On Thu, Dec 20, 2012 at 02:02:32PM +0900, Takuya Yoshikawa wrote: > On Wed, 19 Dec 2012 08:42:57 -0700 > Alex Williamson <alex.williamson@xxxxxxxxxx> wrote: > > > Please let me know if you can identify one of these as the culprit. > > They're all very simple, but there's always a chance I've missed a hard > > coding of slot numbers somewhere. Thanks, > > I identified the one: > commit b7f69c555ca430129b6cde81e9f0927531420c5c > KVM: Minor memory slot optimization > > IIUC, the problem was that you did not care about the generation of > slots which was updated by update_memslots(): > > Your patch reused the old memory slots which was there before > doing the update for invalidating the slot, and badly, we did flush > shadow pages after that before doing the second update for finally > installing the new slot. As a result, the generation did not change > from that of the invalidated one, although the ghc(gfn to hva cache) > might be stale. > > After that, kvm_write_guest_cached() checked if ghc should be > initialized by comparing ghc's generation with that old one, > resulting mark_page_dirty_in_slot() was called with the invalid > cache contents. > > Although we can do something to correct the generation alone, I do not > think such a trick is worth it because this is not a hot path. Let's > just revert the patch. Agreed. No dependencies by the following patches on it? -- 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
