Mask out unsupported bits and return failure if attempting to set
any. This is not required by the IPMI spec, but it does require that
system software not change bits it isn't aware of.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 hw/ipmi/ipmi_bmc_sim.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/hw/ipmi/ipmi_bmc_sim.c b/hw/ipmi/ipmi_bmc_sim.c
index 32161044c0b..8c3313aa65f 100644
--- a/hw/ipmi/ipmi_bmc_sim.c
+++ b/hw/ipmi/ipmi_bmc_sim.c
@@ -234,6 +234,7 @@ struct IPMIBmcSim {
 #define IPMI_BMC_MSG_FLAG_RCV_MSG_QUEUE_SET(s) \
     (IPMI_BMC_MSG_FLAG_RCV_MSG_QUEUE & (s)->msg_flags)
 
+#define IPMI_BMC_GLOBAL_ENABLES_SUPPORTED 0x0f
 #define IPMI_BMC_RCV_MSG_QUEUE_INT_BIT    0
 #define IPMI_BMC_EVBUF_FULL_INT_BIT       1
 #define IPMI_BMC_EVENT_MSG_BUF_BIT        2
@@ -930,7 +931,14 @@ static void set_bmc_global_enables(IPMIBmcSim *ibs,
                                    uint8_t *cmd, unsigned int cmd_len,
                                    RspBuffer *rsp)
 {
-    set_global_enables(ibs, cmd[2]);
+    uint8_t val = cmd[2];
+
+    if (val & ~IPMI_BMC_GLOBAL_ENABLES_SUPPORTED) {
+        rsp_buffer_set_error(rsp, IPMI_CC_INVALID_DATA_FIELD);
+        return;
+    }
+
+    set_global_enables(ibs, val);
 }
 
 static void get_bmc_global_enables(IPMIBmcSim *ibs,
-- 
2.47.1