On Wed, 20 Sep 2023 20:27:28 +0100, Suraj Jitindar Singh <surajjs@xxxxxxxxxx> wrote: > > From: Quentin Perret <qperret@xxxxxxxxxx> > > 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@xxxxxxxxxx> > Tested-by: Vincent Donnefort <vdonnefort@xxxxxxxxxx> > Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx> > Signed-off-by: Will Deacon <will@xxxxxxxxxx> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> > Link: https://lore.kernel.org/r/20221110190259.26861-8-will@xxxxxxxxxx > [ bp: clean ] What is this? > Signed-off-by: Suraj Jitindar Singh <surajjs@xxxxxxxxxx> 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. -- Without deviation from the norm, progress is not possible.
