On Fri, Jan 05, 2018 at 02:28:59PM -0600, Shanker Donthineni wrote: > Falkor is susceptible to branch predictor aliasing and can > theoretically be attacked by malicious code. This patch > implements a mitigation for these attacks, preventing any > malicious entries from affecting other victim contexts. Thanks, Shanker. I'll pick this up (fixing the typo pointed out by Drew). One comment below. > Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> > --- > This patch has been verified using tip of > https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=kpti > and > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64?h=v4.15-rc6&id=c622cc013cece073722592cff1ac6643a33b1622 > > arch/arm64/include/asm/cpucaps.h | 3 ++- > arch/arm64/include/asm/kvm_asm.h | 2 ++ > arch/arm64/kernel/bpi.S | 8 +++++++ > arch/arm64/kernel/cpu_errata.c | 49 ++++++++++++++++++++++++++++++++++++++-- > arch/arm64/kvm/hyp/entry.S | 12 ++++++++++ > arch/arm64/kvm/hyp/switch.c | 10 ++++++++ > 6 files changed, 81 insertions(+), 3 deletions(-) [...] > diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S > index 12ee62d..9c45c6a 100644 > --- a/arch/arm64/kvm/hyp/entry.S > +++ b/arch/arm64/kvm/hyp/entry.S > @@ -196,3 +196,15 @@ alternative_endif > > eret > ENDPROC(__fpsimd_guest_restore) > + > +ENTRY(__qcom_hyp_sanitize_btac_predictors) > + /** > + * Call SMC64 with Silicon provider serviceID 23<<8 (0xc2001700) > + * 0xC2000000-0xC200FFFF: assigned to SiP Service Calls > + * b15-b0: contains SiP functionID > + */ > + movz x0, #0x1700 > + movk x0, #0xc200, lsl #16 > + smc #0 > + ret As I mentioned to Jayachandran for the Cavium patches [1], using an unallocated SMC number like this may cause a problem for some platforms, such as qemu. Using the PSCI GET_VERSION call avoids this issue, so I'm relying on you to handle any breakage reports that arise from this change then. FWIW: we're currently looking into extending PSCI/SMCCC so that a standardised mechanism can be implemented without the overhead of the current register stacking requirements. Cheers, Will [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-January/552511.html _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
