Akihiko Odaki <akihiko.od...@daynix.com> writes:
> On 2025/06/03 20:01, Alex Bennée wrote:
>> QOM objects can be embedded in other QOM objects and managed as part
>> of their lifetime but this isn't the case for
>> virtio_gpu_virgl_hostmem_region. However before we can split it out we
>> need some other way of associating the wider data structure with the
>> memory region.
>> Fortunately MemoryRegion has an opaque pointer. This is passed down
>> to
>> MemoryRegionOps for device type regions but is unused in the
>> memory_region_init_ram_ptr() case. Use the opaque to carry the
>> reference and allow the final MemoryRegion object to be reaped when
>> its reference count is cleared.
>> Signed-off-by: Manos Pitsidianakis <manos.pitsidiana...@linaro.org>
>> Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
>> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
>> Message-Id: <20250410122643.1747913-2-manos.pitsidiana...@linaro.org>
>> Cc: qemu-sta...@nongnu.org
>> ---
>> include/system/memory.h | 1 +
>> hw/display/virtio-gpu-virgl.c | 23 ++++++++---------------
>> 2 files changed, 9 insertions(+), 15 deletions(-)
>> diff --git a/include/system/memory.h b/include/system/memory.h
>> index fc35a0dcad..90715ff44a 100644
>> --- a/include/system/memory.h
>> +++ b/include/system/memory.h
>> @@ -784,6 +784,7 @@ struct MemoryRegion {
>> DeviceState *dev;
>> const MemoryRegionOps *ops;
>> + /* opaque data, used by backends like @ops */
>> void *opaque;
>> MemoryRegion *container;
>> int mapped_via_alias; /* Mapped via an alias, container might be NULL
>> */
>> diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
>> index 145a0b3879..71a7500de9 100644
>> --- a/hw/display/virtio-gpu-virgl.c
>> +++ b/hw/display/virtio-gpu-virgl.c
>> @@ -52,17 +52,11 @@ virgl_get_egl_display(G_GNUC_UNUSED void *cookie)
>> #if VIRGL_VERSION_MAJOR >= 1
>> struct virtio_gpu_virgl_hostmem_region {
>> - MemoryRegion mr;
>> + MemoryRegion *mr;
>> struct VirtIOGPU *g;
>> bool finish_unmapping;
>> };
>> -static struct virtio_gpu_virgl_hostmem_region *
>> -to_hostmem_region(MemoryRegion *mr)
>> -{
>> - return container_of(mr, struct virtio_gpu_virgl_hostmem_region, mr);
>> -}
>> -
>> static void virtio_gpu_virgl_resume_cmdq_bh(void *opaque)
>> {
>> VirtIOGPU *g = opaque;
>> @@ -73,14 +67,12 @@ static void virtio_gpu_virgl_resume_cmdq_bh(void *opaque)
>> static void virtio_gpu_virgl_hostmem_region_free(void *obj)
>> {
>> MemoryRegion *mr = MEMORY_REGION(obj);
>> - struct virtio_gpu_virgl_hostmem_region *vmr;
>> + struct virtio_gpu_virgl_hostmem_region *vmr = mr->opaque;
>> VirtIOGPUBase *b;
>> VirtIOGPUGL *gl;
>> - vmr = to_hostmem_region(mr);
>> - vmr->finish_unmapping = true;
>> -
>> b = VIRTIO_GPU_BASE(vmr->g);
>> + vmr->finish_unmapping = true;
>> b->renderer_blocked--;
>> /*
>> @@ -118,8 +110,8 @@ virtio_gpu_virgl_map_resource_blob(VirtIOGPU *g,
>> vmr = g_new0(struct virtio_gpu_virgl_hostmem_region, 1);
>> vmr->g = g;
>> + mr = g_new0(MemoryRegion, 1);
>
> This patch does nothing more than adding a separate allocation for
> MemoryRegion. Besides there is no corresponding g_free(). This patch
> can be simply dropped.
As the patch says the MemoryRegion is now free'd when it is
de-referenced. Do you have a test case showing it leaking?
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
