target/ppc: Prevent supervisor from modifying MSR[ME]
Prevent guest state modifying the MSR[ME] bit. Per ISA:
An attempt to modify MSR[ME] in privileged but non-hypervisor state
is ignored (i.e., the bit is not changed).
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
index 410b39c..2525898 100644
--- a/target/ppc/helper_regs.c
+++ b/target/ppc/helper_regs.c
@@ -264,6 +264,11 @@
value &= ~MSR_HVB;
value |= env->msr & MSR_HVB;
}
+ /* Attempt to modify MSR[ME] in guest state is ignored */
+ if (is_book3s_arch2x(env) && !(env->msr & MSR_HVB)) {
+ value &= ~(1 << MSR_ME);
+ value |= env->msr & (1 << MSR_ME);
+ }
if ((value ^ env->msr) & (R_MSR_IR_MASK | R_MSR_DR_MASK)) {
cpu_interrupt_exittb(cs);
}
