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-rw-r--r--arch/powerpc/include/asm/kvm_book3s_64.h10
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_radix.c35
2 files changed, 39 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index c58e64a0a74f..9bb9bb370b53 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -635,6 +635,16 @@ extern void kvmhv_remove_nest_rmap_range(struct kvm *kvm,
unsigned long gpa, unsigned long hpa,
unsigned long nbytes);
+static inline pte_t *
+find_kvm_secondary_pte_unlocked(struct kvm *kvm, unsigned long ea,
+ unsigned *hshift)
+{
+ pte_t *pte;
+
+ pte = __find_linux_pte(kvm->arch.pgtable, ea, NULL, hshift);
+ return pte;
+}
+
static inline pte_t *find_kvm_secondary_pte(struct kvm *kvm, unsigned long ea,
unsigned *hshift)
{
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 271f1c3d8443..954fd7a12149 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -1040,7 +1040,7 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm,
{
unsigned long gfn = memslot->base_gfn + pagenum;
unsigned long gpa = gfn << PAGE_SHIFT;
- pte_t *ptep;
+ pte_t *ptep, pte;
unsigned int shift;
int ret = 0;
unsigned long old, *rmapp;
@@ -1048,12 +1048,35 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm,
if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
return ret;
- ptep = find_kvm_secondary_pte(kvm, gpa, &shift);
- if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
- ret = 1;
- if (shift)
- ret = 1 << (shift - PAGE_SHIFT);
+ /*
+ * For performance reasons we don't hold kvm->mmu_lock while walking the
+ * partition scoped table.
+ */
+ ptep = find_kvm_secondary_pte_unlocked(kvm, gpa, &shift);
+ if (!ptep)
+ return 0;
+
+ pte = READ_ONCE(*ptep);
+ if (pte_present(pte) && pte_dirty(pte)) {
spin_lock(&kvm->mmu_lock);
+ /*
+ * Recheck the pte again
+ */
+ if (pte_val(pte) != pte_val(*ptep)) {
+ /*
+ * We have KVM_MEM_LOG_DIRTY_PAGES enabled. Hence we can
+ * only find PAGE_SIZE pte entries here. We can continue
+ * to use the pte addr returned by above page table
+ * walk.
+ */
+ if (!pte_present(*ptep) || !pte_dirty(*ptep)) {
+ spin_unlock(&kvm->mmu_lock);
+ return 0;
+ }
+ }
+
+ ret = 1;
+ VM_BUG_ON(shift);
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0,
gpa, shift);
kvmppc_radix_tlbie_page(kvm, gpa, shift, kvm->arch.lpid);