[v6 0/2] virtio-gpu: fix error handling and improve consistency

[v6 0/2] virtio-gpu: fix error handling and improve consistency

[Honglei Huang]

This series addresses error handling issues in virtio-gpu and improves
code consistency across the virtio-gpu subsystem.

The first patch fixes a critical bug in virgl_cmd_resource_create_blob()
where an inverted error check causes the function to fail when it should
succeed. This is a standalone bug fix that should be backported.

The second patch improves code consistency by unifying the error checking
style for virtio_gpu_create_mapping_iov() in if-statement contexts across
virtio-gpu files, following the preferred QEMU coding convention.

Changes since v5:
- Reverted changes to virtio-gpu-rutabaga.c to keep CHECK macro usage
  consistent with other error checks in the same file
- Updated patch 2 commit message to clarify that CHECK macro patterns
  in rutabaga.c are intentionally left unchanged

Changes since v4:
- Split the single patch into two separate patches for better clarity
- Separated the critical bug fix from the style consistency improvements
- The bug fix (patch 1) can now be easily identified and backported
- The consistency improvements (patch 2) are clearly marked as cleanup

Changes since v3:
- Extended consistency improvements to virtio-gpu-rutabaga.c
- Changed CHECK(!ret) to CHECK(ret >= 0) and CHECK(!result) to
  CHECK(result >= 0) in rutabaga functions for consistency
- Now covers all virtio-gpu files that use virtio_gpu_create_mapping_iov()

Changes since v2:
- Use 'if (ret < 0)' instead of 'if (ret != 0)' following maintainer's
  feedback on preferred QEMU coding style for error checking functions
  that return 0 on success and negative on error
- Updated all similar usages across virtio-gpu files for consistency
- Expanded scope from single function fix to codebase-wide style consistency

Honglei Huang (2):
  virtio-gpu: fix error handling in virgl_cmd_resource_create_blob
  virtio-gpu: use consistent error checking for
    virtio_gpu_create_mapping_iov

 hw/display/virtio-gpu-virgl.c | 4 ++--
 hw/display/virtio-gpu.c       | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

-- 
2.34.1

[v6 0/2] virtio-gpu: fix error handling and improve consistency

[Honglei Huang]

This series addresses error handling issues in virtio-gpu and improves
code consistency across the virtio-gpu subsystem.

The first patch fixes a critical bug in virgl_cmd_resource_create_blob()
where an inverted error check causes the function to fail when it should
succeed. This is a standalone bug fix that should be backported.

The second patch improves code consistency by unifying the error checking
style for virtio_gpu_create_mapping_iov() in if-statement contexts across
virtio-gpu files, following the preferred QEMU coding convention.

Changes since v5:
- Reverted changes to virtio-gpu-rutabaga.c to keep CHECK macro usage
  consistent with other error checks in the same file
- Updated patch 2 commit message to clarify that CHECK macro patterns
  in rutabaga.c are intentionally left unchanged

Changes since v4:
- Split the single patch into two separate patches for better clarity
- Separated the critical bug fix from the style consistency improvements
- The bug fix (patch 1) can now be easily identified and backported
- The consistency improvements (patch 2) are clearly marked as cleanup

Changes since v3:
- Extended consistency improvements to virtio-gpu-rutabaga.c
- Changed CHECK(!ret) to CHECK(ret >= 0) and CHECK(!result) to
  CHECK(result >= 0) in rutabaga functions for consistency
- Now covers all virtio-gpu files that use virtio_gpu_create_mapping_iov()

Changes since v2:
- Use 'if (ret < 0)' instead of 'if (ret != 0)' following maintainer's
  feedback on preferred QEMU coding style for error checking functions
  that return 0 on success and negative on error
- Updated all similar usages across virtio-gpu files for consistency
- Expanded scope from single function fix to codebase-wide style consistency

Honglei Huang (2):
  virtio-gpu: fix error handling in virgl_cmd_resource_create_blob
  virtio-gpu: use consistent error checking for
    virtio_gpu_create_mapping_iov

 hw/display/virtio-gpu-virgl.c | 4 ++--
 hw/display/virtio-gpu.c       | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

-- 
2.34.1

[v6 1/2] virtio-gpu: fix error handling in virgl_cmd_resource_create_blob

[Honglei Huang]

Fix inverted error check in virgl_cmd_resource_create_blob() that causes
the function to return error when virtio_gpu_create_mapping_iov() succeeds.

virtio_gpu_create_mapping_iov() returns 0 on success and negative values
on error. The check 'if (!ret)' incorrectly treats success (ret=0) as an
error condition, causing the function to fail when it should succeed.

Change the condition to 'if (ret != 0)' to properly detect errors.

