[PATCH 5/8] KVM: arm64: Remove PMU RAZ/WI handling
Marc Zyngier
maz at kernel.org
Fri Nov 27 03:50:02 EST 2020
On 2020-11-26 15:06, Alexandru Elisei wrote:
> Hi Marc,
>
> This patch looks correct to me, I checked in the Arm ARM DDI 0487F.b
> and indeed
> all accesses to the PMU registers are UNDEFINED if the PMU is not
> present.
>
> I checked all the accessors and now all the PMU registers that KVM
> emulates will
> inject an undefined exception if the VCPU feature isn't set. There's
> one register
> that we don't emulate, PMMIR_EL1, I suppose that's because it's part of
> PMU
> ARMv8.4 and KVM advertises ARMv8.1; if the guest tries to access it, it
> will get
> an undefined exception and KVM will print a warning in
> emulate_sys_reg().
Funny that. I wrote a patch for that a long while ago, and obviously
never did anything with it [1]... Actually, the whole series was
silently
dropped. I guess I had other things to think about at the time!
Let me pick that up again.
> Reviewed-by: Alexandru Elisei <alexandru.elisei at arm.com>
Thanks!
M.
[1]
https://lore.kernel.org/kvmarm/20200216185324.32596-6-maz@kernel.org/
--
Jazz is not dead. It just smells funny...
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