Re: [PATCH 1/3] KVM: arm64: vgic: Add Apple M2 cpus to the list of broken SEIS implementations

Marc Zyngier
2023-01-03T18:10:00Z

Hi Nathan,

On Tue, 03 Jan 2023 17:59:12 +0000,
Nathan Chancellor <nathan@kernel.org> wrote:
>
> Hi Marc,
>
> I have only been lurking on the kvmarm mailing list for a little bit and
> it has mainly just been reading patches/review to get more familiar with
> various virtualization concepts so I apologize if the following review
> is rather shallow but...

No need to apologise. Any extra pair of eye is welcome, specially when
the idiot behind the keyboard writes stuff like the patch below...

>
> On Tue, Jan 03, 2023 at 09:50:20AM +0000, Marc Zyngier wrote:
> > I really hoped that Apple had fixed their not-quite-a-vgic implementation
> > when moving from M1 to M2. Alas, it seems they didn't, and running
> > a buggy EFI version results in the vgic generating SErrors outside
> > of the guest and taking the host down.
> >
> > Apply the same workaround as for M1. Yes, this is all a bit crap.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> > arch/arm64/include/asm/cputype.h | 4 ++++
> > arch/arm64/kvm/vgic/vgic-v3.c | 3 ++-
> > 2 files changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
> > index 4e8b66c74ea2..683ca3af4084 100644
> > --- a/arch/arm64/include/asm/cputype.h
> > +++ b/arch/arm64/include/asm/cputype.h
> > @@ -124,6 +124,8 @@
> > #define APPLE_CPU_PART_M1_FIRESTORM_PRO 0x025
> > #define APPLE_CPU_PART_M1_ICESTORM_MAX 0x028
> > #define APPLE_CPU_PART_M1_FIRESTORM_MAX 0x029
> > +#define APPLE_CPU_PART_M2_BLIZZARD 0x032
> > +#define APPLE_CPU_PART_M2_AVALANCHE 0x033
> >
> > #define AMPERE_CPU_PART_AMPERE1 0xAC3
> >
> > @@ -177,6 +179,8 @@
> > #define MIDR_APPLE_M1_FIRESTORM_PRO MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M1_FIRESTORM_PRO)
> > #define MIDR_APPLE_M1_ICESTORM_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M1_ICESTORM_MAX)
> > #define MIDR_APPLE_M1_FIRESTORM_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M1_FIRESTORM_MAX)
> > +#define MIDR_APPLE_M2_BLIZZARD MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_BLIZZARD)
> > +#define MIDR_APPLE_M2_AVALANCHE MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_AVALANCHE)
> > #define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1)
> >
> > /* Fujitsu Erratum 010001 affects A64FX 1.0 and 1.1, (v0r0 and v1r0) */
> > diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
> > index 826ff6f2a4e7..c6442b08fe80 100644
> > --- a/arch/arm64/kvm/vgic/vgic-v3.c
> > +++ b/arch/arm64/kvm/vgic/vgic-v3.c
> > @@ -615,7 +615,8 @@ static const struct midr_range broken_seis[] = {
> > MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_PRO),
> > MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM_PRO),
> > MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_MAX),
> > - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM_MAX),
>
> The commit message makes no note of this removal, was it intentional?
> MIDR_APPLE_M1_FIRESTORM_MAX is only used here so I assume it is not.

Absolutely not intentional :-/ Thanks a lot for spotting this!

I'll fix this immediately (good thing I didn't send the fixes PR!).

Thanks again,

M.

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