On Thu, Jul 18, 2013 at 02:01:47PM +0800, Xiao Guangrong wrote: > On 07/18/2013 01:31 PM, Gleb Natapov wrote: > > On Thu, Jul 18, 2013 at 12:52:37PM +0800, Xiao Guangrong wrote: > >> Currently, fast page fault tries to fix mmio page fault when the > >> generation number is invalid (spte.gen != kvm.gen) and returns to > >> guest to retry the fault since it sees the last spte is nonpresent > >> which causes infinity loop > >> > >> It can be triggered only on AMD host since the mmio page fault is > >> recognized as ept-misconfig > >> > > We still call into regular page fault handler from ept-misconfig > > handler, but fake zero error_code we provide makes page_fault_can_be_fast() > > return false. > > Yes. > > > > > Shouldn't shadow paging trigger this too? I haven't encountered this on > > Intel without ept. > > Since currently fast page fault only works for direct mmu. :) Ah, yes. So with shadow page and paging disabled in a guest is can happen eventually, but we do not trigger it for some reason? -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
