In addition to memfd, a blob resource can also have its backing storage in a VFIO device region. Since, there is no effective way to determine where the backing storage is located, we first try to create a dmabuf assuming it is in memfd. If that fails, we try to create a dmabuf assuming it is in VFIO device region.
So, we first call virtio_gpu_create_udmabuf() to check if the blob's backing storage is located in a memfd or not. If it is not, we invoke the vfio_device_create_dmabuf_fd() API which identifies the right VFIO device and eventually creates a dmabuf fd. Note that in virtio_gpu_remap_dmabuf(), we first try to test if the VFIO dmabuf exporter supports mmap or not. If it doesn't, we fall back to the vfio_device_mmap_dmabuf() API to get a mapping created for the dmabuf. Cc: Marc-André Lureau <[email protected]> Cc: Alex Bennée <[email protected]> Cc: Akihiko Odaki <[email protected]> Cc: Dmitry Osipenko <[email protected]> Cc: Alex Williamson <[email protected]> Cc: Cédric Le Goater <[email protected]> Signed-off-by: Vivek Kasireddy <[email protected]> --- hw/display/virtio-gpu-dmabuf.c | 35 +++++++++++++++++++++++++++------- 1 file changed, 28 insertions(+), 7 deletions(-) diff --git a/hw/display/virtio-gpu-dmabuf.c b/hw/display/virtio-gpu-dmabuf.c index b2badfc1bd..533d3d601c 100644 --- a/hw/display/virtio-gpu-dmabuf.c +++ b/hw/display/virtio-gpu-dmabuf.c @@ -74,13 +74,21 @@ static int virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res, static bool virtio_gpu_remap_dmabuf(struct virtio_gpu_simple_resource *res, Error **errp) { + Error *mmap_err = 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"); + error_setg_errno(&mmap_err, errno, "dmabuf mmap failed: "); res->remapped = NULL; - return false; + + if (!vfio_device_mmap_dmabuf(res->iov, res->iov_cnt, &map, + res->blob_size, errp)) { + error_report_err(mmap_err); + return false; + } + error_free(mmap_err); + mmap_err = NULL; } res->remapped = map; return true; @@ -137,7 +145,7 @@ bool virtio_gpu_have_udmabuf(void) void virtio_gpu_init_dmabuf(struct virtio_gpu_simple_resource *res) { - Error *local_err = NULL; + Error *local_err = NULL, *vfio_err = NULL; void *pdata = NULL; int ret; @@ -151,15 +159,28 @@ void virtio_gpu_init_dmabuf(struct virtio_gpu_simple_resource *res) error_prepend(&local_err, "Cannot create dmabuf: "); if (ret == VFIO_DMABUF_CREATE_GUEST_ERROR) { - qemu_log_mask(LOG_GUEST_ERROR, - "Cannot create dmabuf: incompatible memory\n"); - error_free(local_err); - return; + ret = vfio_device_create_dmabuf_fd(res->iov, res->iov_cnt, + &vfio_err); + if (ret > 0) { + error_free(local_err); + local_err = NULL; + goto out; + } + + if (ret == VFIO_DMABUF_CREATE_GUEST_ERROR) { + qemu_log_mask(LOG_GUEST_ERROR, + "Cannot create dmabuf: incompatible memory\n"); + error_free(vfio_err); + error_free(local_err); + return; + } + error_report_err(vfio_err); } error_report_err(local_err); return; } +out: res->dmabuf_fd = ret; if (!virtio_gpu_remap_dmabuf(res, &local_err)) { error_report_err(local_err); -- 2.53.0
