[PATCH 2/2] KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32

[Marc Zyngier]

On Tue, 22 Mar 2022 05:49:29 +0000,
Oliver Upton <oupton at google.com> wrote:
> 
> On Mon, Mar 21, 2022 at 09:41:39PM -0700, Reiji Watanabe wrote:
> > On 3/18/22 12:38 PM, Oliver Upton wrote:
> > > The SMCCC does not allow the SMC64 calling convention to be used from
> > > AArch32. While KVM checks to see if the calling convention is allowed in
> > > PSCI_1_0_FN_PSCI_FEATURES, it does not actually prevent calls to
> > > unadvertised PSCI v1.0+ functions.
> > >
> > > Check to see if the requested function is allowed from the guest's
> > > execution state. Deny the call if it is not.
> > >
> > > Fixes: d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest")
> > > Cc: Will Deacon <will at kernel.org>
> > > Signed-off-by: Oliver Upton <oupton at google.com>
> > 
> > Reviewed-by: Reiji Watanabe <reijiw at google.com>
> 
> Appreciated :-)
> 
> > BTW, considering the new kvm_psci_check_allowed_function()implementation
> > in the patch-1, it might be better to call kvm_psci_check_allowed_function()
> > from kvm_psci_call() instead?  Then, we could avoid the similar issue
> > next time we support a newer PSCI version.
> 
> Good point. If Marc doesn't bite in the next day or two I'll address
> this with a new spin, otherwise I'll do a separate cleanup. Just want to
> avoid spamming on this topic since I already replied with yet another
> patch [1].

Please do, and I'll queue that for -rc1.

Thanks,

	M.

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