Linux issues this command when booting a powernv machine.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 include/hw/ipmi/ipmi.h | 14 +++++++++
 hw/ipmi/ipmi_bmc_sim.c | 65 ++++++++++++++++++++++++++++++++++++++++--
 hw/ipmi/ipmi_bt.c      |  2 ++
 hw/ipmi/ipmi_kcs.c     |  1 +
 4 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/include/hw/ipmi/ipmi.h b/include/hw/ipmi/ipmi.h
index 71c4efac8cd..d1af660012a 100644
--- a/include/hw/ipmi/ipmi.h
+++ b/include/hw/ipmi/ipmi.h
@@ -41,6 +41,15 @@ enum ipmi_op {
     IPMI_SEND_NMI
 };
 
+/* Channel properties */
+#define IPMI_CHANNEL_IPMB                0x00
+#define IPMI_CHANNEL_SYSTEM              0x0f
+#define IPMI_CHANNEL_MEDIUM_IPMB         0x01
+#define IPMI_CHANNEL_MEDIUM_SYSTEM       0x0c
+#define IPMI_CHANNEL_PROTOCOL_IPMB       0x01
+#define IPMI_CHANNEL_PROTOCOL_KCS        0x05
+#define IPMI_CHANNEL_PROTOCOL_BT_15      0x08
+
 #define IPMI_CC_INVALID_CMD                              0xc1
 #define IPMI_CC_COMMAND_INVALID_FOR_LUN                  0xc2
 #define IPMI_CC_TIMEOUT                                  0xc3
@@ -175,6 +184,11 @@ struct IPMIInterfaceClass {
      * Return the firmware info for a device.
      */
     void (*get_fwinfo)(struct IPMIInterface *s, IPMIFwInfo *info);
+
+    /*
+     * IPMI channel protocol type number.
+     */
+    uint8_t protocol;
 };
 
 /*
diff --git a/hw/ipmi/ipmi_bmc_sim.c b/hw/ipmi/ipmi_bmc_sim.c
index 6157ac71201..216bf8ff7f0 100644
--- a/hw/ipmi/ipmi_bmc_sim.c
+++ b/hw/ipmi/ipmi_bmc_sim.c
@@ -70,6 +70,7 @@
 #define IPMI_CMD_GET_MSG                  0x33
 #define IPMI_CMD_SEND_MSG                 0x34
 #define IPMI_CMD_READ_EVT_MSG_BUF         0x35
+#define IPMI_CMD_GET_CHANNEL_INFO         0x42
 
 #define IPMI_NETFN_STORAGE            0x0a
 
@@ -1020,8 +1021,8 @@ static void send_msg(IPMIBmcSim *ibs,
     uint8_t *buf;
     uint8_t netfn, rqLun, rsLun, rqSeq;
 
-    if (cmd[2] != 0) {
-        /* We only handle channel 0 with no options */
+    if (cmd[2] != IPMI_CHANNEL_IPMB) {
+        /* We only handle channel 0h (IPMB) with no options */
         rsp_buffer_set_error(rsp, IPMI_CC_INVALID_DATA_FIELD);
         return;
     }
@@ -1219,6 +1220,65 @@ static void get_watchdog_timer(IPMIBmcSim *ibs,
     }
 }
 
