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-rw-r--r--arch/mips/kvm/emulate.c52
1 files changed, 46 insertions, 6 deletions
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 5f0354c..f0fa9e9 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -161,9 +161,12 @@ unsigned long kvm_compute_return_epc(struct kvm_vcpu *vcpu,
nextpc = epc;
break;
- case blez_op: /* not really i_format */
- case blezl_op:
- /* rt field assumed to be zero */
+ case blez_op: /* POP06 */
+#ifndef CONFIG_CPU_MIPSR6
+ case blezl_op: /* removed in R6 */
+#endif
+ if (insn.i_format.rt != 0)
+ goto compact_branch;
if ((long)arch->gprs[insn.i_format.rs] <= 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
@@ -171,9 +174,12 @@ unsigned long kvm_compute_return_epc(struct kvm_vcpu *vcpu,
nextpc = epc;
break;
- case bgtz_op:
- case bgtzl_op:
- /* rt field assumed to be zero */
+ case bgtz_op: /* POP07 */
+#ifndef CONFIG_CPU_MIPSR6
+ case bgtzl_op: /* removed in R6 */
+#endif
+ if (insn.i_format.rt != 0)
+ goto compact_branch;
if ((long)arch->gprs[insn.i_format.rs] > 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
@@ -185,6 +191,40 @@ unsigned long kvm_compute_return_epc(struct kvm_vcpu *vcpu,
case cop1_op:
kvm_err("%s: unsupported cop1_op\n", __func__);
break;
+
+#ifdef CONFIG_CPU_MIPSR6
+ /* R6 added the following compact branches with forbidden slots */
+ case blezl_op: /* POP26 */
+ case bgtzl_op: /* POP27 */
+ /* only rt == 0 isn't compact branch */
+ if (insn.i_format.rt != 0)
+ goto compact_branch;
+ break;
+ case pop10_op:
+ case pop30_op:
+ /* only rs == rt == 0 is reserved, rest are compact branches */
+ if (insn.i_format.rs != 0 || insn.i_format.rt != 0)
+ goto compact_branch;
+ break;
+ case pop66_op:
+ case pop76_op:
+ /* only rs == 0 isn't compact branch */
+ if (insn.i_format.rs != 0)
+ goto compact_branch;
+ break;
+compact_branch:
+ /*
+ * If we've hit an exception on the forbidden slot, then
+ * the branch must not have been taken.
+ */
+ epc += 8;
+ nextpc = epc;
+ break;
+#else
+compact_branch:
+ /* Compact branches not supported before R6 */
+ break;
+#endif
}
return nextpc;