Commit 6b73a960 authored by Marcelo Tosatti's avatar Marcelo Tosatti
Browse files

Revert "KVM: MMU: lazily drop large spte" 

This reverts commit caf6900f.

It is causing migration failures, reference
https://bugzilla.kernel.org/show_bug.cgi?id=54061

.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent ed55705d

arch/x86/kvm/mmu.c

+16 −7
Original line number Diff line number Diff line
@@ -1105,7 +1105,8 @@ static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) 


/*

 * Write-protect on the specified @sptep, @pt_protect indicates whether

 * spte write-protection is caused by protecting shadow page table.

 * spte writ-protection is caused by protecting shadow page table.

 * @flush indicates whether tlb need be flushed.

 *

 * Note: write protection is difference between drity logging and spte

 * protection:
@@ -1114,9 +1115,10 @@ static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) 
 * - for spte protection, the spte can be writable only after unsync-ing

 *   shadow page.

 *

 * Return true if tlb need be flushed.

 * Return true if the spte is dropped.

 */

static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool pt_protect)

static bool

spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect)

{

	u64 spte = *sptep;
@@ -1126,11 +1128,17 @@ static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool pt_protect) 


	rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);



	if (__drop_large_spte(kvm, sptep)) {

		*flush |= true;

		return true;

	}



	if (pt_protect)

		spte &= ~SPTE_MMU_WRITEABLE;

	spte = spte & ~PT_WRITABLE_MASK;



	return mmu_spte_update(sptep, spte);

	*flush |= mmu_spte_update(sptep, spte);

	return false;

}



static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
@@ -1142,8 +1150,11 @@ static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, 


	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {

		BUG_ON(!(*sptep & PT_PRESENT_MASK));

		if (spte_write_protect(kvm, sptep, &flush, pt_protect)) {

			sptep = rmap_get_first(*rmapp, &iter);

			continue;

		}



		flush |= spte_write_protect(kvm, sptep, pt_protect);

		sptep = rmap_get_next(&iter);

	}
@@ -2581,8 +2592,6 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, 
			break;

		}



		drop_large_spte(vcpu, iterator.sptep);



		if (!is_shadow_present_pte(*iterator.sptep)) {

			u64 base_addr = iterator.addr;