From patchwork Mon Mar 6 14:32:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Osipenko X-Patchwork-Id: 13161300 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 EC98EC61DA4 for ; Mon, 6 Mar 2023 14:33:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3508510E255; Mon, 6 Mar 2023 14:33:09 +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 5A32510E255 for ; Mon, 6 Mar 2023 14:33:07 +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 2A553660220B; Mon, 6 Mar 2023 14:33:05 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1678113186; bh=gJrshKNUaitWNWbqYmQJvTDpbgAcQ7xq5COOHL06j48=; h=From:To:Cc:Subject:Date:From; b=VGYL25Nk+XguA0di2RClfj+YaJ7Z/yUfecAaaKgHQlu2cWiveT+N/ZkiXqQZ7ZBfv 66hnylM0mBMgus89gmzTNnWbJ5fzRbSOwmj3OvyO+r0TaunD8uhDqxKjtiKU8aSCfL 84WVBND/GmoitV0965ylpRG9ZH5dUyvGdMHljXxFK0eFR6FeKjlR8VrZm9R5KcWZD5 rwv5qfVlh7YdYgOVpo7N9mKKcxS18BDm4NUikrXb0kcpjV0XCmu9hNesHp+si7H06b xdi+mkCoOcffTEpKjTRORXPfUkLg5RgpVmdShpmTICo5TdD2fa/lvWmSEjPneOFf9t bnDfiWFXi1A1A== From: Dmitry Osipenko To: Gerd Hoffmann , Rob Clark Subject: [PATCH v2] drm/virtio: Fix handling CONFIG_DRM_VIRTIO_GPU_KMS option Date: Mon, 6 Mar 2023 17:32:34 +0300 Message-Id: <20230306143234.1561759-1-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. Fixes: 72122c69d717 ("drm/virtio: Add option to disable KMS support") Signed-off-by: Dmitry Osipenko Acked-by: Gerd Hoffmann --- Changelog: v2: - Moved the "has_edid" under the "num_scanouts" condition, like was suggested by Gerd Hoffmann. drivers/gpu/drm/virtio/virtgpu_kms.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c index 874ad6c2621a..15f2519988e7 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;