KVM: PPC: Emulate dcbf

commit d3286144c92ec876da9e30320afa875699b7e0f1 upstream.

Guests can trigger MMIO exits using dcbf. Since we don't emulate cache
incoherent MMIO, just do nothing and move on.

Reported-by: Ben Collins <ben.c@servergy.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Tested-by: Ben Collins <ben.c@servergy.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 141dce3c6810839b65f519767c070d28c3c11fa0..2a73d821e1fc99dde6525c94b303172ac88910ba 100644 (file)
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -35,6 +35,7 @@
 #define OP_TRAP_64 2
 
 #define OP_31_XOP_LWZX      23
+#define OP_31_XOP_DCBF      86
 #define OP_31_XOP_LBZX      87
 #define OP_31_XOP_STWX      151
 #define OP_31_XOP_STBX      215
@@ -370,6 +371,7 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
                        kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
                        break;
 
+               case OP_31_XOP_DCBF:
                case OP_31_XOP_DCBI:
                        /* Do nothing. The guest is performing dcbi because
                         * hardware DMA is not snooped by the dcache, but