kvm: x86/mmu: Support changed pte notifier in tdp MMU

In order to interoperate correctly with the rest of KVM and other Linux
subsystems, the TDP MMU must correctly handle various MMU notifiers. Add
a hook and handle the change_pte MMU notifier.

Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell
machine. This series introduced no new failures.

This series can be viewed in Gerrit at:
	https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20201014182700.2888246-15-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 33ec6c4c36d7e0998b3cde458b6822e6dee2e437..41f0354c748928354cc6d92073bcf3012e170fed 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1509,7 +1509,14 @@ int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end,
 
 int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
 {
-       return kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
+       int r;
+
+       r = kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
+
+       if (kvm->arch.tdp_mmu_enabled)
+               r |= kvm_tdp_mmu_set_spte_hva(kvm, hva, &pte);
+
+       return r;
 }
 
 static int kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index dd6b8a8f1c933788a85d43316d5b98ef87ec0426..64e640cfcff92e12be6c9471e91dd4d4efb87006 100644 (file)
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -671,3 +671,59 @@ int kvm_tdp_mmu_test_age_hva(struct kvm *kvm, unsigned long hva)
        return kvm_tdp_mmu_handle_hva_range(kvm, hva, hva + 1, 0,
                                            test_age_gfn);
 }
+
+/*
+ * Handle the changed_pte MMU notifier for the TDP MMU.
+ * data is a pointer to the new pte_t mapping the HVA specified by the MMU
+ * notifier.
+ * Returns non-zero if a flush is needed before releasing the MMU lock.
+ */
+static int set_tdp_spte(struct kvm *kvm, struct kvm_memory_slot *slot,
+                       struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused,
+                       unsigned long data)
+{
+       struct tdp_iter iter;
+       pte_t *ptep = (pte_t *)data;
+       kvm_pfn_t new_pfn;
+       u64 new_spte;
+       int need_flush = 0;
+
+       WARN_ON(pte_huge(*ptep));
+
+       new_pfn = pte_pfn(*ptep);
+
+       tdp_root_for_each_pte(iter, root, gfn, gfn + 1) {
+               if (iter.level != PG_LEVEL_4K)
+                       continue;
+
+               if (!is_shadow_present_pte(iter.old_spte))
+                       break;
+
+               tdp_mmu_set_spte(kvm, &iter, 0);
+
+               kvm_flush_remote_tlbs_with_address(kvm, iter.gfn, 1);
+
+               if (!pte_write(*ptep)) {
+                       new_spte = kvm_mmu_changed_pte_notifier_make_spte(
+                                       iter.old_spte, new_pfn);
+
+                       tdp_mmu_set_spte(kvm, &iter, new_spte);
+               }
+
+               need_flush = 1;
+       }
+
+       if (need_flush)
+               kvm_flush_remote_tlbs_with_address(kvm, gfn, 1);
+
+       return 0;
+}
+
+int kvm_tdp_mmu_set_spte_hva(struct kvm *kvm, unsigned long address,
+                            pte_t *host_ptep)
+{
+       return kvm_tdp_mmu_handle_hva_range(kvm, address, address + 1,
+                                           (unsigned long)host_ptep,
+                                           set_tdp_spte);
+}
+

diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index ddc1bf12d0fc0dc39703104bcdf6d68e728cca71..aeee3ce7b3f4a0f394b594bf6811c9d37a87357d 100644 (file)
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -25,4 +25,7 @@ int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start,
 int kvm_tdp_mmu_age_hva_range(struct kvm *kvm, unsigned long start,
                              unsigned long end);
 int kvm_tdp_mmu_test_age_hva(struct kvm *kvm, unsigned long hva);
+
+int kvm_tdp_mmu_set_spte_hva(struct kvm *kvm, unsigned long address,
+                            pte_t *host_ptep);
 #endif /* __KVM_X86_MMU_TDP_MMU_H */