KVM: MIPS/MMU: Use lockless GVA helpers for get_inst()

Use the lockless GVA helpers to implement the reading of guest
instructions for emulation. This will allow it to handle asynchronous
TLB flushes when they are implemented.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

1 files changed, 18 insertions, 3 deletions

diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index 32c317de6c0a..b3da473e1569 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -787,11 +787,26 @@ int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
 {
         int err;
 
+retry:
+        kvm_trap_emul_gva_lockless_begin(vcpu);
         err = get_user(*out, opc);
+        kvm_trap_emul_gva_lockless_end(vcpu);
+
         if (unlikely(err)) {
-                kvm_err("%s: illegal address: %p\n", __func__, opc);
-                return -EFAULT;
-        }
+                /*
+                 * Try to handle the fault, maybe we just raced with a GVA
+                 * invalidation.
+                 */
+                err = kvm_trap_emul_gva_fault(vcpu, (unsigned long)opc,
+                                              false);
+                if (unlikely(err)) {
+                        kvm_err("%s: illegal address: %p\n",
+                                __func__, opc);
+                        return -EFAULT;
+                }
 
+                /* Hopefully it'll work now */
+                goto retry;
+        }
         return 0;
 }