ipmi/bmc-sim: Add 'Get Channel Info' command

Linux issues this command when booting a powernv machine.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-ID: <20250401140153.685523-4-npiggin@gmail.com>
Signed-off-by: Corey Minyard <corey@minyard.net>

4 files changed, 79 insertions, 2 deletions

diff --git a/hw/ipmi/ipmi_bmc_sim.c b/hw/ipmi/ipmi_bmc_sim.c
index bc0ddc5..03e58d2 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 +1220,68 @@ 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);
+    IPMIFwInfo info = {};
+    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 (k->get_fwinfo) {
+        k->get_fwinfo(s, &info);
+    }
+
+    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, info.ipmi_channel_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) {
+        uint8_t irq;
+
+        if (info.irq_source == IPMI_ISA_IRQ) {
+            irq = info.interrupt_number;
+        } else if (info.irq_source == 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 +2078,7 @@ 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 583fc64..28cf6ab 100644
--- a/hw/ipmi/ipmi_bt.c
+++ b/hw/ipmi/ipmi_bt.c
@@ -419,6 +419,8 @@ void ipmi_bt_get_fwinfo(struct IPMIBT *ib, IPMIFwInfo *info)
     info->interface_type = IPMI_SMBIOS_BT;
     info->ipmi_spec_major_revision = 2;
     info->ipmi_spec_minor_revision = 0;
+    /* BT System Interface Format, IPMI v1.5 */
+    info->ipmi_channel_protocol = IPMI_CHANNEL_PROTOCOL_BT_15;
     info->base_address = ib->io_base;
     info->register_length = ib->io_length;
     info->register_spacing = 1;
diff --git a/hw/ipmi/ipmi_kcs.c b/hw/ipmi/ipmi_kcs.c
index c15977c..578dd7c 100644
--- a/hw/ipmi/ipmi_kcs.c
+++ b/hw/ipmi/ipmi_kcs.c
@@ -405,6 +405,7 @@ void ipmi_kcs_get_fwinfo(IPMIKCS *ik, IPMIFwInfo *info)
     info->interface_type = IPMI_SMBIOS_KCS;
     info->ipmi_spec_major_revision = 2;
     info->ipmi_spec_minor_revision = 0;
+    info->ipmi_channel_protocol = IPMI_CHANNEL_PROTOCOL_KCS;
     info->base_address = ik->io_base;
     info->i2c_slave_address = ik->bmc->slave_addr;
     info->register_length = ik->io_length;
diff --git a/include/hw/ipmi/ipmi.h b/include/hw/ipmi/ipmi.h
index c8ef048..802a2fe 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
@@ -76,6 +85,7 @@ typedef struct IPMIFwInfo {
     int interface_type;
     uint8_t ipmi_spec_major_revision;
     uint8_t ipmi_spec_minor_revision;
+    uint8_t ipmi_channel_protocol;
     uint8_t i2c_slave_address;
     uint32_t uuid;