Re: [PATCH v2] arm64: KVM: Use SMCCC_ARCH_WORKAROUND_1 for Falkor BP hardening

From: Will Deacon
Date: Tue Mar 20 2018 - 05:47:44 EST


On Mon, Mar 19, 2018 at 06:30:16PM +0000, Marc Zyngier wrote:
> On 06/03/18 10:32, Marc Zyngier wrote:
> > On Mon, 05 Mar 2018 17:06:43 +0000,
> > Shanker Donthineni wrote:
> >>
> >> The function SMCCC_ARCH_WORKAROUND_1 was introduced as part of SMC
> >> V1.1 Calling Convention to mitigate CVE-2017-5715. This patch uses
> >> the standard call SMCCC_ARCH_WORKAROUND_1 for Falkor chips instead
> >> of Silicon provider service ID 0xC2001700.
> >>
> >> Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
> >> ---
> >> Chnages since v1:
> >> - Trivial change in cpucaps.h (refresh after removing ARM64_HARDEN_BP_POST_GUEST_EXIT)
> >>
> >> arch/arm64/include/asm/cpucaps.h | 5 ++--
> >> arch/arm64/include/asm/kvm_asm.h | 2 --
> >> arch/arm64/kernel/bpi.S | 8 ------
> >> arch/arm64/kernel/cpu_errata.c | 55 ++++++++++++++--------------------------
> >> arch/arm64/kvm/hyp/entry.S | 12 ---------
> >> arch/arm64/kvm/hyp/switch.c | 10 --------
> >> 6 files changed, 21 insertions(+), 71 deletions(-)
> >
> > Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> >
> > Will/Catalin, if you want to take it via the arm64 tree, that's fine
> > by me.
>
> Please allow me to change my mind. This is going to conflict horribly
> with the VHE rework and the HYP randomization patches.
>
> I'll take it via the KVM tree, which will make everyone's life a lot easier.

Sure; if you need it:

Acked-by: Will Deacon <will.deacon@xxxxxxx>

You'll probably want to comment out the ARM64_HARDEN_BP_POST_GUEST_EXIT
capability for now to avoid silly conflicts in -next. I can remove and
renumber at -rc1.

Will