+static void get_channel_info(IPMIBmcSim *ibs,
+                             uint8_t *cmd, unsigned int cmd_len,
+                             RspBuffer *rsp)
+{
+    IPMIInterface *s = ibs->parent.intf;
+    IPMIInterfaceClass *k = IPMI_INTERFACE_GET_CLASS(s);
+    uint8_t ch = cmd[2] & 0x0f;
+
+    /* Only define channel 0h (IPMB) and Fh (system interface) */
+
+    if (ch == 0x0e) { /* "This channel" */
+        ch = IPMI_CHANNEL_SYSTEM;
+    }
+    rsp_buffer_push(rsp, ch);
+
+    if (ch != IPMI_CHANNEL_IPMB && ch != IPMI_CHANNEL_SYSTEM) {
+        /* Not a supported channel */
+        rsp_buffer_set_error(rsp, IPMI_CC_INVALID_DATA_FIELD);
+        return;
+    }
+
+    if (ch == IPMI_CHANNEL_IPMB) {
+        rsp_buffer_push(rsp, IPMI_CHANNEL_MEDIUM_IPMB);
+        rsp_buffer_push(rsp, IPMI_CHANNEL_PROTOCOL_IPMB);
+    } else { /* IPMI_CHANNEL_SYSTEM */
+        rsp_buffer_push(rsp, IPMI_CHANNEL_MEDIUM_SYSTEM);
+        rsp_buffer_push(rsp, k->protocol);
+    }
+
+    rsp_buffer_push(rsp, 0x00); /* Session-less */
+
+    /* IPMI Enterprise Number for Vendor ID */
+    rsp_buffer_push(rsp, 0xf2);
+    rsp_buffer_push(rsp, 0x1b);
+    rsp_buffer_push(rsp, 0x00);
+
+    if (ch == IPMI_CHANNEL_SYSTEM) {
+        IPMIFwInfo info = {};
+        uint8_t irq;
+
+        k->get_fwinfo(s, &info);
+        if (info.irq == IPMI_ISA_IRQ) {
+            irq = info.interrupt_number;
+	} else if (info.irq == IPMI_PCI_IRQ) {
+            irq = 0x10 + info.interrupt_number;
+        } else {
+            irq = 0xff; /* no interrupt / unspecified */
+        }
+
+        /* Both interrupts use the same irq number */
+        rsp_buffer_push(rsp, irq);
+        rsp_buffer_push(rsp, irq);
+    } else {
+        /* Reserved */
+        rsp_buffer_push(rsp, 0x00);
+        rsp_buffer_push(rsp, 0x00);
+    }
+}
+
 static void get_sdr_rep_info(IPMIBmcSim *ibs,
                              uint8_t *cmd, unsigned int cmd_len,
                              RspBuffer *rsp)
@@ -2015,6 +2075,7 @@ static const IPMICmdHandler app_cmds[] = {
     [IPMI_CMD_RESET_WATCHDOG_TIMER] = { reset_watchdog_timer },
     [IPMI_CMD_SET_WATCHDOG_TIMER] = { set_watchdog_timer, 8 },
     [IPMI_CMD_GET_WATCHDOG_TIMER] = { get_watchdog_timer },
+    [IPMI_CMD_GET_CHANNEL_INFO] = { get_channel_info, 3 },
 };
 static const IPMINetfn app_netfn = {
     .cmd_nums = ARRAY_SIZE(app_cmds),
diff --git a/hw/ipmi/ipmi_bt.c b/hw/ipmi/ipmi_bt.c
index 583fc64730c..79311c41f2b 100644
--- a/hw/ipmi/ipmi_bt.c
+++ b/hw/ipmi/ipmi_bt.c
@@ -434,4 +434,6 @@ void ipmi_bt_class_init(IPMIInterfaceClass *iic)
     iic->handle_if_event = ipmi_bt_handle_event;
     iic->set_irq_enable = ipmi_bt_set_irq_enable;
     iic->reset = ipmi_bt_handle_reset;
+    /* BT System Interface Format, IPMI v1.5 */
+    iic->protocol = IPMI_CHANNEL_PROTOCOL_BT_15;
 }
diff --git a/hw/ipmi/ipmi_kcs.c b/hw/ipmi/ipmi_kcs.c
index c15977cab4c..618a33c581f 100644
--- a/hw/ipmi/ipmi_kcs.c
+++ b/hw/ipmi/ipmi_kcs.c
@@ -420,4 +420,5 @@ void ipmi_kcs_class_init(IPMIInterfaceClass *iic)
     iic->handle_rsp = ipmi_kcs_handle_rsp;
     iic->handle_if_event = ipmi_kcs_handle_event;
     iic->set_irq_enable = ipmi_kcs_set_irq_enable;
+    iic->protocol = IPMI_CHANNEL_PROTOCOL_KCS;
 }
-- 
2.47.1