Fixes: 7c092f17ccee ("virtio-gpu: Handle resource blob commands")
Signed-off-by: Honglei Huang <honghuan@amd.com>
Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/display/virtio-gpu-virgl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index 94ddc01f91..e60e1059df 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -701,7 +701,7 @@ static void virgl_cmd_resource_create_blob(VirtIOGPU *g,
         ret = virtio_gpu_create_mapping_iov(g, cblob.nr_entries, sizeof(cblob),
                                             cmd, &res->base.addrs,
                                             &res->base.iov, &res->base.iov_cnt);
-        if (!ret) {
+        if (ret != 0) {
             cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
             return;
         }
-- 
2.34.1

[v6 2/2] virtio-gpu: use consistent error checking for virtio_gpu_create_mapping_iov

[Honglei Huang]

Unify error checking style for virtio_gpu_create_mapping_iov() across the
codebase to improve consistency and readability.

virtio_gpu_create_mapping_iov() returns 0 on success and negative values
on error. The original code used inconsistent patterns for checking errors:
- Some used 'if (ret != 0)' in virtio-gpu-virgl.c and virtio-gpu.c
- Some used 'CHECK(!ret, cmd)' in virtio-gpu-rutabaga.c

For if-statement checks, change to 'if (ret < 0)' which is the preferred
QEMU coding convention for functions that return 0 on success and negative
on error. This makes the return value convention immediately clear to code
readers.

For CHECK macro usage in virtio-gpu-rutabaga.c, keep the original
'CHECK(!ret, cmd)' pattern as it is more concise and consistent with other
error checks in the same file.

Updated locations:
- hw/display/virtio-gpu-virgl.c: virgl_resource_attach_backing()
- hw/display/virtio-gpu-virgl.c: virgl_cmd_resource_create_blob()
- hw/display/virtio-gpu.c: virtio_gpu_resource_create_blob()
- hw/display/virtio-gpu.c: virtio_gpu_resource_attach_backing()

Signed-off-by: Honglei Huang <honghuan@amd.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/display/virtio-gpu-virgl.c | 4 ++--
 hw/display/virtio-gpu.c       | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index e60e1059df..6ebd9293e5 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -557,7 +557,7 @@ static void virgl_resource_attach_backing(VirtIOGPU *g,
 
     ret = virtio_gpu_create_mapping_iov(g, att_rb.nr_entries, sizeof(att_rb),
                                         cmd, NULL, &res_iovs, &res_niov);
-    if (ret != 0) {
+    if (ret < 0) {
         cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
         return;
     }
@@ -701,7 +701,7 @@ static void virgl_cmd_resource_create_blob(VirtIOGPU *g,
         ret = virtio_gpu_create_mapping_iov(g, cblob.nr_entries, sizeof(cblob),
                                             cmd, &res->base.addrs,
                                             &res->base.iov, &res->base.iov_cnt);
-        if (ret != 0) {
+        if (ret < 0) {
             cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
             return;
         }
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 0a1a625b0e..1038c6a49f 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -352,7 +352,7 @@ static void virtio_gpu_resource_create_blob(VirtIOGPU *g,
     ret = virtio_gpu_create_mapping_iov(g, cblob.nr_entries, sizeof(cblob),
                                         cmd, &res->addrs, &res->iov,
                                         &res->iov_cnt);
-    if (ret != 0) {
+    if (ret < 0) {
         cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
         g_free(res);
         return;
@@ -931,7 +931,7 @@ virtio_gpu_resource_attach_backing(VirtIOGPU *g,
 
     ret = virtio_gpu_create_mapping_iov(g, ab.nr_entries, sizeof(ab), cmd,
                                         &res->addrs, &res->iov, &res->iov_cnt);
-    if (ret != 0) {
+    if (ret < 0) {
         cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
         return;
     }
-- 
2.34.1

Re: [v6 0/2] virtio-gpu: fix error handling and improve consistency

[Michael Tokarev]

