Re: [PATCH v5 3/7] arm64/kvm: disable access to AMU registers from kvm guests

Ionela Voinescu
2020-03-02T14:32:48Z

Hi Marc,

On Thursday 27 Feb 2020 at 19:58:32 (+0000), Marc Zyngier wrote:
[..]
> > static bool trap_ptrauth(struct kvm_vcpu *vcpu,
> > struct sys_reg_params *p,
> > const struct sys_reg_desc *rd)
> > @@ -1078,8 +1092,10 @@ static u64 read_id_reg(const struct kvm_vcpu
> > *vcpu,
> > (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
> > u64 val = raz ? 0 : read_sanitised_ftr_reg(id);
> >
> > - if (id == SYS_ID_AA64PFR0_EL1 && !vcpu_has_sve(vcpu)) {
> > - val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
> > + if (id == SYS_ID_AA64PFR0_EL1) {
> > + if (!vcpu_has_sve(vcpu))
> > + val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
> > + val &= ~(0xfUL << ID_AA64PFR0_AMU_SHIFT);
>
> This will definitely conflict with some of the ongoing rework I have[1].
> I'm happy to provide this as a stable branch for you to rebase on top,
> or use an arm64 provided branch to rebase my stoff on top.
>
> Just let me know how you want to proceed.
>

Sure, a stable branch with this would be great. I'll wait for a reply
from Catalin for [1/7] and I'll rebase on top of your provided branch
when it's clear whether other changes are needed to this set.

Much appreciated,
Ionela.

> Thanks,
>
> M.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=kvm-arm64/debug-fixes-5.6&id=454fb7398d3626328f7f771c07d21e894e4e1a3b
> --
> Jazz is not dead. It just smells funny...