Apparently no TLB flush is needed when there's no valid rmap in memory slot.
Signed-off-by: Kai Huang <[email protected]> --- arch/x86/kvm/mmu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index f83fc6c..d43bf50 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4309,6 +4309,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) struct kvm_memory_slot *memslot; gfn_t last_gfn; int i; + bool flush = false; memslot = id_to_memslot(kvm->memslots, slot); last_gfn = memslot->base_gfn + memslot->npages - 1; @@ -4325,7 +4326,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) for (index = 0; index <= last_index; ++index, ++rmapp) { if (*rmapp) - __rmap_write_protect(kvm, rmapp, false); + flush |= __rmap_write_protect(kvm, rmapp, + false); if (need_resched() || spin_needbreak(&kvm->mmu_lock)) cond_resched_lock(&kvm->mmu_lock); @@ -4352,7 +4354,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) * instead of PT_WRITABLE_MASK, that means it does not depend * on PT_WRITABLE_MASK anymore. */ - kvm_flush_remote_tlbs(kvm); + if (flush) + kvm_flush_remote_tlbs(kvm); } #define BATCH_ZAP_PAGES 10 -- 2.1.0 -- 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
