Re: [PATCH 1/3] KVM: arm64: Only read HPFAR_EL2 when value is architecturally valid

[Marc Zyngier <maz@kernel.org>]

On Wed, 02 Apr 2025 12:15:52 +0100,
Marc Zyngier <maz@kernel.org> wrote:
> 
> On Tue, 01 Apr 2025 23:42:32 +0100,
> Oliver Upton <oliver.upton@linux.dev> wrote:
> > 
> > KVM's logic for deciding when HPFAR_EL2 is UNKNOWN doesn't align with
> > the architecture. Most notably, KVM assumes HPFAR_EL2 contains the
> > faulting IPA even in the case of an SEA.
> > 
> > Align the logic with the architecture rather than attempting to
> > paraphrase it. Additionally, take the opportunity to improve the
> > language around ARM erratum #834220 such that it actually describes the
> > bug.
> > 
> > Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
> > ---
> >  arch/arm64/include/asm/esr.h           |  1 +
> >  arch/arm64/kvm/hyp/include/hyp/fault.h | 46 ++++++++++++++++----------
> >  2 files changed, 29 insertions(+), 18 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
> > index d1b1a33f9a8b..7b096ed87360 100644
> > --- a/arch/arm64/include/asm/esr.h
> > +++ b/arch/arm64/include/asm/esr.h
> > @@ -121,6 +121,7 @@
> >  #define ESR_ELx_FSC_SEA_TTW(n)	(0x14 + (n))
> >  #define ESR_ELx_FSC_SECC	(0x18)
> >  #define ESR_ELx_FSC_SECC_TTW(n)	(0x1c + (n))
> > +#define ESR_ELx_FSC_ADDRESS	(0x00)
> 
> I think this should probably read "ADDRESS_SIZE", rather than just
> "ADDRESS".

Actually, we have

#define ESR_ELx_FSC_ADDRSZ	(0x00)

since

61e30b9eef7f ("KVM: arm64: nv: Implement nested Stage-2 page table walk logic")

It just isn't at the expected spot.

	M.

-- 
Jazz isn't dead. It just smells funny.