Re: [PATCH v4 1/2] KVM: arm64: Move CMOs from user_mem_abort to the fault handlers

Marc Zyngier
2021-04-09T09:00:39Z

On Fri, 09 Apr 2021 09:08:11 +0100,
Quentin Perret <qperret@google.com> wrote:
>
> Hi Yanan,
>
> On Friday 09 Apr 2021 at 11:36:51 (+0800), Yanan Wang wrote:
> > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> > +static void stage2_invalidate_icache(void *addr, u64 size)
> > +{
> > + if (icache_is_aliasing()) {
> > + /* Flush any kind of VIPT icache */
> > + __flush_icache_all();
> > + } else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) {
> > + /* PIPT or VPIPT at EL2 */
> > + invalidate_icache_range((unsigned long)addr,
> > + (unsigned long)addr + size);
> > + }
> > +}
> > +
>
> I would recommend to try and rebase this patch on kvmarm/next because
> we've made a few changes in pgtable.c recently. It is now linked into
> the EL2 NVHE code which means there are constraints on what can be used
> from there -- you'll need a bit of extra work to make some of these
> functions available to EL2.

That's an interesting point.

I wonder whether we are missing something on the i-side for VPITP +
host stage-2 due to switching HCR_EL2.VM. We haven't changed the VMID
(still 0), but I can't bring myself to be sure it doesn't affect the
icache in this case...

M.

--
Without deviation from the norm, progress is not possible.