diff options
| author | Berkant Koc <me@berkoc.com> | 2026-05-19 22:08:17 +0200 |
|---|---|---|
| committer | Hamza Mahfooz <hamzamahfooz@linux.microsoft.com> | 2026-05-25 07:31:36 -0400 |
| commit | 13d33b9ef67066c77c84273fac5a1d3fde3533d1 (patch) | |
| tree | 9997fb0afdbd5963654e0750e03944efe123b35d | |
| parent | a8878e19d2f5205ad1f170fc230c2cc25a3b9390 (diff) | |
drm/hyperv: validate resolution_count and fix WIN8 fallback
A SYNTHVID_RESOLUTION_RESPONSE with resolution_count > 64 walks past
the supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT] array in the
parse loop. Bound resolution_count against the array size, folded
into the existing zero-check.
When the WIN10 resolution probe fails, the caller in
hyperv_connect_vsp() left hv->screen_*_max / preferred_* unpopulated,
which sets mode_config.max_width / max_height to 0 and makes
drm_internal_framebuffer_create() reject every userspace framebuffer
with -EINVAL. The pre-WIN10 branch had the same gap for
preferred_width / preferred_height. Use a single post-probe fallback
guarded by screen_width_max == 0 so both paths converge on the WIN8
defaults.
Signed-off-by: Berkant Koc <me@berkoc.com>
Assisted-by: Claude:claude-opus-4-7 berkoc-pipeline
Fixes: 76c56a5affeb ("drm/hyperv: Add DRM driver for hyperv synthetic video device")
Cc: stable@vger.kernel.org # 5.14+
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
Link: https://patch.msgid.link/6945b22419c7d404b4954a113de2ac9c900dba93.1779542874.git.me@berkoc.com
| -rw-r--r-- | drivers/gpu/drm/hyperv/hyperv_drm_proto.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c index 051ecc526832..c3d0ff229e3d 100644 --- a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c +++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c @@ -391,8 +391,11 @@ static int hyperv_get_supported_resolution(struct hv_device *hdev) return -ETIMEDOUT; } - if (msg->resolution_resp.resolution_count == 0) { - drm_err(dev, "No supported resolutions\n"); + if (msg->resolution_resp.resolution_count == 0 || + msg->resolution_resp.resolution_count > + SYNTHVID_MAX_RESOLUTION_COUNT) { + drm_err(dev, "Invalid resolution count: %d\n", + msg->resolution_resp.resolution_count); return -ENODEV; } @@ -508,9 +511,13 @@ int hyperv_connect_vsp(struct hv_device *hdev) ret = hyperv_get_supported_resolution(hdev); if (ret) drm_err(dev, "Failed to get supported resolution from host, use default\n"); - } else { + } + + if (!hv->screen_width_max) { hv->screen_width_max = SYNTHVID_WIDTH_WIN8; hv->screen_height_max = SYNTHVID_HEIGHT_WIN8; + hv->preferred_width = SYNTHVID_WIDTH_WIN8; + hv->preferred_height = SYNTHVID_HEIGHT_WIN8; } hv->mmio_megabytes = hdev->channel->offermsg.offer.mmio_megabytes; |