Messages in this thread | | | Subject | Re: [PATCH 3/8] arm64: cpufeature: Add CPU capability for AArch32 EL1 support | From | Suzuki K Poulose <> | Date | Fri, 17 Apr 2020 10:44:16 +0100 |
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On 04/15/2020 02:22 PM, Marc Zyngier wrote: > On Wed, 15 Apr 2020 14:15:51 +0100 > Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > >> On 04/15/2020 11:14 AM, Will Deacon wrote: >>> On Wed, Apr 15, 2020 at 11:13:54AM +0100, Suzuki K Poulose wrote: >>>> On 04/14/2020 10:31 PM, Will Deacon wrote: >>>>> Although we emit a "SANITY CHECK" warning and taint the kernel if we >>>>> detect a CPU mismatch for AArch32 support at EL1, we still online the >>>>> CPU with disastrous consequences for any running 32-bit VMs. >>>>> >>>>> Introduce a capability for AArch32 support at EL1 so that late onlining >>>>> of incompatible CPUs is forbidden. >>>>> >>>>> Signed-off-by: Will Deacon <will@kernel.org> >>>> >>>> One of the other important missing sanity check for KVM is the VMID width >>>> check. I will code something up. >>> >>> Cheers! Do we handle things like the IPA size already? >> >> Good point. No, we don't. I will include this too. > > There is also the question of the ARMv8.5-GTG extension. I have a patch > that treats it as non-strict, but that approach would fail with KVM if > we online a late CPU without support for the right page size at S2.
Good point. Again this can be added to the list of checks performed on the hot-plugged CPUs along with IPA, VMID width.
Cheers Suzuki
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