvatrwUpeXrOiEw1nHzWCqOJUZ4SY+HmGFW0YirWV2mYKoaGO2YBU wYF7O9TI3GEEgRMBIRT98fHa0NPwtlTktVISl73LpgVscdW8yg9Gc82oe8FzU1uHjU8b10lU XOMHpqDDEV9//r4ZhkKZ9C4O+YZcTFu+mvAY3GlqivBNkmYsHYSlFsbxc37E1HpTEaSWsGfA HQoPn9qrDJgsgcbBVc1gkUT6hnxShKPp4PlsZVMNjvPAnr5TEBgHkk54HQRhhwcYv1T2QumQ izDiU6iOrUzBThaMhZO3i927SG2DwWDVzZltKrCMD1aMPvb3NU8FOYRhNmIFR3fcalYr+9gD uVKe8BVz4atMOoktmt0GWTOC8P4= In-Reply-To: <20260319052023.2088685-10-vivek.kasireddy@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 3/19/26 06:15, Vivek Kasireddy wrote: > Make the error handling more robust in virtio_gpu_init_udmabuf() > by introducing 'Error **' parameter to capture errors and using > an enum from VFIO to categorize different errors. This allows for > better error reporting and handling of errors from > virtio_gpu_create_udmabuf() and virtio_gpu_remap_dmabuf(). > > Cc: Marc-André Lureau > Cc: Alex Bennée > Cc: Akihiko Odaki > Cc: Dmitry Osipenko > Cc: Alex Williamson > Cc: Cédric Le Goater > Reviewed-by: Akihiko Odaki > Signed-off-by: Vivek Kasireddy > --- > hw/display/virtio-gpu-dmabuf.c | 67 +++++++++++++++++++++++----------- > 1 file changed, 45 insertions(+), 22 deletions(-) > > diff --git a/hw/display/virtio-gpu-dmabuf.c b/hw/display/virtio-gpu-dmabuf.c > index e35f7714a9..89aa487654 100644 > --- a/hw/display/virtio-gpu-dmabuf.c > +++ b/hw/display/virtio-gpu-dmabuf.c > @@ -18,6 +18,7 @@ > #include "ui/console.h" > #include "hw/virtio/virtio-gpu.h" > #include "hw/virtio/virtio-gpu-pixman.h" > +#include "hw/vfio/vfio-device.h" > #include "trace.h" > #include "system/ramblock.h" > #include "system/hostmem.h" > @@ -27,16 +28,18 @@ > #include "standard-headers/linux/udmabuf.h" > #include "standard-headers/drm/drm_fourcc.h" > > -static void virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res) > +static int virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res, > + Error **errp) > { > g_autofree struct udmabuf_create_list *list = NULL; > RAMBlock *rb; > ram_addr_t offset; > - int udmabuf, i; > + int udmabuf, i, fd; > > udmabuf = udmabuf_fd(); > if (udmabuf < 0) { > - return; > + error_setg(errp, "udmabuf device not available or enabled"); > + return VFIO_DMABUF_CREATE_ERR_UNSPEC; The function virtio_gpu_create_udmabuf() is returning VFIO_DMABUF_* enum values, which is problematic because the function creates a udmabuf, not a VFIO dmabuf. This creates a layering violation. The virtio-gpu-dmabuf code (which handles both udmabuf and VFIO dmabuf creation) is using error codes defined in the VFIO-specific header. Please find another solution. > } > > list = g_malloc0(sizeof(struct udmabuf_create_list) + > @@ -45,7 +48,8 @@ static void virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res) > for (i = 0; i < res->iov_cnt; i++) { > rb = qemu_ram_block_from_host(res->iov[i].iov_base, false, &offset); > if (!rb || rb->fd < 0) { > - return; > + error_setg(errp, "IOV memory address incompatible with udmabuf "); > + return VFIO_DMABUF_CREATE_ERR_INVALID_IOV; > } > > list->list[i].memfd = rb->fd; > @@ -56,22 +60,28 @@ static void virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res) > list->count = res->iov_cnt; > list->flags = UDMABUF_FLAGS_CLOEXEC; > > - res->dmabuf_fd = ioctl(udmabuf, UDMABUF_CREATE_LIST, list); > - if (res->dmabuf_fd < 0) { > - warn_report("%s: UDMABUF_CREATE_LIST: %s", __func__, > - strerror(errno)); > + fd = ioctl(udmabuf, UDMABUF_CREATE_LIST, list); > + if (fd < 0) { > + error_setg_errno(errp, errno, "UDMABUF_CREATE_LIST: ioctl failed"); > + if (errno == EINVAL || errno == EBADFD) { > + return VFIO_DMABUF_CREATE_ERR_INVALID_IOV; > + } > + return VFIO_DMABUF_CREATE_ERR_UNSPEC; > } > + return fd; > } > > -static void virtio_gpu_remap_dmabuf(struct virtio_gpu_simple_resource *res) > +static void *virtio_gpu_remap_dmabuf(struct virtio_gpu_simple_resource *res, > + Error **errp) > { > - res->remapped = mmap(NULL, res->blob_size, PROT_READ, > - MAP_SHARED, res->dmabuf_fd, 0); > - if (res->remapped == MAP_FAILED) { > - warn_report("%s: dmabuf mmap failed: %s", __func__, > - strerror(errno)); > - res->remapped = NULL; > + void *map; > + > + map = mmap(NULL, res->blob_size, PROT_READ, MAP_SHARED, res->dmabuf_fd, 0); > + if (map == MAP_FAILED) { > + error_setg_errno(errp, errno, "dmabuf mmap failed"); > + return NULL; > } > + return map; > } > > static void virtio_gpu_destroy_dmabuf(struct virtio_gpu_simple_resource *res) > @@ -125,22 +135,35 @@ bool virtio_gpu_have_udmabuf(void) > > void virtio_gpu_init_dmabuf(struct virtio_gpu_simple_resource *res) > { > + Error *local_err = NULL; > void *pdata = NULL; > > - res->dmabuf_fd = -1; > if (res->iov_cnt == 1 && > res->iov[0].iov_len < 4096) { > + res->dmabuf_fd = -1; > pdata = res->iov[0].iov_base; > } else { > - virtio_gpu_create_udmabuf(res); > + res->dmabuf_fd = virtio_gpu_create_udmabuf(res, &local_err); > + if (res->dmabuf_fd == VFIO_DMABUF_CREATE_ERR_INVALID_IOV) { > + error_free_or_abort(&local_err); Why not report the error in the QEMU log below ? > + > + qemu_log_mask(LOG_GUEST_ERROR, > + "Cannot create dmabuf: incompatible memory\n"); > + return; > + } else if (res->dmabuf_fd >= 0) { > + pdata = virtio_gpu_remap_dmabuf(res, &local_err); > + if (!pdata) { > + virtio_gpu_destroy_dmabuf(res); > + } > + } else { > + res->dmabuf_fd = -1; > + } > + > if (res->dmabuf_fd < 0) { > + error_report_err(local_err); > return; > } > - virtio_gpu_remap_dmabuf(res); > - if (!res->remapped) { > - return; > - } > - pdata = res->remapped; > + res->remapped = pdata; > } > > res->blob = pdata;