Messages in this thread | | | Date | Tue, 28 Feb 2023 13:47:18 +0100 | Subject | Re: [PATCH v3] drm/virtio: Add option to disable KMS support | From | Thomas Zimmermann <> |
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Am 28.02.23 um 13:34 schrieb Thomas Zimmermann: > Hi > > Am 27.02.23 um 19:15 schrieb Rob Clark: >> On Mon, Feb 27, 2023 at 9:57 AM Dmitry Osipenko >> <dmitry.osipenko@collabora.com> wrote: >>> >>> On 2/27/23 20:38, Rob Clark wrote: >>> ... >>>> + if (IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS)) { >>>> + /* get display info */ >>>> + virtio_cread_le(vgdev->vdev, struct virtio_gpu_config, >>>> + num_scanouts, &num_scanouts); >>>> + vgdev->num_scanouts = min_t(uint32_t, num_scanouts, >>>> + VIRTIO_GPU_MAX_SCANOUTS); >>>> + if (!vgdev->num_scanouts) { >>>> + /* >>>> + * Having an EDID but no scanouts is >>>> non-sensical, >>>> + * but it is permitted to have no scanouts and no >>>> + * EDID (in which case DRIVER_MODESET and >>>> + * DRIVER_ATOMIC are not advertised) >>>> + */ >>>> + if (vgdev->has_edid) { >>>> + DRM_ERROR("num_scanouts is zero\n"); >>>> + ret = -EINVAL; >>>> + goto err_scanouts; >>>> + } >>>> + dev->driver_features &= ~(DRIVER_MODESET | >>>> DRIVER_ATOMIC); >>> >>> If it's now configurable by host, why do we need the >>> CONFIG_DRM_VIRTIO_GPU_KMS? >> >> Because a kernel config option makes it more obvious that >> modeset/atomic ioctls are blocked. Which makes it more obvious about >> where any potential security issues apply and where fixes need to get >> backported to. The config option is the only thing _I_ want, >> everything else is just a bonus to help other people's use-cases. > > I find this very vague. What's the security thread? > > And if the config option is useful, shouldn't it be DRM-wide? The > modesetting ioctl calls are shared among all drivers.
For reference, here's an older discussion about render-only devices.
https://lore.kernel.org/dri-devel/20221011110437.15258-1-christian.koenig@amd.com/
> > Best regards > Thomas > >> >> BR, >> -R >
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev [unhandled content-type:application/pgp-signature]
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