[qemu-xen stable-4.19] include/hw/virtio/virtio-gpu: Fix virtio-gpu with blob on big endian hosts

[patchbot@xxxxxxx]

commit f2f8e74ff4eeca352981be4c5fdb03f19e58be7d
Author:     Thomas Huth <thuth@xxxxxxxxxx>
AuthorDate: Tue Aug 15 14:20:07 2023 +0200
Commit:     Michael Tokarev <mjt@xxxxxxxxxx>
CommitDate: Sun Sep 10 19:39:41 2023 +0300

    include/hw/virtio/virtio-gpu: Fix virtio-gpu with blob on big endian hosts
    
    Using "-device virtio-gpu,blob=true" currently does not work on big
    endian hosts (like s390x). The guest kernel prints an error message
    like:
    
     [drm:virtio_gpu_dequeue_ctrl_func [virtio_gpu]] *ERROR* response 0x1200 
(command 0x10c)
    
    and the display stays black. When running QEMU with "-d guest_errors",
    it shows an error message like this:
    
     virtio_gpu_create_mapping_iov: nr_entries is too big (83886080 > 16384)
    
    which indicates that this value has not been properly byte-swapped.
    And indeed, the virtio_gpu_create_blob_bswap() function (that should
    swap the fields in the related structure) fails to swap some of the
    entries. After correctly swapping all missing values here, too, the
    virtio-gpu device is now also working with blob=true on s390x hosts.
    
    Fixes: e0933d91b1 ("virtio-gpu: Add virtio_gpu_resource_create_blob")
    Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2230469
    Message-Id: <20230815122007.928049-1-thuth@xxxxxxxxxx>
    Reviewed-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
    Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
    (cherry picked from commit d194362910138776e8abd6bb3c9fb3693254e95f)
    Signed-off-by: Michael Tokarev <mjt@xxxxxxxxxx>
---
 include/hw/virtio/virtio-gpu-bswap.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/hw/virtio/virtio-gpu-bswap.h 
b/include/hw/virtio/virtio-gpu-bswap.h
index 9124108485..637a0585d0 100644
--- a/include/hw/virtio/virtio-gpu-bswap.h
+++ b/include/hw/virtio/virtio-gpu-bswap.h
@@ -63,7 +63,10 @@ virtio_gpu_create_blob_bswap(struct 
virtio_gpu_resource_create_blob *cblob)
 {
     virtio_gpu_ctrl_hdr_bswap(&cblob->hdr);
     le32_to_cpus(&cblob->resource_id);
+    le32_to_cpus(&cblob->blob_mem);
     le32_to_cpus(&cblob->blob_flags);
+    le32_to_cpus(&cblob->nr_entries);
+    le64_to_cpus(&cblob->blob_id);
     le64_to_cpus(&cblob->size);
 }
 
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