hw/pci: add some convenient trace-events for pcie and shpc hotplug

Add trace-events that may help to debug problems with hotplugging.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240301154146.761531-2-vsementsov@yandex-team.ru>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/pci/pcie.c

@@ -28,6 +28,7 @@
 #include "hw/pci/pcie_regs.h"
 #include "hw/pci/pcie_port.h"
 #include "qemu/range.h"
+#include "trace.h"
 
 //#define DEBUG_PCIE
 #ifdef DEBUG_PCIE
@@ -45,6 +46,23 @@ static bool pcie_sltctl_powered_off(uint16_t sltctl)
         && (sltctl & PCI_EXP_SLTCTL_PIC) == PCI_EXP_SLTCTL_PWR_IND_OFF;
 }
 
+static const char *pcie_led_state_to_str(uint16_t value)
+{
+    switch (value) {
+    case PCI_EXP_SLTCTL_PWR_IND_ON:
+    case PCI_EXP_SLTCTL_ATTN_IND_ON:
+        return "on";
+    case PCI_EXP_SLTCTL_PWR_IND_BLINK:
+    case PCI_EXP_SLTCTL_ATTN_IND_BLINK:
+        return "blink";
+    case PCI_EXP_SLTCTL_PWR_IND_OFF:
+    case PCI_EXP_SLTCTL_ATTN_IND_OFF:
+        return "off";
+    default:
+        return "invalid";
+    }
+}
+
 /***************************************************************************
  * pci express capability helper functions
  */
@@ -735,6 +753,28 @@ void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slt_ctl, uint16_t *slt_sta)
     *slt_sta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
 }
 
+static void find_child_fn(PCIBus *bus, PCIDevice *dev, void *opaque)
+{
+    PCIDevice **child = opaque;
+
+    if (!*child) {
+        *child = dev;
+    }
+}
+
+/*
+ * Returns the plugged device or first function of multifunction plugged device
+ */
+static PCIDevice *pcie_cap_slot_find_child(PCIDevice *dev)
+{
+    PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
+    PCIDevice *child = NULL;
+
+    pci_for_each_device(sec_bus, pci_bus_num(sec_bus), find_child_fn, &child);
+
+    return child;
+}
+
 void pcie_cap_slot_write_config(PCIDevice *dev,
                                 uint16_t old_slt_ctl, uint16_t old_slt_sta,
                                 uint32_t addr, uint32_t val, int len)
@@ -779,6 +819,22 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
                         sltsta);
     }
 
+    if (trace_event_get_state_backends(TRACE_PCIE_CAP_SLOT_WRITE_CONFIG)) {
+        DeviceState *parent = DEVICE(dev);
+        DeviceState *child = DEVICE(pcie_cap_slot_find_child(dev));
+
+        trace_pcie_cap_slot_write_config(
+            parent->canonical_path,
+            child ? child->canonical_path : "no-child",
+            (sltsta & PCI_EXP_SLTSTA_PDS) ? "present" : "not present",
+            pcie_led_state_to_str(old_slt_ctl & PCI_EXP_SLTCTL_PIC),
+            pcie_led_state_to_str(val & PCI_EXP_SLTCTL_PIC),
+            pcie_led_state_to_str(old_slt_ctl & PCI_EXP_SLTCTL_AIC),
+            pcie_led_state_to_str(val & PCI_EXP_SLTCTL_AIC),
+            (old_slt_ctl & PCI_EXP_SLTCTL_PWR_OFF) ? "off" : "on",
+            (val & PCI_EXP_SLTCTL_PWR_OFF) ? "off" : "on");
+    }
+
     /*
      * If the slot is populated, power indicator is off and power
      * controller is off, it is safe to detach the devices.

hw/pci/shpc.c

@@ -8,6 +8,7 @@
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_bus.h"
 #include "hw/pci/msi.h"
+#include "trace.h"
 
 /* TODO: model power only and disabled slot states. */
 /* TODO: handle SERR and wakeups */
@@ -123,6 +124,34 @@
 #define SHPC_PCI_TO_IDX(pci_slot) ((pci_slot) - 1)
 #define SHPC_IDX_TO_PHYSICAL(slot) ((slot) + 1)
 
+static const char *shpc_led_state_to_str(uint8_t value)
+{
+    switch (value) {
+    case SHPC_LED_ON:
+        return "on";
+    case SHPC_LED_BLINK:
+        return "blink";
+    case SHPC_LED_OFF:
+        return "off";
+    default:
+        return "invalid";
+    }
+}
+
+static const char *shpc_slot_state_to_str(uint8_t value)
+{
+    switch (value) {
+    case SHPC_STATE_PWRONLY:
+        return "power-only";
+    case SHPC_STATE_ENABLED:
+        return "enabled";
+    case SHPC_STATE_DISABLED:
+        return "disabled";
+    default:
+        return "invalid";
+    }
+}
+
 static uint8_t shpc_get_status(SHPCDevice *shpc, int slot, uint16_t msk)
 {
     uint8_t *status = shpc->config + SHPC_SLOT_STATUS(slot);
@@ -302,6 +331,23 @@ static void shpc_slot_command(PCIDevice *d, uint8_t target,
         shpc_set_status(shpc, slot, state, SHPC_SLOT_STATE_MASK);
     }
 
+    if (trace_event_get_state_backends(TRACE_SHPC_SLOT_COMMAND)) {
+        DeviceState *parent = DEVICE(d);
+        int pci_slot = SHPC_IDX_TO_PCI(slot);
+        DeviceState *child =
+            DEVICE(shpc->sec_bus->devices[PCI_DEVFN(pci_slot, 0)]);
+
+        trace_shpc_slot_command(
+            parent->canonical_path, pci_slot,
+            child ? child->canonical_path : "no-child",
+            shpc_led_state_to_str(old_power),
+            shpc_led_state_to_str(power),
+            shpc_led_state_to_str(old_attn),
+            shpc_led_state_to_str(attn),
+            shpc_slot_state_to_str(old_state),
+            shpc_slot_state_to_str(state));
+    }
+
     if (!shpc_slot_is_off(old_state, old_power, old_attn) &&
         shpc_slot_is_off(state, power, attn))
     {

hw/pci/trace-events

@@ -16,3 +16,9 @@ msix_write_config(char *name, bool enabled, bool masked) "dev %s enabled %d mask
 sriov_register_vfs(const char *name, int slot, int function, int num_vfs) "%s %02x:%x: creating %d vf devs"
 sriov_unregister_vfs(const char *name, int slot, int function, int num_vfs) "%s %02x:%x: Unregistering %d vf devs"
 sriov_config_write(const char *name, int slot, int fun, uint32_t offset, uint32_t val, uint32_t len) "%s %02x:%x: sriov offset 0x%x val 0x%x len %d"
+
+# pcie.c
+pcie_cap_slot_write_config(const char *parent, const char *child, const char *pds, const char *old_pic, const char *new_pic, const char *old_aic, const char *new_aic, const char *old_power, const char *new_power) "%s > %s: pds: %s, pic: %s->%s, aic: %s->%s, power: %s->%s"
+
+# shpc.c
+shpc_slot_command(const char *parent, int pci_slot, const char *child, const char *old_pic, const char *new_pic, const char *old_aic, const char *new_aic, const char *old_state, const char *new_state) "%s[%d] > %s: pic: %s->%s, aic: %s->%s, state: %s->%s"