[PATCH 5/7] KVM: arm64: Move 'invalid syndrome' logic out of io_mem_abort()

[Will Deacon]

In preparation for handling stage-2 faults on stage-1 page-table walks
earlier, move the 'invalid syndrome' logic out of io_mem_abort() and
into its own function, which can be called from kvm_handle_guest_abort()
directly.

Cc: Marc Zyngier <maz at kernel.org>
Cc: Quentin Perret <qperret at google.com>
Signed-off-by: Will Deacon <will at kernel.org>
---
 arch/arm64/kvm/mmio.c | 22 ----------------------
 arch/arm64/kvm/mmu.c  | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c
index b54ea5aa6c06..45a630e480e1 100644
--- a/arch/arm64/kvm/mmio.c
+++ b/arch/arm64/kvm/mmio.c
@@ -136,28 +136,6 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	int len;
 	u8 data_buf[8];
 
-	/*
-	 * No valid syndrome? Ask userspace for help if it has
-	 * volunteered to do so, and bail out otherwise.
-	 */
-	if (!kvm_vcpu_dabt_isvalid(vcpu)) {
-		if (vcpu->kvm->arch.return_nisv_io_abort_to_user) {
-			run->exit_reason = KVM_EXIT_ARM_NISV;
-			run->arm_nisv.esr_iss = kvm_vcpu_dabt_iss_nisv_sanitized(vcpu);
-			run->arm_nisv.fault_ipa = fault_ipa;
-			return 0;
-		}
-
-		kvm_pr_unimpl("Data abort outside memslots with no valid syndrome info\n");
-		return -ENOSYS;
-	}
-
-	/* Page table accesses IO mem: tell guest to fix its TTBR */
-	if (kvm_vcpu_dabt_iss1tw(vcpu)) {
-		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
-		return 1;
-	}
-
 	/*
 	 * Prepare MMIO operation. First decode the syndrome data we get
 	 * from the CPU. Then try if some in-kernel emulation feels
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 73e62d360a36..adb933ecd177 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -2046,6 +2046,20 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
 		kvm_set_pfn_accessed(pfn);
 }
 
+static int handle_error_invalid_dabt(struct kvm_vcpu *vcpu, struct kvm_run *run,
+				     phys_addr_t fault_ipa)
+{
+	if (!vcpu->kvm->arch.return_nisv_io_abort_to_user) {
+		kvm_pr_unimpl("Data abort outside memslots with no valid syndrome info\n");
+		return -ENOSYS;
+	}
+
+	run->exit_reason = KVM_EXIT_ARM_NISV;
+	run->arm_nisv.esr_iss = kvm_vcpu_dabt_iss_nisv_sanitized(vcpu);
+	run->arm_nisv.fault_ipa = fault_ipa;
+	return 0;
+}
+
 /**
  * kvm_handle_guest_abort - handles all 2nd stage aborts
  * @vcpu:	the VCPU pointer
@@ -2133,6 +2147,21 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		 * of the page size.
 		 */
 		fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1);
+
+		/*
+		 * No valid syndrome? Ask userspace for help if it has
+		 * volunteered to do so, and bail out otherwise.
+		 */
+		if (!kvm_vcpu_dabt_isvalid(vcpu)) {
+			ret = handle_error_invalid_dabt(vcpu, run, fault_ipa);
+			goto out_unlock;
+		}
+
+		if (kvm_vcpu_dabt_iss1tw(vcpu)) {
+			ret = -ENXIO;
+			goto out;
+		}
+
 		ret = io_mem_abort(vcpu, run, fault_ipa);
 		goto out_unlock;
 	}
@@ -2153,6 +2182,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	if (ret == -ENOEXEC) {
 		kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
 		ret = 1;
+	} else if (ret == -ENXIO) {
+		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
+		ret = 1;
 	}
 out_unlock:
 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
-- 
2.28.0.rc0.142.g3c755180ce-goog