On 12/7/18 12:39 PM, Kristina Martsenko wrote: > From: Mark Rutland <mark.rutland@xxxxxxx> > > In subsequent patches we're going to expose ptrauth to the host kernel > and userspace, but things are a bit trickier for guest kernels. For the > time being, let's hide ptrauth from KVM guests. > > Regardless of how well-behaved the guest kernel is, guest userspace > could attempt to use ptrauth instructions, triggering a trap to EL2, > resulting in noise from kvm_handle_unknown_ec(). So let's write up a > handler for the PAC trap, which silently injects an UNDEF into the > guest, as if the feature were really missing. Reviewing the long thread that accompanied v5, I thought we were *not* going to trap PAuth instructions from the guest. In particular, the OS distribution may legitimately be built to include hint-space nops. This includes XPACLRI, which is used by the C++ exception unwinder and not controlled by SCTLR_EL1.EnI{A,B}. It seems like the header comment here, and > +/* > + * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into > + * a NOP). > + */ > +static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu, struct kvm_run *run) > + here, need updating. r~ _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm