From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from draig.lan ([185.126.160.19]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ada5d82d75bsm1255284766b.56.2025.06.05.04.57.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Jun 2025 04:57:54 -0700 (PDT) Received: from draig (localhost [IPv6:::1]) by draig.lan (Postfix) with ESMTP id 540E25F782; Thu, 05 Jun 2025 12:57:53 +0100 (BST) From: =?utf-8?Q?Alex_Benn=C3=A9e?= To: Akihiko Odaki Cc: qemu-devel@nongnu.org, Sriram Yagnaraman , "Michael S. Tsirkin" , Dmitry Osipenko , Paolo Bonzini , Peter Maydell , John Snow , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Pierrick Bouvier , Peter Xu , Fabiano Rosas , qemu-arm@nongnu.org, Thomas Huth , Alexandre Iooss , Gustavo Romero , Markus Armbruster , David Hildenbrand , Daniel P. =?utf-8?Q?Berrang=C3=A9?= , Laurent Vivier , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Mahmoud Mandour , Manos Pitsidianakis , qemu-stable@nongnu.org Subject: Re: [PATCH v4 09/17] hw/display: re-arrange memory region tracking In-Reply-To: <1a86b86d-145a-44fc-9f87-2804767fb109@daynix.com> (Akihiko Odaki's message of "Thu, 5 Jun 2025 17:34:03 +0900") References: <20250603110204.838117-1-alex.bennee@linaro.org> <20250603110204.838117-10-alex.bennee@linaro.org> <1a86b86d-145a-44fc-9f87-2804767fb109@daynix.com> User-Agent: mu4e 1.12.11; emacs 30.1 Date: Thu, 05 Jun 2025 12:57:53 +0100 Message-ID: <87o6v2764e.fsf@draig.linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-TUID: E75hQkKaWvbt Akihiko Odaki writes: > On 2025/06/03 20:01, Alex Benn=C3=A9e 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 >> Reviewed-by: Philippe Mathieu-Daud=C3=A9 >> Signed-off-by: Alex Benn=C3=A9e >> Message-Id: <20250410122643.1747913-2-manos.pitsidianakis@linaro.org> >> Cc: qemu-stable@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 N= ULL */ >> 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 >=3D 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 =3D opaque; >> @@ -73,14 +67,12 @@ static void virtio_gpu_virgl_resume_cmdq_bh(void *op= aque) >> static void virtio_gpu_virgl_hostmem_region_free(void *obj) >> { >> MemoryRegion *mr =3D MEMORY_REGION(obj); >> - struct virtio_gpu_virgl_hostmem_region *vmr; >> + struct virtio_gpu_virgl_hostmem_region *vmr =3D mr->opaque; >> VirtIOGPUBase *b; >> VirtIOGPUGL *gl; >> - vmr =3D to_hostmem_region(mr); >> - vmr->finish_unmapping =3D true; >> - >> b =3D VIRTIO_GPU_BASE(vmr->g); >> + vmr->finish_unmapping =3D true; >> b->renderer_blocked--; >> /* >> @@ -118,8 +110,8 @@ virtio_gpu_virgl_map_resource_blob(VirtIOGPU *g, >> vmr =3D g_new0(struct virtio_gpu_virgl_hostmem_region, 1); >> vmr->g =3D g; >> + mr =3D 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? --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro