On Tue, Sep 15, 2020 at 11:42:16AM +0100, Marc Zyngier wrote: > I recently managed to trigger an interesting failure mode, where a > guest would be stuck on an instruction abort due to a permission > fault. Interestingly enough, this IABT had S1PTW set in the ESR, > indicating that it was trying to *write* to the PT. We fix it by > adding the execute permission (it's an IABT, after all...), and going > nowhere fast. > > Note that it can only happen on a system that can perform automatic > updates of the page table flags. > > This small series fixes the issue by revamping the S1PTW handling in > the context of execution faults. The first patch fixes the bug, and is > definitely a stable candidate. The second patch is merely a cleanup, > which can wait. > > Tested on an A55-based board. > > * From v1: > - Rename kvm_vcpu_dabt_iss1tw() to kvm_vcpu_abt_iss1tw() > - Don't overload kvm_vcpu_trap_is_iabt() > - Introduce kvm_vcpu_trap_is_exec_fault() For both patches: Reviewed-by: Will Deacon <will@xxxxxxxxxx> Cheers, Will
