From patchwork Mon Mar 6 16:39:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Osipenko X-Patchwork-Id: 13161792 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0124C64EC4 for ; Mon, 6 Mar 2023 16:39:42 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9BA0F89FF7; Mon, 6 Mar 2023 16:39:41 +0000 (UTC) Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by gabe.freedesktop.org (Postfix) with ESMTPS id 327AB89FF7 for ; Mon, 6 Mar 2023 16:39:39 +0000 (UTC) Received: from workpc.. (unknown [109.252.117.89]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id C67DD6602EE4; Mon, 6 Mar 2023 16:39:36 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1678120777; bh=2qF0hUp8glqDQ1ktUcSd1pu0qhpff4ScS2Sp+BIuEaU=; h=From:To:Cc:Subject:Date:From; b=W+n6JtB8n30LcsAnOQBmt8DYkHssmRq4ybXRTK7ze63cYN5xZJVUlMFV3qx9bXVTD j/CIjJklOkgonUVbISB8pOqdQEyWUu916qZ7CzRH2fhoF61YjwPEgGXK2OXIjhFTRY MWIWty2OOEVJhkVzLYE0AAlqTGLuMApawktqS9i+kgx30nBKcAwwPXvvWTslHqSIPe jeeB88G3cA2qFqS9DNK7JjeF0WesAtmsy0Q5hJFEBoimyQ1y9wsfEGpR7kxmj9mK2D Hs1sK++8a8NiSh0iTCT8DTOhKx14TKSHD7ldpt7Bvk+DdnbmGngXx3FKYedRZ/PpV6 RY8KK9bD0cOiQ== From: Dmitry Osipenko To: Gerd Hoffmann , Rob Clark , Emil Velikov Subject: [PATCH v3] drm/virtio: Fix handling CONFIG_DRM_VIRTIO_GPU_KMS option Date: Mon, 6 Mar 2023 19:39:16 +0300 Message-Id: <20230306163916.1595961-1-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel@collabora.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Javier Martinez Canillas , Ryan Neph , David Airlie , Gurchetan Singh , virtualization@lists.linux-foundation.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" VirtIO-GPU got a new config option for disabling KMS. There were two problems left unnoticed during review when the new option was added: 1. The IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) check in the code was inverted, hence KMS was disabled when it should be enabled and vice versa. 2. The disabled KMS crashed kernel with a NULL dereference in drm_kms_helper_hotplug_event(), which shall not be invoked with a disabled KMS. Fix the inverted config option check in the code and skip handling the VIRTIO_GPU_EVENT_DISPLAY sent by host when KMS is disabled in guest to fix the crash. Acked-by: Gerd Hoffmann Fixes: 72122c69d717 ("drm/virtio: Add option to disable KMS support") Signed-off-by: Dmitry Osipenko Reviewed-by: Emil Velikov --- Changelog: v3: - Moved another similar "has_edid" occurence under the "num_scanouts" condition in virtio_gpu_init(), like was suggested by Emil Velikov. - Added ack from Gerd Hoffmann. v2: - Moved the "has_edid" under the "num_scanouts" condition, like was suggested by Gerd Hoffmann. drivers/gpu/drm/virtio/virtgpu_kms.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c index 874ad6c2621a..43e237082cec 100644 --- a/drivers/gpu/drm/virtio/virtgpu_kms.c +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c @@ -43,11 +43,13 @@ static void virtio_gpu_config_changed_work_func(struct work_struct *work) virtio_cread_le(vgdev->vdev, struct virtio_gpu_config, events_read, &events_read); if (events_read & VIRTIO_GPU_EVENT_DISPLAY) { - if (vgdev->has_edid) - virtio_gpu_cmd_get_edids(vgdev); - virtio_gpu_cmd_get_display_info(vgdev); - virtio_gpu_notify(vgdev); - drm_helper_hpd_irq_event(vgdev->ddev); + if (vgdev->num_scanouts) { + if (vgdev->has_edid) + virtio_gpu_cmd_get_edids(vgdev); + virtio_gpu_cmd_get_display_info(vgdev); + virtio_gpu_notify(vgdev); + drm_helper_hpd_irq_event(vgdev->ddev); + } events_clear |= VIRTIO_GPU_EVENT_DISPLAY; } virtio_cwrite_le(vgdev->vdev, struct virtio_gpu_config, @@ -224,7 +226,7 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev) vgdev->num_scanouts = min_t(uint32_t, num_scanouts, VIRTIO_GPU_MAX_SCANOUTS); - if (IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) || !vgdev->num_scanouts) { + if (!IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) || !vgdev->num_scanouts) { DRM_INFO("KMS disabled\n"); vgdev->num_scanouts = 0; vgdev->has_edid = false; @@ -253,9 +255,9 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev) if (num_capsets) virtio_gpu_get_capsets(vgdev, num_capsets); - if (vgdev->has_edid) - virtio_gpu_cmd_get_edids(vgdev); if (vgdev->num_scanouts) { + if (vgdev->has_edid) + virtio_gpu_cmd_get_edids(vgdev); virtio_gpu_cmd_get_display_info(vgdev); virtio_gpu_notify(vgdev); wait_event_timeout(vgdev->resp_wq, !vgdev->display_info_pending,