[PATCH 06/11] KVM: arm64: nv: Acceletate EL0 counter accesses from hypervisor context

Oliver Upton oliver.upton at linux.dev
Thu Dec 5 09:07:57 PST 2024


On Thu, Dec 05, 2024 at 11:03:41AM +0000, Marc Zyngier wrote:
> On Thu, 05 Dec 2024 00:37:34 +0000,
> Oliver Upton <oliver.upton at linux.dev> wrote:
> > 
> > typo: accelerate
> 
> Huh, thanks!
> 
> > 
> > On Mon, Dec 02, 2024 at 05:21:29PM +0000, Marc Zyngier wrote:
> 
> [...]
> 
> > > +	case SYS_CNTVCT_EL0:
> > > +	case SYS_CNTVCTSS_EL0:
> > > +		/* If !ELIsInHost(EL2), the guest's CNTVOFF_EL2 applies */
> > 
> > !ELIsInHost(EL0)
> 
> No, and that's the whole point. CNTVOFF_EL2 applies at all times when
> HCR_EL2==0 and that we're at EL2. From the pseudocode for CNTVCT_EL0:

Dammit, I don't know how many times I misread "CNTPCT" here rather than
CNTVCT. Sorry for the noise.

-- 
Thanks,
Oliver



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