Messages in this thread | | | Date | Mon, 23 Nov 2020 12:16:11 +0000 | From | "Dr. David Alan Gilbert" <> | Subject | Re: [PATCH v5 0/2] MTE support for KVM guest |
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* Peter Maydell (peter.maydell@linaro.org) wrote: > On Thu, 19 Nov 2020 at 15:39, Steven Price <steven.price@arm.com> wrote: > > This series adds support for Arm's Memory Tagging Extension (MTE) to > > KVM, allowing KVM guests to make use of it. This builds on the existing > > user space support already in v5.10-rc1, see [1] for an overview. > > > The change to require the VMM to map all guest memory PROT_MTE is > > significant as it means that the VMM has to deal with the MTE tags even > > if it doesn't care about them (e.g. for virtual devices or if the VMM > > doesn't support migration). Also unfortunately because the VMM can > > change the memory layout at any time the check for PROT_MTE/VM_MTE has > > to be done very late (at the point of faulting pages into stage 2). > > I'm a bit dubious about requring the VMM to map the guest memory > PROT_MTE unless somebody's done at least a sketch of the design > for how this would work on the QEMU side. Currently QEMU just > assumes the guest memory is guest memory and it can access it > without special precautions...
Although that is also changing because of the encrypted/protected memory in things like SEV.
Dave
> thanks > -- PMM > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
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