From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE8CF3CDBD8 for ; Wed, 13 May 2026 22:11:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778710284; cv=pass; b=CWP53ank7XQozm4o9HVuAK+KMis4vYD8hlqQHNem3FT7FcZb9FoqEDcI7olnZ0BNpWAdK7Q7GGEETRm5+vxQY9Wby/GqprrZi+u3XVHxHAo/ncZLBDv6lZ9641V+up58hKemtgDZu31CCv7909rdfR36rrBIFQURJXrWDHglKF0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778710284; c=relaxed/simple; bh=/bqKGyIPeubYkSgZk34fsooAYDeCACSv3mGOGMDEtNY=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=NJFmtxtw3mV2337Fi5vsERhsugsavgDDzWnRMBj7/pDPnRbg3P8QwVTcaqq6U871BbTQ9OqfWU0RT3H8uwynozIxUB0wbAVwpmctuutTNvB+BnwyQcYphXyZofTJ9cyNBFR45CpoWBeP5X7ulxe9i+ZACTm3/S6BQ36QHlhbJLU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b=PhoABMFY; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b="PhoABMFY" ARC-Seal: i=1; a=rsa-sha256; t=1778710254; cv=none; d=zohomail.com; s=zohoarc; b=kFljbuvpV4epFUawsak7ZSItkFX5IsO3UR87Fh2IgaeBUxt2RVOrNp4SsGNarm1dn7U+cG38YoRdUUmQgd7QlfuF+hTuq5PA2enJ/oTmWDMgzP7VD6uHXTCS4fA7cCAp2pOlowm8UiQB3MKZ7mlgeKwKWqQ2BT/X0sn0JP3CqOU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1778710254; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=H66DJfTkzSFXK5GN5OZ2jS7pJA/U3BZtWdfWJMHG7FI=; b=RyF/UBmkk6rghU+EMzKrN8z75wv+tvR0nf7uZh33vaUo2UYk6KdpgRS4YVx3dMma2BBV/JC0rpmdKVyMj7h60wGtsL03Sy3xWBc/lSBi88RF3FBcMGJRb4XrGU/B0up41Nn9C1hEeszRbcS2j0rOBA+FoPjD5+VUmeb8MVMR4Rs= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=dmitry.osipenko@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1778710254; s=zohomail; d=collabora.com; i=dmitry.osipenko@collabora.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:From:From:To:To:Cc:Cc:References:In-Reply-To:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=H66DJfTkzSFXK5GN5OZ2jS7pJA/U3BZtWdfWJMHG7FI=; b=PhoABMFYuXpDQjW/CK40/Km2TEebbMpr2Nb9mdG8XUKibnTQRRA2y54SyqIbid+z 6jTCOHlZ41G/IgLuzcKpXpFjJVKvmVrTrseCPrv5esWDwGPkIwTJm6ExLAYdOFHfWme ahFFUN0izX/WkudQatSRGbat4TtguQ15BpiwB46s= Received: by mx.zohomail.com with SMTPS id 1778710252955760.417482599686; Wed, 13 May 2026 15:10:52 -0700 (PDT) Message-ID: <1efb8795-3345-46ae-8195-1b391159b90b@collabora.com> Date: Thu, 14 May 2026 01:10:48 +0300 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] drm/virtio: Extend blob UAPI with deferred-mapping hinting From: Dmitry Osipenko To: David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Pierre-Eric Pelloux-Prayer , Alyssa Rosenzweig Cc: Rob Clark , dri-devel@lists.freedesktop.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, kernel@collabora.com, Nagapuri Ramesh References: <20260501000043.2483678-1-dmitry.osipenko@collabora.com> Content-Language: en-US In-Reply-To: <20260501000043.2483678-1-dmitry.osipenko@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ZohoMailClient: External On 5/1/26 03:00, Dmitry Osipenko wrote: > If userspace never maps GEM object, then BO wastes hostmem space > because VirtIO-GPU driver maps VRAM BO at the BO's creating time. > > Make mappings on-demand by adding new RESOURCE_CREATE_BLOB IOCTL/UAPI > hinting flag telling that host mapping should be deferred until first > mapping is made when the flag is set by userspace. > > Signed-off-by: Dmitry Osipenko > Reviewed-by: Rob Clark > --- > > Changelog: > > v2: Rebased on recent kernel. Intel i915 native ctx landed to Mesa, lets to > proceed with merging the mapping hint as a first user of the feature. > > drivers/gpu/drm/virtio/virtgpu_drv.h | 2 ++ > drivers/gpu/drm/virtio/virtgpu_ioctl.c | 1 + > drivers/gpu/drm/virtio/virtgpu_vram.c | 30 +++++++++++++++++++++----- > include/uapi/drm/virtgpu_drm.h | 4 ++++ > 4 files changed, 32 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h > index f17660a71a3e..6f49213e23f8 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_drv.h > +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h > @@ -84,6 +84,7 @@ struct virtio_gpu_object_params { > uint32_t blob_mem; > uint32_t blob_flags; > uint64_t blob_id; > + uint32_t blob_hints; > }; > > struct virtio_gpu_object { > @@ -507,6 +508,7 @@ struct sg_table *virtio_gpu_vram_map_dma_buf(struct virtio_gpu_object *bo, > void virtio_gpu_vram_unmap_dma_buf(struct device *dev, > struct sg_table *sgt, > enum dma_data_direction dir); > +void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram); > > /* virtgpu_submit.c */ > int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, > diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > index c33c057365f8..01daa72b1310 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c > +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > @@ -489,6 +489,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev, > params->size = rc_blob->size; > params->blob = true; > params->blob_flags = rc_blob->blob_flags; > + params->blob_hints = rc_blob->blob_hints; > return 0; > } > > diff --git a/drivers/gpu/drm/virtio/virtgpu_vram.c b/drivers/gpu/drm/virtio/virtgpu_vram.c > index 084e80227433..4ae3cbc35dd3 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_vram.c > +++ b/drivers/gpu/drm/virtio/virtgpu_vram.c > @@ -3,6 +3,8 @@ > > #include > > +static DEFINE_MUTEX(map_lock); > + > static void virtio_gpu_vram_free(struct drm_gem_object *obj) > { > struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); > @@ -42,6 +44,11 @@ static int virtio_gpu_vram_mmap(struct drm_gem_object *obj, > if (!(bo->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE)) > return -EINVAL; > > + virtio_gpu_vram_map_deferred(vram); > + > + if (vram->map_state == STATE_INITIALIZING) > + virtio_gpu_notify(vgdev); > + > wait_event(vgdev->resp_wq, vram->map_state != STATE_INITIALIZING); > if (vram->map_state != STATE_OK) > return -EINVAL; > @@ -218,14 +225,27 @@ int virtio_gpu_vram_create(struct virtio_gpu_device *vgdev, > > virtio_gpu_cmd_resource_create_blob(vgdev, &vram->base, params, NULL, > 0); > - if (params->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE) { > - ret = virtio_gpu_vram_map(&vram->base); > - if (ret) { > - virtio_gpu_vram_free(obj); > - return ret; > + if (!(params->blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING)) { > + if (params->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE) { > + ret = virtio_gpu_vram_map(&vram->base); > + if (ret) { > + virtio_gpu_vram_free(obj); > + return ret; > + } > } > } > > *bo_ptr = &vram->base; > return 0; > } > + > +void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram) > +{ > + if (!(vram->base.blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE)) > + return; > + > + mutex_lock(&map_lock); > + if (!drm_mm_node_allocated(&vram->vram_node)) > + virtio_gpu_vram_map(&vram->base); > + mutex_unlock(&map_lock); > +} > diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h > index 9debb320c34b..ba09a4ee3e77 100644 > --- a/include/uapi/drm/virtgpu_drm.h > +++ b/include/uapi/drm/virtgpu_drm.h > @@ -200,6 +200,10 @@ struct drm_virtgpu_resource_create_blob { > __u32 cmd_size; > __u64 cmd; > __u64 blob_id; > + > +#define DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING 0x0001 > + __u32 blob_hints; > + __u32 pad2; > }; > > #define VIRTGPU_CONTEXT_PARAM_CAPSET_ID 0x0001 Applied patch to misc-next -- Best regards, Dmitry