drm/vmwgfx: Don't use screen objects when SEV is active

stable inclusion
from stable-v5.10.159
commit 007f561f599f4977e1e281a92db8c11ad78762d4
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7NTXH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=007f561f599f4977e1e281a92db8c11ad78762d4



--------------------------------

commit 6e902936 upstream.

When SEV is enabled gmr's and mob's are explicitly disabled because
the encrypted system memory can not be used by the hypervisor.

The driver was disabling GMR's but the presentation code, which depends
on GMR's, wasn't honoring it which lead to black screen on hosts
with SEV enabled.

Make sure screen objects presentation is not used when guest memory
regions have been disabled to fix presentation on SEV enabled hosts.

Fixes: 3b0d6458 ("drm/vmwgfx: Refuse DMA operation when SEV encryption is active")
Cc: <stable@vger.kernel.org> # v5.7+
Signed-off-by: Zack Rusin <zackr@vmware.com>
Reported-by: Nicholas Hunt <nhunt@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221201175341.491884-1-zack@kde.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>