Il 20/06/2013 18:34, Takuya Yoshikawa ha scritto: > From: Takuya Yoshikawa <[email protected]> > > Without this information, users will just see unexpected performance > problems and there is little chance we will get good reports from them: > note that mmio generation is increased even when we just start, or stop, > dirty logging for some memory slot, in which case users cannot expect > all shadow pages to be zapped. > > printk_ratelimited() is used for this taking into account the problems > that we can see the information many times when we start multiple VMs > and guests can trigger this by reading ROM in a loop for example. > > Signed-off-by: Takuya Yoshikawa <[email protected]> > --- > Interestingly, I saw this information printed twice every time. > Looks like current_mmio_gen can become mmio_max_gen... > arch/x86/kvm/mmu.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index c60c5da..54e3968 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -4385,8 +4385,10 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm) > * The max value is MMIO_MAX_GEN - 1 since it is not called > * when mark memslot invalid. > */ > - if (unlikely(kvm_current_mmio_generation(kvm) >= (MMIO_MAX_GEN - 1))) > + if (unlikely(kvm_current_mmio_generation(kvm) >= (MMIO_MAX_GEN - 1))) {
There is an off-by-one here (that I can fix in a separate patch). The right test is >= MMIO_MAX_GEN, since we have: #define MMIO_MAX_GEN ((1 << MMIO_GEN_SHIFT) - 1) Paolo > + printk_ratelimited(KERN_INFO "kvm: zapping shadow pages for > mmio generation wraparound\n"); > kvm_mmu_invalidate_zap_all_pages(kvm); > + } > } > > static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
