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virt: vmgenid: remap memory as decrypted - #30
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It was found that AWS SEV-SNP enabled instances are not able to boot with commit 81256a5 ("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 7dfede7 ("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: 81256a5 ("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> (cherry picked from commit 1b48c13)
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It was found that AWS SEV-SNP enabled instances are not able to boot with commit 81256a5 ("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 7dfede7 ("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: 81256a5 ("x86/mm: Make memremap(MEMREMAP_WB) map memory as encrypted by default")
Cc: stable@vger.kernel.org # 6.15+