In addition to memfd, a blob resource can also have its backing storage in a VFIO device region. Therefore, we first need to figure out if the blob is backed by a VFIO device region or a memfd before we can call the right API to get a dmabuf fd created.
So, once we have the ramblock and the associated mr, we rely on memory_region_is_ram_device() to tell us where the backing storage is located. If the blob resource is VFIO backed, we try to find the right VFIO device that contains the blob and then invoke the API vfio_device_create_dmabuf(). Note that in virtio_gpu_remap_udmabuf(), we first try to test if the VFIO dmabuf exporter supports mmap or not. If it doesn't, we use the VFIO device fd directly to create the CPU mapping. 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/Kconfig | 5 ++ hw/display/virtio-gpu-dmabuf.c | 114 +++++++++++++++++++++++++++++++-- 2 files changed, 112 insertions(+), 7 deletions(-) diff --git a/hw/display/Kconfig b/hw/display/Kconfig index 1e95ab28ef..0d090f25f5 100644 --- a/hw/display/Kconfig +++ b/hw/display/Kconfig @@ -106,6 +106,11 @@ config VIRTIO_VGA depends on VIRTIO_PCI select VGA +config VIRTIO_GPU_VFIO_BLOB + bool + default y + depends on VFIO + config VHOST_USER_GPU bool default y diff --git a/hw/display/virtio-gpu-dmabuf.c b/hw/display/virtio-gpu-dmabuf.c index 80143034d4..940b0e0411 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" @@ -52,6 +53,19 @@ static bool qemu_iovec_same_memory_regions(const struct iovec *iov, int iov_cnt) return true; } +static void vfio_create_dmabuf(VFIODevice *vdev, + struct virtio_gpu_simple_resource *res) +{ +#if defined(VIRTIO_GPU_VFIO_BLOB) + res->dmabuf_fd = vfio_device_create_dmabuf_fd(vdev, res->iov, res->iov_cnt); + if (res->dmabuf_fd < 0) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: VFIO_DEVICE_FEATURE_DMA_BUF: %s\n", + __func__, strerror(errno)); + } +#endif +} + static void virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res) { struct udmabuf_create_list *list; @@ -93,11 +107,69 @@ static void virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res) g_free(list); } -static void virtio_gpu_remap_dmabuf(struct virtio_gpu_simple_resource *res) +static void *vfio_dmabuf_mmap(struct virtio_gpu_simple_resource *res, + VFIODevice *vdev) +{ + struct vfio_region_info *info = NULL; + ram_addr_t offset, len = 0; + void *map, *submap; + int i, ret = -1; + RAMBlock *rb; + + /* + * We first reserve a contiguous chunk of address space for the entire + * dmabuf, then replace it with smaller mappings that correspond to the + * individual segments of the dmabuf. + */ + map = mmap(NULL, res->blob_size, PROT_READ, MAP_SHARED, vdev->fd, 0); + if (map == MAP_FAILED) { + return map; + } + + for (i = 0; i < res->iov_cnt; i++) { + rb = qemu_ram_block_from_host(res->iov[i].iov_base, false, &offset); + if (!rb) { + goto err; + } +#if defined(VIRTIO_GPU_VFIO_BLOB) + ret = vfio_get_region_index_from_mr(rb->mr); + if (ret < 0) { + goto err; + } + + ret = vfio_device_get_region_info(vdev, ret, &info); +#endif + if (ret < 0 || !info) { + goto err; + } + + submap = mmap(map + len, res->iov[i].iov_len, PROT_READ, + MAP_SHARED | MAP_FIXED, vdev->fd, + info->offset + offset); + if (submap == MAP_FAILED) { + goto err; + } + + len += res->iov[i].iov_len; + } + return map; +err: + munmap(map, res->blob_size); + return MAP_FAILED; +} + +static void virtio_gpu_remap_dmabuf(struct virtio_gpu_simple_resource *res, + VFIODevice *vdev) { res->remapped = mmap(NULL, res->blob_size, PROT_READ, MAP_SHARED, res->dmabuf_fd, 0); if (res->remapped == MAP_FAILED) { + if (vdev) { + res->remapped = vfio_dmabuf_mmap(res, vdev); + if (res->remapped != MAP_FAILED) { + return; + } + } warn_report("%s: dmabuf mmap failed: %s", __func__, strerror(errno)); res->remapped = NULL; @@ -155,7 +227,10 @@ bool virtio_gpu_have_udmabuf(void) void virtio_gpu_init_dmabuf(struct virtio_gpu_simple_resource *res) { + VFIODevice *vdev = NULL; void *pdata = NULL; + ram_addr_t offset; + RAMBlock *rb; res->dmabuf_fd = -1; if (res->iov_cnt == 1 && @@ -166,11 +241,38 @@ void virtio_gpu_init_dmabuf(struct virtio_gpu_simple_resource *res) return; } - virtio_gpu_create_udmabuf(res); - if (res->dmabuf_fd < 0) { + rb = qemu_ram_block_from_host(res->iov[0].iov_base, false, &offset); + if (memory_region_is_ram_device(rb->mr)) { + vdev = vfio_device_lookup(rb->mr); + if (!vdev) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Could not find device to create dmabuf\n", + __func__); + return; + } + + vfio_create_dmabuf(vdev, res); + if (res->dmabuf_fd < 0) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Could not create dmabuf from vfio device\n", + __func__); + return; + } + } else if (memory_region_is_ram(rb->mr)) { + virtio_gpu_create_udmabuf(res); + if (res->dmabuf_fd < 0) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Could not create dmabuf from memfd\n", + __func__); + return; + } + } else { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: memory region cannot be used to create dmabuf\n", + __func__); return; } - virtio_gpu_remap_dmabuf(res); + virtio_gpu_remap_dmabuf(res, vdev); if (!res->remapped) { return; } @@ -182,9 +284,7 @@ void virtio_gpu_init_dmabuf(struct virtio_gpu_simple_resource *res) void virtio_gpu_fini_dmabuf(struct virtio_gpu_simple_resource *res) { - if (res->remapped) { - virtio_gpu_destroy_dmabuf(res); - } + virtio_gpu_destroy_dmabuf(res); } static void virtio_gpu_free_dmabuf(VirtIOGPU *g, VGPUDMABuf *dmabuf) -- 2.50.1
