virt: vmgenid: remap memory as decrypted
It was found that AWS SEV-SNP enabled instances are not able to boot with
commit 81256a50aa0f ("x86/mm: Make memremap(MEMREMAP_WB) map memory as
encrypted by default") applied and the reason seems to be the vmgenid
device which requires unencrypted writeable memory.
A similar problem was previously fixed in DRM with commit
7dfede7d7edd ("drm/vmwgfx: Fix guests running with TDX/SEV").
Note, trusting vmgenid device in a Confidential VM is questionable: the
malicious host may intentionally avoid notifying the guest when a copy is
created.
Fixes: 81256a50aa0f ("x86/mm: Make memremap(MEMREMAP_WB) map memory as encrypted by default")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org # 6.15+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
1 file changed
