[PATCH 11/18] KVM: arm64: Convert to the gfn-based MMU notifier callbacks

From: Sean Christopherson
Date: Thu Mar 25 2021 - 22:21:24 EST


Move arm64 to the gfn-base MMU notifier APIs, which do the hva->gfn
lookup in common code.

Note, due to arch code being called if and only if a memslot is found,
the clean_dcache_guest_page() call in kvm_set_spte_*() is will no longer
be called for addresses that are not found in the guest memslots.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/kvm/mmu.c | 117 ++++++++----------------------
2 files changed, 33 insertions(+), 85 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 72e6b4600264..1ad729cf7b0d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -582,6 +582,7 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
struct kvm_vcpu_events *events);

#define KVM_ARCH_WANT_MMU_NOTIFIER
+#define KVM_ARCH_WANT_NEW_MMU_NOTIFIER_APIS

void kvm_arm_halt_guest(struct kvm *kvm);
void kvm_arm_resume_guest(struct kvm *kvm);
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 4b7e1e327337..35728231e9a0 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -839,7 +839,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
* gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk
* the page we just got a reference to gets unmapped before we have a
* chance to grab the mmu_lock, which ensure that if the page gets
- * unmapped afterwards, the call to kvm_unmap_hva will take it away
+ * unmapped afterwards, the call to kvm_unmap_gfn will take it away
* from us again properly. This smp_rmb() interacts with the smp_wmb()
* in kvm_mmu_notifier_invalidate_<page|range_end>.
*/
@@ -1064,123 +1064,70 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
return ret;
}

-static int handle_hva_to_gpa(struct kvm *kvm,
- unsigned long start,
- unsigned long end,
- int (*handler)(struct kvm *kvm,
- gpa_t gpa, u64 size,
- void *data),
- void *data)
-{
- struct kvm_memslots *slots;
- struct kvm_memory_slot *memslot;
- int ret = 0;
-
- slots = kvm_memslots(kvm);
-
- /* we only care about the pages that the guest sees */
- kvm_for_each_memslot(memslot, slots) {
- unsigned long hva_start, hva_end;
- gfn_t gpa;
-
- hva_start = max(start, memslot->userspace_addr);
- hva_end = min(end, memslot->userspace_addr +
- (memslot->npages << PAGE_SHIFT));
- if (hva_start >= hva_end)
- continue;
-
- gpa = hva_to_gfn_memslot(hva_start, memslot) << PAGE_SHIFT;
- ret |= handler(kvm, gpa, (u64)(hva_end - hva_start), data);
- }
-
- return ret;
-}
-
-static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
- unsigned flags = *(unsigned *)data;
- bool may_block = flags & MMU_NOTIFIER_RANGE_BLOCKABLE;
-
- __unmap_stage2_range(&kvm->arch.mmu, gpa, size, may_block);
- return 0;
-}
-
-int kvm_unmap_hva_range(struct kvm *kvm,
- unsigned long start, unsigned long end, unsigned flags)
+bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
{
if (!kvm->arch.mmu.pgt)
return 0;

- handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, &flags);
- return 0;
-}
+ __unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
+ (range->end - range->start) << PAGE_SHIFT,
+ range->may_block);

-static int kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
- kvm_pfn_t *pfn = (kvm_pfn_t *)data;
-
- WARN_ON(size != PAGE_SIZE);
-
- /*
- * The MMU notifiers will have unmapped a huge PMD before calling
- * ->change_pte() (which in turn calls kvm_set_spte_hva()) and
- * therefore we never need to clear out a huge PMD through this
- * calling path and a memcache is not required.
- */
- kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, gpa, PAGE_SIZE,
- __pfn_to_phys(*pfn), KVM_PGTABLE_PROT_R, NULL);
return 0;
}

-int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
+bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
- unsigned long end = hva + PAGE_SIZE;
- kvm_pfn_t pfn = pte_pfn(pte);
+ kvm_pfn_t pfn = pte_pfn(range->pte);

if (!kvm->arch.mmu.pgt)
return 0;

+ WARN_ON(range->end - range->start != 1);
+
/*
* We've moved a page around, probably through CoW, so let's treat it
* just like a translation fault and clean the cache to the PoC.
*/
clean_dcache_guest_page(pfn, PAGE_SIZE);
- handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pfn);
+
+ /*
+ * The MMU notifiers will have unmapped a huge PMD before calling
+ * ->change_pte() (which in turn calls kvm_set_spte_gfn()) and
+ * therefore we never need to clear out a huge PMD through this
+ * calling path and a memcache is not required.
+ */
+ kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, range->start << PAGE_SHIFT,
+ PAGE_SIZE, __pfn_to_phys(pfn),
+ KVM_PGTABLE_PROT_R, NULL);
+
return 0;
}

-static int kvm_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
+bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
- pte_t pte;
+ u64 size = (range->end - range->start) << PAGE_SHIFT;
kvm_pte_t kpte;
+ pte_t pte;
+
+ if (!kvm->arch.mmu.pgt)
+ return 0;

WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
- kpte = kvm_pgtable_stage2_mkold(kvm->arch.mmu.pgt, gpa);
+
+ kpte = kvm_pgtable_stage2_mkold(kvm->arch.mmu.pgt,
+ range->start << PAGE_SHIFT);
pte = __pte(kpte);
return pte_valid(pte) && pte_young(pte);
}

-static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
- WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
- return kvm_pgtable_stage2_is_young(kvm->arch.mmu.pgt, gpa);
-}
-
-int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
-{
- if (!kvm->arch.mmu.pgt)
- return 0;
-
- return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
-}
-
-int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
+bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
if (!kvm->arch.mmu.pgt)
return 0;

- return handle_hva_to_gpa(kvm, hva, hva + PAGE_SIZE,
- kvm_test_age_hva_handler, NULL);
+ return kvm_pgtable_stage2_is_young(kvm->arch.mmu.pgt,
+ range->start << PAGE_SHIFT);
}

phys_addr_t kvm_mmu_get_httbr(void)
--
2.31.0.291.g576ba9dcdaf-goog