On Mon, Aug 5, 2024 at 4:02 PM Oliver Upton <oliver.upton@xxxxxxxxx> wrote: > > On Fri, Aug 02, 2024 at 10:40:31PM +0000, Anish Moorthy wrote: > > Right now userspace just gets a bare EFAULT when the stage-2 fault > > handler fails to fault in the relevant page. Set up a memory fault exit > > when this happens, which at the very least eases debugging and might > > also let userspace decide on/take some specific action other than > > crashing the VM. > > There are several other 'bare' EFAULTs remaining (unexpected fault > context, failed vma_lookup(), nested PTW), so the patch doesn't exactly > match the shortlog. > > Is there a reason why those are unaddressed? In any case, it doesn't > hurt to be unambiguous in the shortlog if we're only focused on this single > error condition, e.g. > > KVM: arm64: Do a memory fault exit if __gfn_to_pfn_memslot() fails Ah, right- forgot to address this before I sent it out. Basically: those cases you mention (besides MTE, where it seems simple enough to add an annotation) happen before vma_pagesize is calculated, and it doesn't look trivial to just move logic around to do that calculation up at the top. Lmk if there's a good solution here, but in the meantime I'll just take your suggested shortlog [1] https://github.com/torvalds/linux/blob/master/arch/arm64/kvm/mmu.c#L1479-L1514
