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[02/26] target/ppc: Prevent supervisor from modifying MSR[ME]

Message ID 20240118150644.177371-3-npiggin@gmail.com
State New
Headers show
Series target/ppc: TCG improvements and fixes | expand

Commit Message

Nicholas Piggin Jan. 18, 2024, 3:06 p.m. UTC 
Prevent guest state modifying the MSR[ME] bit. Per ISA:

  An attempt to modify MSRME in privileged but non-hypervisor state is
  ignored (i.e., the bit is not changed).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/helper_regs.c | 5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
index e0b2dcd02e..bd17c14136 100644
--- a/target/ppc/helper_regs.c
+++ b/target/ppc/helper_regs.c
@@ -264,6 +264,11 @@  int hreg_store_msr(CPUPPCState *env, target_ulong value, int alter_hv)
         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);
     }