[v4,1/3] msix/hmp: add hmp interface to dump MSI-X info

Commit Message

Dongli Zhang July 14, 2021, 4:56 p.m. UTC

This patch is to add the HMP interface to dump MSI-X table and PBA, in
order to help diagnose the loss of IRQ issue in VM (e.g., if an MSI-X
vector is erroneously masked permanently). Here is the example with
vhost-scsi:

(qemu) info msix /machine/peripheral/vscsi0
Msg L.Addr Msg U.Addr Msg Data   Vect Ctrl
0xfee00000 0x00000000 0x00004041 0x00000000
0xfee00000 0x00000000 0x00004051 0x00000000
0xfee00000 0x00000000 0x00004061 0x00000000
0xfee00000 0x00000000 0x00004071 0x00000000
0xfee01000 0x00000000 0x000040b1 0x00000000
0xfee02000 0x00000000 0x000040c1 0x00000000
0xfee03000 0x00000000 0x000040d1 0x00000000

MSI-X PBA
0 0 0 0 0 0 0

Since this is just for debugging by humans, provide the command only in
HMP, not in QMP.

Cc: Jason Wang <[e-mail]>
Cc: Joe Jin <[e-mail]>
Signed-off-by: Dongli Zhang <[e-mail]>
Acked-by: Dr. David Alan Gilbert <[e-mail]>
Acked-by: Jason Wang <[e-mail]>
---
Changed since v1/v2:
  - Add msix_present() to pci-stub.c to avoid build error
Changed since v3:
  - Rework commit message to explain why only HMP (suggested by Markus
    Armbruster)

 hmp-commands-info.hx   | 13 +++++++++
 hw/pci/msix.c          | 63 ++++++++++++++++++++++++++++++++++++++++++
 hw/pci/pci-stub.c      |  5 ++++
 include/hw/pci/msix.h  |  2 ++
 include/monitor/hmp.h  |  1 +
 softmmu/qdev-monitor.c | 25 +++++++++++++++++
 6 files changed, 109 insertions(+)

Patch

diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index 27206ac049..ce5c550d44 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -221,6 +221,19 @@  SRST
     Show PCI information.
 ERST
 
