@@ -1508,6 +1508,89 @@ static void adjust_nested_fault_perms(struct kvm_s2_trans *nested,
*prot |= kvm_encode_nested_level(nested);
}
+#define KVM_PGTABLE_WALK_MEMABORT_FLAGS (KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED)
+
+static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
+ struct kvm_s2_trans *nested,
+ struct kvm_memory_slot *memslot, bool is_perm)
+{
+ bool logging, write_fault, exec_fault, writable;
+ enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_MEMABORT_FLAGS;
+ enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
+ struct kvm_pgtable *pgt = vcpu->arch.hw_mmu->pgt;
+ struct page *page;
+ struct kvm *kvm = vcpu->kvm;
+ void *memcache;
+ kvm_pfn_t pfn;
+ gfn_t gfn;
+ int ret;
+
+ ret = prepare_mmu_memcache(vcpu, !is_perm, &memcache);
+ if (ret)
+ return ret;
+
+ if (nested)
+ gfn = kvm_s2_trans_output(nested) >> PAGE_SHIFT;
+ else
+ gfn = fault_ipa >> PAGE_SHIFT;
+
+ logging = memslot_is_logging(memslot);
+ write_fault = kvm_is_write_fault(vcpu);
+ exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
+
+ if (write_fault && exec_fault) {
+ kvm_err("Simultaneous write and execution fault\n");
+ return -EFAULT;
+ }
+
+ if (is_perm && !write_fault && !exec_fault) {
+ kvm_err("Unexpected L2 read permission error\n");
+ return -EFAULT;
+ }
+
+ ret = kvm_gmem_get_pfn(kvm, memslot, gfn, &pfn, &page, NULL);
+ if (ret) {
+ kvm_prepare_memory_fault_exit(vcpu, fault_ipa, PAGE_SIZE,
+ write_fault, exec_fault, false);
+ return ret;
+ }
+
+ writable = !(memslot->flags & KVM_MEM_READONLY) &&
+ (!logging || write_fault);
+
+ if (nested)
+ adjust_nested_fault_perms(nested, &prot, &writable);
+
+ if (writable)
+ prot |= KVM_PGTABLE_PROT_W;
+
+ if (exec_fault ||
+ (cpus_have_final_cap(ARM64_HAS_CACHE_DIC) &&
+ (!nested || kvm_s2_trans_executable(nested))))
+ prot |= KVM_PGTABLE_PROT_X;
+
+ kvm_fault_lock(kvm);
+ if (is_perm) {
+ /*
+ * Drop the SW bits in favour of those stored in the
+ * PTE, which will be preserved.
+ */
+ prot &= ~KVM_NV_GUEST_MAP_SZ;
+ ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, fault_ipa, prot, flags);
+ } else {
+ ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, fault_ipa, PAGE_SIZE,
+ __pfn_to_phys(pfn), prot,
+ memcache, flags);
+ }
+ kvm_release_faultin_page(kvm, page, !!ret, writable);
+ kvm_fault_unlock(kvm);
+
+ if (writable && !ret)
+ mark_page_dirty_in_slot(kvm, memslot, gfn);
+
+ return ret != -EAGAIN ? ret : 0;
+}
+
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
struct kvm_s2_trans *nested,
struct kvm_memory_slot *memslot, unsigned long hva,
@@ -1532,7 +1615,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
struct kvm_pgtable *pgt;
struct page *page;
- enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED;
+ enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_MEMABORT_FLAGS;
if (fault_is_perm)
fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
@@ -1959,8 +2042,12 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
goto out_unlock;
}
- ret = user_mem_abort(vcpu, fault_ipa, nested, memslot, hva,
- esr_fsc_is_permission_fault(esr));
+ if (kvm_slot_has_gmem(memslot))
+ ret = gmem_abort(vcpu, fault_ipa, nested, memslot,
+ esr_fsc_is_permission_fault(esr));
+ else
+ ret = user_mem_abort(vcpu, fault_ipa, nested, memslot, hva,
+ esr_fsc_is_permission_fault(esr));
if (ret == 0)
ret = 1;
out:
Add arm64 support for handling guest page faults on guest_memfd backed memslots. Until guest_memfd supports huge pages, the fault granule is restricted to PAGE_SIZE. Signed-off-by: Fuad Tabba <tabba@google.com> --- arch/arm64/kvm/mmu.c | 93 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 3 deletions(-)