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 0D5AB17BB25 for ; Mon, 2 Dec 2024 16:19:48 +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=1733156390; cv=pass; b=kh2t2O0a/R1zsnotaiMJn5WngTZLm5/VJCKeOdpiM89pAcffOQGVs2fF65QwICVRaID5s/Xa02SikN9QQy3TOAfdogzB666ZMfWifx4PS1xH9DBYhoQODjlsaY1ftaR19O6Gne7d61aZVBckUD7jfkDkgZBeIfBpRGJot1Efw+I= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733156390; c=relaxed/simple; bh=9886ePHFbFwZswns+3r4oLgWrrfQmqFqiN9QAho9evs=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=bNB2ru4SlBi7Cv3/1Pzq5o4+l5zpGyeMMEvP5KUVapJ0rRCzMbli6Ru+myiPBNw1WctGxjWF+9Hn0j78Z+dk5Vf5nTumSZJ1WONodOFXMk04ZyNAknSWi42GJh7hl+r4v3kUFB86MLFN9eIrgpk4hEbcHrIDf+HTRgCVrrJJ3BY= 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=bAr+Jd6G; 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="bAr+Jd6G" ARC-Seal: i=1; a=rsa-sha256; t=1733156379; cv=none; d=zohomail.com; s=zohoarc; b=LsoCdLeq6EYAL0wGIbReDDAK55iGJwXrJzzxm7ZidOpcezLJGFZKfL/d3TG8G+SVynIdLf7lRfmhGgZ+RADg/coOpMbX/XDX0Qk02MYMxn7G31NTJLLaInn0GNPNS12nSd1X8dr+kz2P2NGBYpb8RCmJUTiE3VLalCLb/isD3Q4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1733156379; 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=hvTFZp9I5yxeN/zmCcaf6GmfmPRKl/MYvUNTRFeSrLM=; b=WSfN/Rh7++k8NNm2ncrESO7z2L2wgmCOZH17152ecS5cnOOGdqDKsaGfKmx3Zz0jfuDTx34gRhAe883d2n7DuQd4QuTc36oqDxQXjaXjpCTMBEetaxZM4CUf8jr8cvnIX9FCfRGiOQvxMxlI1hTxcgacOGixp29lIl5RcfZax6c= 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=1733156379; 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=hvTFZp9I5yxeN/zmCcaf6GmfmPRKl/MYvUNTRFeSrLM=; b=bAr+Jd6GAH1T2eEsUIUiuZTUdIGB3mM0D3njEbgVJhEs/3IQEe+erVDdEQBXnjnw zwzNeMoSAykhD8B1NlkNeAzdWEkI/b/PYHqyMn8OUaQvr5Vrp6bfIxjhKLUxcdKd+9H glhk6HKRKKDvviq4/e6viyL4QrvPbjFpgmRqONj8= Received: by mx.zohomail.com with SMTPS id 1733156377347547.5350538930811; Mon, 2 Dec 2024 08:19:37 -0800 (PST) Message-ID: <3ca0382c-a410-4424-a5a4-7c1b8be7ebed@collabora.com> Date: Mon, 2 Dec 2024 19:19:31 +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 v5] drm/virtio: Add drm_panic support From: Dmitry Osipenko To: Ryosuke Yasuoka , airlied@redhat.com, kraxel@redhat.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, daniel@ffwll.ch, jfalempe@redhat.com, christophe.jaillet@wanadoo.fr Cc: virtualization@lists.linux.dev, spice-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org References: <20241129122408.4167150-1-ryasuoka@redhat.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ZohoMailClient: External On 12/2/24 17:29, Dmitry Osipenko wrote: > On 11/29/24 15:24, Ryosuke Yasuoka wrote: > .... >> +static int virtio_drm_get_scanout_buffer(struct drm_plane *plane, >> + struct drm_scanout_buffer *sb) >> +{ >> + struct virtio_gpu_object *bo; >> + >> + if (!plane->state || !plane->state->fb || !plane->state->visible) >> + return -ENODEV; >> + >> + bo = gem_to_virtio_gpu_obj(plane->state->fb->obj[0]); >> + if (virtio_gpu_is_vram(bo)) >> + return -ENODEV; > > VirtIO-GPU now supports importing external dmabufs, we should reject > bo->base.base.import_attach here now too. > >> + >> + /* try to vmap it if possible */ >> + if (!bo->base.vaddr) { >> + int ret; >> + >> + ret = drm_gem_shmem_vmap(&bo->base, &sb->map[0]); >> + if (ret) >> + return ret; > > I've now noticed that drm_gem_shmem_vmap() expects BO reservation lock > to be held and we can't take lock it at a panic time. > > https://elixir.bootlin.com/linux/v6.12.1/source/drivers/gpu/drm/drm_gem_shmem_helper.c#L330 > > This resv warning isn't triggered because bo->base.vaddr is set for VT > framebufffer BO when panic happens. > > We actually should reject all BOs that don't have bo->base.vaddr set at > the panic time. Please correct it in v6 and rebase on top of a recent > drm-next tree. Think ideally we need to have a pre-allocated and pre-mapped BO. Then when panic happens, use that BO and tell host to display it, i.e. not to reuse currently displayed BO. This will make panic display work in all conditions. WDYT? -- Best regards, Dmitry