+    {
+        .name       = "msix",
+        .args_type  = "dev:s",
+        .params     = "dev",
+        .help       = "dump MSI-X information",
+        .cmd        = hmp_info_msix,
+    },
+
+SRST
+  ``info msix`` *dev*
+    Dump MSI-X information for device *dev*.
+ERST
+
 #if defined(TARGET_I386) || defined(TARGET_SH4) || defined(TARGET_SPARC) || \
     defined(TARGET_PPC) || defined(TARGET_XTENSA) || defined(TARGET_M68K)
     {
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index ae9331cd0b..4b4ec87eee 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -22,6 +22,7 @@ 
 #include "sysemu/xen.h"
 #include "migration/qemu-file-types.h"
 #include "migration/vmstate.h"
+#include "monitor/monitor.h"
 #include "qemu/range.h"
 #include "qapi/error.h"
 #include "trace.h"
@@ -669,3 +670,65 @@  const VMStateDescription vmstate_msix = {
         VMSTATE_END_OF_LIST()
     }
 };
+
+static void msix_dump_table(Monitor *mon, PCIDevice *dev)
+{
+    int vector;
+    uint32_t val;
+    uint8_t *table_entry;
+
+    monitor_printf(mon, "Msg L.Addr ");
+    monitor_printf(mon, "Msg U.Addr ");
+    monitor_printf(mon, "Msg Data   ");
+    monitor_printf(mon, "Vect Ctrl\n");
+
+    for (vector = 0; vector < dev->msix_entries_nr; vector++) {
+        table_entry = dev->msix_table + vector * PCI_MSIX_ENTRY_SIZE;
+
+        val = pci_get_long(table_entry + PCI_MSIX_ENTRY_LOWER_ADDR);
+        monitor_printf(mon, "0x%08x ", val);
+
+        val = pci_get_long(table_entry + PCI_MSIX_ENTRY_UPPER_ADDR);
+        monitor_printf(mon, "0x%08x ", val);
+
+        val = pci_get_long(table_entry + PCI_MSIX_ENTRY_DATA);
+        monitor_printf(mon, "0x%08x ", val);
+
+        val = pci_get_long(table_entry + PCI_MSIX_ENTRY_VECTOR_CTRL);
+        monitor_printf(mon, "0x%08x\n", val);
+    }
+
+    monitor_printf(mon, "\n");
+}
+
+static void msix_dump_pba(Monitor *mon, PCIDevice *dev)
+{
+    int vector;
+
+    monitor_printf(mon, "MSI-X PBA\n");
+
+    for (vector = 0; vector < dev->msix_entries_nr; vector++) {
+        monitor_printf(mon, "%d ", !!msix_is_pending(dev, vector));
+
+        if (vector % 16 == 15) {
+            monitor_printf(mon, "\n");
+        }
+    }
+
+    if (vector % 16 != 15) {
+        monitor_printf(mon, "\n");
+    }
+
+    monitor_printf(mon, "\n");
+}
+
+void msix_dump_info(Monitor *mon, PCIDevice *dev, Error **errp)
+{
+    if (!msix_present(dev)) {
+        error_setg(errp, "MSI-X not available");
+        return;
+    }
+
+    msix_dump_table(mon, dev);
+    msix_dump_pba(mon, dev);
+}
diff --git a/hw/pci/pci-stub.c b/hw/pci/pci-stub.c
index 3a027c42e4..8191d49d56 100644
--- a/hw/pci/pci-stub.c
+++ b/hw/pci/pci-stub.c
@@ -91,3 +91,8 @@  MSIMessage msix_get_message(PCIDevice *dev, unsigned int vector)
 {
     g_assert_not_reached();
 }
+
+void msix_dump_info(Monitor *mon, PCIDevice *dev, Error **errp)
+{
+     monitor_printf(mon, "PCI devices not supported\n");
+}
diff --git a/include/hw/pci/msix.h b/include/hw/pci/msix.h
index 4c4a60c739..10a4500295 100644
--- a/include/hw/pci/msix.h
+++ b/include/hw/pci/msix.h
@@ -47,6 +47,8 @@  int msix_set_vector_notifiers(PCIDevice *dev,
                               MSIVectorPollNotifier poll_notifier);
 void msix_unset_vector_notifiers(PCIDevice *dev);
 
+void msix_dump_info(Monitor *mon, PCIDevice *dev, Error **errp);
+
 extern const VMStateDescription vmstate_msix;
 
 #define VMSTATE_MSIX_TEST(_field, _state, _test) {                   \
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 3baa1058e2..97c040a3c8 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -36,6 +36,7 @@  void hmp_info_irq(Monitor *mon, const QDict *qdict);
 void hmp_info_pic(Monitor *mon, const QDict *qdict);
 void hmp_info_rdma(Monitor *mon, const QDict *qdict);
 void hmp_info_pci(Monitor *mon, const QDict *qdict);
+void hmp_info_msix(Monitor *mon, const QDict *qdict);
 void hmp_info_tpm(Monitor *mon, const QDict *qdict);
 void hmp_info_iothreads(Monitor *mon, const QDict *qdict);
 void hmp_quit(Monitor *mon, const QDict *qdict);
diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
index 721dec2d82..7837a17d0d 100644
--- a/softmmu/qdev-monitor.c
+++ b/softmmu/qdev-monitor.c
@@ -19,6 +19,7 @@ 
 
 #include "qemu/osdep.h"
 #include "hw/sysbus.h"
+#include "hw/pci/msix.h"
 #include "monitor/hmp.h"
 #include "monitor/monitor.h"
 #include "monitor/qdev.h"
@@ -1005,3 +1006,27 @@  bool qmp_command_available(const QmpCommand *cmd, Error **errp)
     }
     return true;
 }
+
+void hmp_info_msix(Monitor *mon, const QDict *qdict)
+{
+    const char *name = qdict_get_str(qdict, "dev");
+    DeviceState *dev = find_device_state(name, NULL);
+    PCIDevice *pci_dev;
+    Error *err = NULL;
+
+    if (!dev) {
+        error_setg(&err, "Device %s not found", name);
+        goto exit;
+    }
+
+    if (!object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+        error_setg(&err, "Not a PCI device");
+        goto exit;
+    }
+
+    pci_dev = PCI_DEVICE(dev);
+    msix_dump_info(mon, pci_dev, &err);
+
+exit:
+    hmp_handle_error(mon, err);
+}