On Wed, 20 Sep 2023 20:27:28 +0100, Suraj Jitindar Singh surajjs@amazon.com wrote:
From: Quentin Perret qperret@google.com
commit 43c1ff8b75011bc3e3e923adf31ba815864a2494 upstream.
Memory regions marked as "no-map" in the host device-tree routinely include TrustZone carev-outs and DMA pools. Although donating such pages to the hypervisor may not breach confidentiality, it could be used to corrupt its state in uncontrollable ways. To prevent this, let's block host-initiated memory transitions targeting "no-map" pages altogether in nVHE protected mode as there should be no valid reason to do this in current operation.
Thankfully, the pKVM EL2 hypervisor has a full copy of the host's list of memblock regions, so we can easily check for the presence of the MEMBLOCK_NOMAP flag on a region containing pages being donated from the host.
Reviewed-by: Philippe Mathieu-Daudé philmd@linaro.org Tested-by: Vincent Donnefort vdonnefort@google.com Signed-off-by: Quentin Perret qperret@google.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20221110190259.26861-8-will@kernel.org [ bp: clean ]
What is this?
Signed-off-by: Suraj Jitindar Singh surajjs@amazon.com
What is the rationale for backporting this? It wasn't tagged as Cc: to stable for a reason: pKVM isn't functional upstream, and won't be for the next couple of cycles *at least*.
So at it stands, I'm against such a backport.
Thanks,
M.