On 1/13/26 04:52, Honglei Huang wrote:
> This series addresses error handling issues in virtio-gpu and improves
> code consistency across the virtio-gpu subsystem.
> 
> The first patch fixes a critical bug in virgl_cmd_resource_create_blob()
> where an inverted error check causes the function to fail when it should
> succeed. This is a standalone bug fix that should be backported.
> 
> The second patch improves code consistency by unifying the error checking
> style for virtio_gpu_create_mapping_iov() in if-statement contexts across
> virtio-gpu files, following the preferred QEMU coding convention.
> 
> Changes since v5:
> - Reverted changes to virtio-gpu-rutabaga.c to keep CHECK macro usage
>    consistent with other error checks in the same file
> - Updated patch 2 commit message to clarify that CHECK macro patterns
>    in rutabaga.c are intentionally left unchanged
> 
> Changes since v4:
> - Split the single patch into two separate patches for better clarity
> - Separated the critical bug fix from the style consistency improvements
> - The bug fix (patch 1) can now be easily identified and backported
> - The consistency improvements (patch 2) are clearly marked as cleanup
> 
> Changes since v3:
> - Extended consistency improvements to virtio-gpu-rutabaga.c
> - Changed CHECK(!ret) to CHECK(ret >= 0) and CHECK(!result) to
>    CHECK(result >= 0) in rutabaga functions for consistency
> - Now covers all virtio-gpu files that use virtio_gpu_create_mapping_iov()
> 
> Changes since v2:
> - Use 'if (ret < 0)' instead of 'if (ret != 0)' following maintainer's
>    feedback on preferred QEMU coding style for error checking functions
>    that return 0 on success and negative on error
> - Updated all similar usages across virtio-gpu files for consistency
> - Expanded scope from single function fix to codebase-wide style consistency
> 
> Honglei Huang (2):
>    virtio-gpu: fix error handling in virgl_cmd_resource_create_blob
>    virtio-gpu: use consistent error checking for
>      virtio_gpu_create_mapping_iov
> 
>   hw/display/virtio-gpu-virgl.c | 4 ++--
>   hw/display/virtio-gpu.c       | 4 ++--
>   2 files changed, 4 insertions(+), 4 deletions(-)
> 
Is this a qemu-stable material?  I'm a bit confused here.  The first
patch looks like it is, the second I can't decide.

Please let me know if I should pick this up for qemu-stable or not.
For now I'm picking up the first change.

Thanks,

/mjt

Re: [v6 0/2] virtio-gpu: fix error handling and improve consistency

[Markus Armbruster]

Michael Tokarev <mjt@tls.msk.ru> writes:

> On 1/13/26 04:52, Honglei Huang wrote:
>> This series addresses error handling issues in virtio-gpu and improves
>> code consistency across the virtio-gpu subsystem.
>> The first patch fixes a critical bug in virgl_cmd_resource_create_blob()
>> where an inverted error check causes the function to fail when it should
>> succeed. This is a standalone bug fix that should be backported.
>> The second patch improves code consistency by unifying the error checking
>> style for virtio_gpu_create_mapping_iov() in if-statement contexts across
>> virtio-gpu files, following the preferred QEMU coding convention.
>> Changes since v5:
>> - Reverted changes to virtio-gpu-rutabaga.c to keep CHECK macro usage
>>    consistent with other error checks in the same file
>> - Updated patch 2 commit message to clarify that CHECK macro patterns
>>    in rutabaga.c are intentionally left unchanged
>> Changes since v4:
>> - Split the single patch into two separate patches for better clarity
>> - Separated the critical bug fix from the style consistency improvements
>> - The bug fix (patch 1) can now be easily identified and backported
>> - The consistency improvements (patch 2) are clearly marked as cleanup
>> Changes since v3:
>> - Extended consistency improvements to virtio-gpu-rutabaga.c
>> - Changed CHECK(!ret) to CHECK(ret >= 0) and CHECK(!result) to
>>    CHECK(result >= 0) in rutabaga functions for consistency
>> - Now covers all virtio-gpu files that use virtio_gpu_create_mapping_iov()
>> Changes since v2:
>> - Use 'if (ret < 0)' instead of 'if (ret != 0)' following maintainer's
>>    feedback on preferred QEMU coding style for error checking functions
>>    that return 0 on success and negative on error
>> - Updated all similar usages across virtio-gpu files for consistency
>> - Expanded scope from single function fix to codebase-wide style consistency
>> Honglei Huang (2):
>>    virtio-gpu: fix error handling in virgl_cmd_resource_create_blob
>>    virtio-gpu: use consistent error checking for
>>      virtio_gpu_create_mapping_iov
>>   hw/display/virtio-gpu-virgl.c | 4 ++--
>>   hw/display/virtio-gpu.c       | 4 ++--
>>   2 files changed, 4 insertions(+), 4 deletions(-)
>> 
> Is this a qemu-stable material?  I'm a bit confused here.  The first
> patch looks like it is, the second I can't decide.
>
> Please let me know if I should pick this up for qemu-stable or not.
> For now I'm picking up the first change.

I think that's fine.

Re: [v6 0/2] virtio-gpu: fix error handling and improve consistency

[Alex Bennée]

Honglei Huang <honghuan@amd.com> writes:

> This series addresses error handling issues in virtio-gpu and improves
> code consistency across the virtio-gpu subsystem.

Looks like these patches where already pulled via another tree.

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro