pci: hotplug handler reworks

Preparation for multi-stage hotplug handlers.

Signed-off-by David Hildenbrand <[email protected]>

---

 hw/ppc/spapr_pci.c | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

hw/ppc/spapr_pci.c +21 -12

index 58afa46204..64b8591023 100644
@@ -1370,18 +1370,9 @@ static int spapr_create_pci_child_dt(sPAPRPHBState *phb, PCIDevice *dev,
 /* Callback to be called during DRC release. */
 void spapr_phb_remove_pci_device_cb(DeviceState *dev)
 {
-    /* some version guests do not wait for completion of a device
-     * cleanup (generally done asynchronously by the kernel) before
-     * signaling to QEMU that the device is safe, but instead sleep
-     * for some 'safe' period of time. unfortunately on a busy host
-     * this sleep isn't guaranteed to be long enough, resulting in
-     * bad things like IRQ lines being left asserted during final
-     * device removal. to deal with this we call reset just prior
-     * to finalizing the device, which will put the device back into
-     * an 'idle' state, as the device cleanup code expects.
-     */
-    pci_device_reset(PCI_DEVICE(dev));
-    object_unparent(OBJECT(dev));
+    HotplugHandler *hotplug_ctrl = qdev_get_hotplug_handler(dev);
+
+    hotplug_handler_unplug(hotplug_ctrl, dev, &error_abort);
 }
 
 static sPAPRDRConnector *spapr_phb_get_pci_func_drc(sPAPRPHBState *phb,

@@ -1490,6 +1481,23 @@ out:
     }
 }
 
+static void spapr_pci_unplug(HotplugHandler *plug_handler,
+                             DeviceState *plugged_dev, Error **errp)
+{
+    /* some version guests do not wait for completion of a device
+     * cleanup (generally done asynchronously by the kernel) before
+     * signaling to QEMU that the device is safe, but instead sleep
+     * for some 'safe' period of time. unfortunately on a busy host
+     * this sleep isn't guaranteed to be long enough, resulting in
+     * bad things like IRQ lines being left asserted during final
+     * device removal. to deal with this we call reset just prior
+     * to finalizing the device, which will put the device back into
+     * an 'idle' state, as the device cleanup code expects.
+     */
+    pci_device_reset(PCI_DEVICE(plugged_dev));
+    object_unparent(OBJECT(plugged_dev));
+}
+
 static void spapr_pci_unplug_request(HotplugHandler *plug_handler,
                                      DeviceState *plugged_dev, Error **errp)
 {

@@ -1965,6 +1973,7 @@ static void spapr_phb_class_init(ObjectClass *klass, void *data)
     dc->user_creatable = true;
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
     hp->plug = spapr_pci_plug;
+    hp->unplug = spapr_pci_unplug;
     hp->unplug_request = spapr_pci_unplug_request;
 }
 

This series reworks some pci hotplug handlers (except for s390, that will require more work but is not required for now).

1. Route all unplug calls via the hotplug handler when called from the unplug_request handler. This will be required to get multi-stage hotplug handlers running, but also makes sense on its own (just like we already did for some CPU/memory hotplug handlers).

2. Introduce some pre_plug handlers where it makes sense already.

3. Call the plug/pre_plug handler also for coldplugged devices. Especially pcihp is special as it overwrites hotplug handlers.

This series will not yet factor out pre_plug/plug/unplug from pci device realize/unrealize functions, this will require more work but this series is also required first to get it running.

David Hildenbrand (7):
pcihp: perform check for bus capability in pre_plug handler
pcihp: overwrite hotplug handler recursively from the start
pcihp: route unplug via the hotplug handler pci/pcie: route unplug via the hotplug handler pci/shpc: move hotplug checks to preplug handler pci/shpc: route unplug via the hotplug handler
spapr_pci: route unplug via the hotplug handler

 hw/acpi/pcihp.c                 | 40 +++++++++++++++++++++++-----
 hw/acpi/piix4.c                 | 39 ++++++++++++++-------------
 hw/pci-bridge/pci_bridge_dev.c  | 23 +++++++++++++++-
 hw/pci-bridge/pcie_pci_bridge.c | 23 +++++++++++++++-
 hw/pci/pcie.c                   | 10 ++++++-
 hw/pci/pcie_port.c              |  1 +
 hw/pci/shpc.c                   | 47 ++++++++++++++++++---------------
 hw/ppc/spapr_pci.c              | 33 ++++++++++++++---------
 include/hw/acpi/pcihp.h         |  5 ++++
 include/hw/pci/pcie.h           |  2 ++
 include/hw/pci/shpc.h           |  4 +++
 11 files changed, 165 insertions(+), 62 deletions(-)

For now, the hotplug handler is not called for devices that are being cold plugged. The hotplug handler is setup when the machine initialization is fully done. Only bridges that were cold plugged are considered.

Set the hotplug handler for the root piix bus directly when realizing. Overwrite the hotplug handler of bridges when hotplugging/coldplugging them.

This will now make sure that the ACPI PCI hotplug handler is also called for cold-plugged devices (also on bridges) and for bridges that were hotplugged.

When trying to hotplug a device to a hotplugged bridge, we now correctly get the error message
"Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set"
Insted of going via the standard PCI hotplug handler.

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/acpi/pcihp.c | 10 ++++++++++
 hw/acpi/piix4.c | 16 +---------------
 2 files changed, 11 insertions(+), 15 deletions(-)

hw/acpi/pcihp.c +10 -0

index 5e7cef173c..647b5e8d82 100644
@@ -30,6 +30,7 @@
 #include "hw/hw.h"
 #include "hw/i386/pc.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bridge.h"
 #include "hw/acpi/acpi.h"
 #include "sysemu/sysemu.h"
 #include "exec/address-spaces.h"

@@ -236,6 +237,15 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
     int slot = PCI_SLOT(pdev->devfn);
     int bsel;
 
+    if (!s->legacy_piix && object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) {
+        PCIBus *sec = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
+
+        /* Overwrite the default hotplug handler with the ACPI PCI one. */
+        qbus_set_hotplug_handler(BUS(sec), DEVICE(hotplug_dev), &error_abort);
+        /* No need to do it recursively */
+        assert(QLIST_EMPTY(&sec->child));
+    }
+
     /* Don't send event when device is enabled during qemu machine creation:
      * it is present on boot, no hotplug event is necessary. We do send an
      * event when the device is disabled later. */

hw/acpi/piix4.c +1 -15

index 167afe2cea..e611778daf 100644
@@ -446,15 +446,6 @@ static void piix4_device_unplug_cb(HotplugHandler *hotplug_dev,
     }
 }
 
-static void piix4_update_bus_hotplug(PCIBus *pci_bus, void *opaque)
-{
-    PIIX4PMState *s = opaque;
-
-    /* pci_bus cannot outlive PIIX4PMState, because /machine keeps it alive
-     * and it's not hot-unpluggable */
-    qbus_set_hotplug_handler(BUS(pci_bus), DEVICE(s), &error_abort);
-}
-
 static void piix4_pm_machine_ready(Notifier *n, void *opaque)
 {
     PIIX4PMState *s = container_of(n, PIIX4PMState, machine_ready);

@@ -468,12 +459,6 @@ static void piix4_pm_machine_ready(Notifier *n, void *opaque)
     pci_conf[0x63] = 0x60;
     pci_conf[0x67] = (memory_region_present(io_as, 0x3f8) ? 0x08 : 0) |
         (memory_region_present(io_as, 0x2f8) ? 0x90 : 0);
-
-    if (s->use_acpi_pci_hotplug) {
-        pci_for_each_bus(pci_get_bus(d), piix4_update_bus_hotplug, s);
-    } else {
-        piix4_update_bus_hotplug(pci_get_bus(d), s);
-    }
 }
 
 static void piix4_pm_add_propeties(PIIX4PMState *s)

@@ -547,6 +532,7 @@ static void piix4_pm_realize(PCIDevice *dev, Error **errp)
 
     piix4_acpi_system_hot_add_init(pci_address_space_io(dev),
                                    pci_get_bus(dev), s);
+    qbus_set_hotplug_handler(BUS(pci_get_bus(dev)), DEVICE(s), &error_abort);
 
     piix4_pm_add_propeties(s);
 }

Perform the check in the pre_plug handler. In addition, we need the capability only if the device is actually hotplugged (and not created during machine initialization). This is a preparation for coldplugging devices via that hotplug handler.

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/acpi/pcihp.c         | 21 +++++++++++++++------
 hw/acpi/piix4.c         | 16 ++++++++++++++--
 include/hw/acpi/pcihp.h |  2 ++
 3 files changed, 31 insertions(+), 8 deletions(-)

hw/acpi/pcihp.c +15 -6

index 80d42e12ff..5e7cef173c 100644
@@ -217,17 +217,24 @@ void acpi_pcihp_reset(AcpiPciHpState *s)
     acpi_pcihp_update(s);
 }
 
-void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
-                               DeviceState *dev, Error **errp)
+void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
+                                   DeviceState *dev, Error **errp)
 {
-    PCIDevice *pdev = PCI_DEVICE(dev);
-    int slot = PCI_SLOT(pdev->devfn);
-    int bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
-    if (bsel < 0) {
+    /* Only hotplugged devices need the hotplug capability. */
+    if (dev->hotplugged &&
+        acpi_pcihp_get_bsel(pci_get_bus(PCI_DEVICE(dev))) < 0) {
         error_setg(errp, "Unsupported bus. Bus doesn't have property '"
                    ACPI_PCIHP_PROP_BSEL "' set");
         return;
     }
+}
+
+void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
+                               DeviceState *dev, Error **errp)
+{
+    PCIDevice *pdev = PCI_DEVICE(dev);
+    int slot = PCI_SLOT(pdev->devfn);
+    int bsel;
 
     /* Don't send event when device is enabled during qemu machine creation:
      * it is present on boot, no hotplug event is necessary. We do send an

@@ -236,6 +243,8 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
         return;
     }
 
+    bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
+    g_assert(bsel >= 0);
     s->acpi_pcihp_pci_status[bsel].up |= (1U << slot);
     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
 }

hw/acpi/piix4.c +14 -2

index e330f24c71..167afe2cea 100644
@@ -370,6 +370,18 @@ static void piix4_pm_powerdown_req(Notifier *n, void *opaque)
     acpi_pm1_evt_power_down(&s->ar);
 }
 
+static void piix4_device_pre_plug_cb(HotplugHandler *hotplug_dev,
+                                    DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+        acpi_pcihp_device_pre_plug_cb(hotplug_dev, dev, errp);
+    } else if (!object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
+               !object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        error_setg(errp, "acpi: device plug request for not supported device"
+                   " type: %s", object_get_typename(OBJECT(dev)));
+    }
+}
+
 static void piix4_device_plug_cb(HotplugHandler *hotplug_dev,
                                  DeviceState *dev, Error **errp)
 {

@@ -392,8 +404,7 @@ static void piix4_device_plug_cb(HotplugHandler *hotplug_dev,
             acpi_cpu_plug_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
         }
     } else {
-        error_setg(errp, "acpi: device plug request for not supported device"
-                   " type: %s", object_get_typename(OBJECT(dev)));
+        g_assert_not_reached();
     }
 }
 

@@ -702,6 +713,7 @@ static void piix4_pm_class_init(ObjectClass *klass, void *data)
      */
     dc->user_creatable = false;
     dc->hotpluggable = false;
+    hc->pre_plug = piix4_device_pre_plug_cb;
     hc->plug = piix4_device_plug_cb;
     hc->unplug_request = piix4_device_unplug_request_cb;
     hc->unplug = piix4_device_unplug_cb;

include/hw/acpi/pcihp.h +2 -0

index 8a65f99fc8..ce31625850 100644
@@ -56,6 +56,8 @@ typedef struct AcpiPciHpState {
 void acpi_pcihp_init(Object *owner, AcpiPciHpState *, PCIBus *root,
                      MemoryRegion *address_space_io, bool bridges_enabled);
 
+void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
+                                   DeviceState *dev, Error **errp);
 void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
                                DeviceState *dev, Error **errp);
 void acpi_pcihp_device_unplug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,

Preparation for multi-stage hotplug handlers.

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/acpi/pcihp.c         | 11 ++++++++++-
 hw/acpi/piix4.c         |  7 +++++--
 include/hw/acpi/pcihp.h |  3 +++
 3 files changed, 18 insertions(+), 3 deletions(-)

hw/acpi/pcihp.c +10 -1

index 647b5e8d82..062f3c9091 100644
@@ -154,6 +154,7 @@ static bool acpi_pcihp_pc_no_hotplug(AcpiPciHpState *s, PCIDevice *dev)
 
 static void acpi_pcihp_eject_slot(AcpiPciHpState *s, unsigned bsel, unsigned slots)
 {
+    HotplugHandler *hotplug_ctrl;
     BusChild *kid, *next;
     int slot = ctz32(slots);
     PCIBus *bus = acpi_pcihp_find_hotplug_bus(s, bsel);

@@ -171,7 +172,8 @@ static void acpi_pcihp_eject_slot(AcpiPciHpState *s, unsigned bsel, unsigned slo
         PCIDevice *dev = PCI_DEVICE(qdev);
         if (PCI_SLOT(dev->devfn) == slot) {
             if (!acpi_pcihp_pc_no_hotplug(s, dev)) {
-                object_unparent(OBJECT(qdev));
+                hotplug_ctrl = qdev_get_hotplug_handler(qdev);
+                hotplug_handler_unplug(hotplug_ctrl, qdev, &error_abort);
             }
         }
     }

@@ -261,6 +263,13 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
 
 void acpi_pcihp_device_unplug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
                                  DeviceState *dev, Error **errp)
+{
+    object_unparent(OBJECT(dev));
+}
+
+void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev,
+                                         AcpiPciHpState *s, DeviceState *dev,
+                                         Error **errp)
 {
     PCIDevice *pdev = PCI_DEVICE(dev);
     int slot = PCI_SLOT(pdev->devfn);

hw/acpi/piix4.c +5 -2

index e611778daf..ba5632becc 100644
@@ -418,8 +418,8 @@ static void piix4_device_unplug_request_cb(HotplugHandler *hotplug_dev,
         acpi_memory_unplug_request_cb(hotplug_dev, &s->acpi_memory_hotplug,
                                       dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
-        acpi_pcihp_device_unplug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev,
-                                    errp);
+        acpi_pcihp_device_unplug_request_cb(hotplug_dev, &s->acpi_pci_hotplug,
+                                            dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
                !s->cpu_hotplug_legacy) {
         acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev, errp);

@@ -437,6 +437,9 @@ static void piix4_device_unplug_cb(HotplugHandler *hotplug_dev,
     if (s->acpi_memory_hotplug.is_enabled &&
         object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
         acpi_memory_unplug_cb(&s->acpi_memory_hotplug, dev, errp);
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+        acpi_pcihp_device_unplug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev,
+                                    errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
                !s->cpu_hotplug_legacy) {
         acpi_cpu_unplug_cb(&s->cpuhp_state, dev, errp);

include/hw/acpi/pcihp.h +3 -0

index ce31625850..8bc4a4c01d 100644
@@ -62,6 +62,9 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
                                DeviceState *dev, Error **errp);
 void acpi_pcihp_device_unplug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
                                  DeviceState *dev, Error **errp);
+void acpi_pcihp_device_unplug_request_cb(HotplugHandler *hotplug_dev,
+                                         AcpiPciHpState *s, DeviceState *dev,
+                                         Error **errp);
 
 /* Called on reset */
 void acpi_pcihp_reset(AcpiPciHpState *s);

Preparation for multi-stage hotplug handlers.

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/pci/pcie.c         | 10 +++++++++-
 hw/pci/pcie_port.c    |  1 +
 include/hw/pci/pcie.h |  2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

hw/pci/pcie.c +9 -1

index 02a7bf3af5..744727dc0b 100644
@@ -364,11 +364,19 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
     }
 }
 
-static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
+void pcie_cap_slot_hot_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
+                                 Error **errp)
 {
     object_unparent(OBJECT(dev));
 }
 
+static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
+{
+    HotplugHandler *hotplug_ctrl = qdev_get_hotplug_handler(DEVICE(dev));
+
+    hotplug_handler_unplug(hotplug_ctrl, DEVICE(dev), &error_abort);
+}
+
 void pcie_cap_slot_hot_unplug_request_cb(HotplugHandler *hotplug_dev,
                                          DeviceState *dev, Error **errp)
 {

hw/pci/pcie_port.c +1 -0

index 13fe6c6945..6e993da603 100644
@@ -156,6 +156,7 @@ static void pcie_slot_class_init(ObjectClass *oc, void *data)
     dc->props = pcie_slot_props;
     hc->pre_plug = pcie_cap_slot_pre_plug_cb;
     hc->plug = pcie_cap_slot_hotplug_cb;
+    hc->unplug = pcie_cap_slot_hot_unplug_cb;
     hc->unplug_request = pcie_cap_slot_hot_unplug_request_cb;
 }
 

include/hw/pci/pcie.h +2 -0

index 001d230d7d..b6f05a0e43 100644
@@ -135,6 +135,8 @@ void pcie_cap_slot_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                                Error **errp);
 void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
                               Error **errp);
+void pcie_cap_slot_hot_unplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
+                                 Error **errp);
 void pcie_cap_slot_hot_unplug_request_cb(HotplugHandler *hotplug_dev,
                                          DeviceState *dev, Error **errp);
 #endif /* QEMU_PCIE_H */

Quoted 26 lines · David Hildenbrand

This series reworks some pci hotplug handlers (except for s390, that will require more work but is not required for now).

1. Route all unplug calls via the hotplug handler when called from the unplug_request handler. This will be required to get multi-stage hotplug handlers running, but also makes sense on its own (just like we already did for some CPU/memory hotplug handlers).

2. Introduce some pre_plug handlers where it makes sense already.

3. Call the plug/pre_plug handler also for coldplugged devices. Especially pcihp is special as it overwrites hotplug handlers.

This series will not yet factor out pre_plug/plug/unplug from pci device realize/unrealize functions, this will require more work but this series is also required first to get it running.

David Hildenbrand (7):
pcihp: perform check for bus capability in pre_plug handler
pcihp: overwrite hotplug handler recursively from the start
pcihp: route unplug via the hotplug handler pci/pcie: route unplug via the hotplug handler pci/shpc: move hotplug checks to preplug handler pci/shpc: route unplug via the hotplug handler
spapr_pci: route unplug via the hotplug handler

Quoted 13 lines

 hw/acpi/pcihp.c                 | 40 +++++++++++++++++++++++-----
 hw/acpi/piix4.c                 | 39 ++++++++++++++-------------
 hw/pci-bridge/pci_bridge_dev.c  | 23 +++++++++++++++-
 hw/pci-bridge/pcie_pci_bridge.c | 23 +++++++++++++++-
 hw/pci/pcie.c                   | 10 ++++++-
 hw/pci/pcie_port.c              |  1 +
 hw/pci/shpc.c                   | 47 ++++++++++++++++++---------------
 hw/ppc/spapr_pci.c              | 33 ++++++++++++++---------
 include/hw/acpi/pcihp.h         |  5 ++++
 include/hw/pci/pcie.h           |  2 ++
 include/hw/pci/shpc.h           |  4 +++
 11 files changed, 165 insertions(+), 62 deletions(-)

Did some more testing. Can somebody have a look/pick up? Thanks!

Quoted 41 lines · On Wed, 31 Oct 2018 18:31:30 +0100 David Hildenbrand <[email protected]> wrote:

Quoted 39 lines · David Hildenbrand

This series reworks some pci hotplug handlers (except for s390, that will require more work but is not required for now).

1. Route all unplug calls via the hotplug handler when called from the unplug_request handler. This will be required to get multi-stage hotplug handlers running, but also makes sense on its own (just like we already did for some CPU/memory hotplug handlers).

2. Introduce some pre_plug handlers where it makes sense already.

3. Call the plug/pre_plug handler also for coldplugged devices. Especially pcihp is special as it overwrites hotplug handlers.

This series will not yet factor out pre_plug/plug/unplug from pci device realize/unrealize functions, this will require more work but this series is also required first to get it running.

David Hildenbrand (7):
pcihp: perform check for bus capability in pre_plug handler
pcihp: overwrite hotplug handler recursively from the start
pcihp: route unplug via the hotplug handler pci/pcie: route unplug via the hotplug handler pci/shpc: move hotplug checks to preplug handler pci/shpc: route unplug via the hotplug handler
spapr_pci: route unplug via the hotplug handler

 hw/acpi/pcihp.c                 | 40 +++++++++++++++++++++++-----
 hw/acpi/piix4.c                 | 39 ++++++++++++++-------------
 hw/pci-bridge/pci_bridge_dev.c  | 23 +++++++++++++++-
 hw/pci-bridge/pcie_pci_bridge.c | 23 +++++++++++++++-
 hw/pci/pcie.c                   | 10 ++++++-
 hw/pci/pcie_port.c              |  1 +
 hw/pci/shpc.c                   | 47 ++++++++++++++++++---------------
 hw/ppc/spapr_pci.c              | 33 ++++++++++++++---------
 include/hw/acpi/pcihp.h         |  5 ++++
 include/hw/pci/pcie.h           |  2 ++
 include/hw/pci/shpc.h           |  4 +++
 11 files changed, 165 insertions(+), 62 deletions(-)

Quoted 1 line

Did some more testing. Can somebody have a look/pick up? Thanks!

Did a quick pass over series, patches overall looks good here is some other nits that apply to series:

* make more descriptive commit messages (important for history and for whoever comes later to read it)

* I don't really like a mix of style in callbacks naming
for ex: there is hotplug and then for unplug you add hot_unplug instead of hotunplug I'd prefer consistent approach in naming.
(either use underscores or drop them or maybe drop 'hot' part as it's not only for hotplug anymore)

Quoted 13 lines · On Wed, 24 Oct 2018 12:19:25 +0200 David Hildenbrand <[email protected]> wrote:

For now, the hotplug handler is not called for devices that are being cold plugged. The hotplug handler is setup when the machine initialization is fully done. Only bridges that were cold plugged are considered.

Set the hotplug handler for the root piix bus directly when realizing. Overwrite the hotplug handler of bridges when hotplugging/coldplugging them.

This will now make sure that the ACPI PCI hotplug handler is also called for cold-plugged devices (also on bridges) and for bridges that were hotplugged.

Quoted 4 lines

When trying to hotplug a device to a hotplugged bridge, we now correctly get the error message
"Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set"
Insted of going via the standard PCI hotplug handler.

Erroring out is probably not ok, since it can break existing setups where SHPC hotplugging to hotplugged bridge was working just fine before.

Marcel/Michael what's your take on this change in behaviour? CCing libvirt in case they are doing this stuff

Quoted 16 lines · Igor Mammedov

Quoted 13 lines · On Wed, 24 Oct 2018 12:19:25 +0200 David Hildenbrand <[email protected]> wrote:

For now, the hotplug handler is not called for devices that are being cold plugged. The hotplug handler is setup when the machine initialization is fully done. Only bridges that were cold plugged are considered.

Set the hotplug handler for the root piix bus directly when realizing. Overwrite the hotplug handler of bridges when hotplugging/coldplugging them.

This will now make sure that the ACPI PCI hotplug handler is also called for cold-plugged devices (also on bridges) and for bridges that were hotplugged.

Quoted 6 lines

Quoted 4 lines

When trying to hotplug a device to a hotplugged bridge, we now correctly get the error message
"Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set"
Insted of going via the standard PCI hotplug handler.

Erroring out is probably not ok, since it can break existing setups where SHPC hotplugging to hotplugged bridge was working just fine before.

The question is if it actually was supposed (and eventually did) work.

If this was the expected behavior (mixing hotplug types), then the necessary change to this patch would boil down to checking if the bridge it hot or coldplugged.

Quoted 4 lines

Marcel/Michael what's your take on this change in behaviour? CCing libvirt in case they are doing this stuff

Indeed, it would be nice to know if this was actually supposed to work like this (coldplugged bridges using ACPI hotplug and hotplugged bridges using SHPC hotplug).

Quoted 24 lines · On Fri, 2 Nov 2018 12:43:10 +0100 David Hildenbrand <[email protected]> wrote:

Quoted 22 lines · Igor Mammedov

Quoted 9 lines · On Wed, 24 Oct 2018 12:19:25 +0200 David Hildenbrand <[email protected]> wrote:

For now, the hotplug handler is not called for devices that are being cold plugged. The hotplug handler is setup when the machine initialization is fully done. Only bridges that were cold plugged are considered.

Set the hotplug handler for the root piix bus directly when realizing. Overwrite the hotplug handler of bridges when hotplugging/coldplugging them.

Quoted 8 lines

This will now make sure that the ACPI PCI hotplug handler is also called for cold-plugged devices (also on bridges) and for bridges that were hotplugged.

When trying to hotplug a device to a hotplugged bridge, we now correctly get the error message
"Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set"
Insted of going via the standard PCI hotplug handler.

Erroring out is probably not ok, since it can break existing setups where SHPC hotplugging to hotplugged bridge was working just fine before.

Quoted 1 line

The question is if it actually was supposed (and eventually did) work.

I think it works now, it's QEMU 'ACPI hotplug hack' (which exists for the sake of Windows) limitation. We weren't able to dynamically add ACPI description for hotplugged bridge, so it was using native hotplug. Now theoretically we can load tables dynamically but that, would add maintenance nightmare (versioned tables) and would be harder to debug. I'd rather not go that direction and keep current limited version, suggesting users to use native hotplug if guest is capable.

Quoted 24 lines · On Fri, 2 Nov 2018 12:43:10 +0100 David Hildenbrand <[email protected]> wrote:

Quoted 22 lines · Igor Mammedov

Quoted 9 lines · On Wed, 24 Oct 2018 12:19:25 +0200 David Hildenbrand <[email protected]> wrote:

For now, the hotplug handler is not called for devices that are being cold plugged. The hotplug handler is setup when the machine initialization is fully done. Only bridges that were cold plugged are considered.

Set the hotplug handler for the root piix bus directly when realizing. Overwrite the hotplug handler of bridges when hotplugging/coldplugging them.

Quoted 8 lines

This will now make sure that the ACPI PCI hotplug handler is also called for cold-plugged devices (also on bridges) and for bridges that were hotplugged.

When trying to hotplug a device to a hotplugged bridge, we now correctly get the error message
"Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set"
Insted of going via the standard PCI hotplug handler.

Erroring out is probably not ok, since it can break existing setups where SHPC hotplugging to hotplugged bridge was working just fine before.

Quoted 1 line

The question is if it actually was supposed (and eventually did) work.

I think it works now, it's QEMU 'ACPI hotplug hack' (which exists for the sake of Windows) limitation. We weren't able to dynamically add ACPI description for hotplugged bridge, so it was using native hotplug. Now theoretically we can load tables dynamically but that, would add maintenance nightmare (versioned tables) and would be harder to debug. I'd rather not go that direction and keep current limited version, suggesting users to use native hotplug if guest is capable.

Quoted 14 lines

If this was the expected behavior (mixing hotplug types), then the necessary change to this patch would boil down to checking if the bridge it hot or coldplugged.

Quoted 4 lines

Marcel/Michael what's your take on this change in behaviour? CCing libvirt in case they are doing this stuff

Indeed, it would be nice to know if this was actually supposed to work like this (coldplugged bridges using ACPI hotplug and hotplugged bridges using SHPC hotplug).

Move the checks to the pre_plug handler. I don't see a reason to check for the PCI slot when unplugging.

Signed-off-by David Hildenbrand <[email protected]>

---
 hw/pci-bridge/pci_bridge_dev.c  | 11 ++++++++--
 hw/pci-bridge/pcie_pci_bridge.c | 11 ++++++++--
 hw/pci/shpc.c                   | 36 ++++++++++++++-------------------
 include/hw/pci/shpc.h           |  2 ++
 4 files changed, 35 insertions(+), 25 deletions(-)

hw/pci-bridge/pci_bridge_dev.c +9 -2

index 97a8e8b6a4..2362dcbc64 100644
@@ -206,8 +206,8 @@ static const VMStateDescription pci_bridge_dev_vmstate = {
     }
 };
 
-static void pci_bridge_dev_hotplug_cb(HotplugHandler *hotplug_dev,
-                                      DeviceState *dev, Error **errp)
+static void pci_bridge_dev_pre_plug_cb(HotplugHandler *hotplug_dev,
+                                       DeviceState *dev, Error **errp)
 {
     PCIDevice *pci_hotplug_dev = PCI_DEVICE(hotplug_dev);
 

@@ -216,6 +216,12 @@ static void pci_bridge_dev_hotplug_cb(HotplugHandler *hotplug_dev,
                    "this %s", TYPE_PCI_BRIDGE_DEV);
         return;
     }
+    shpc_device_pre_plug_cb(hotplug_dev, dev, errp);
+}
+
+static void pci_bridge_dev_hotplug_cb(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
     shpc_device_hotplug_cb(hotplug_dev, dev, errp);
 }
 

@@ -251,6 +257,7 @@ static void pci_bridge_dev_class_init(ObjectClass *klass, void *data)
     dc->props = pci_bridge_dev_properties;
     dc->vmsd = &pci_bridge_dev_vmstate;
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    hc->pre_plug = pci_bridge_dev_pre_plug_cb;
     hc->plug = pci_bridge_dev_hotplug_cb;
     hc->unplug_request = pci_bridge_dev_hot_unplug_request_cb;
 }

hw/pci-bridge/pcie_pci_bridge.c +9 -2

index 04cf5a6a92..cde8af0a4e 100644
@@ -137,8 +137,8 @@ static const VMStateDescription pcie_pci_bridge_dev_vmstate = {
         }
 };
 
-static void pcie_pci_bridge_hotplug_cb(HotplugHandler *hotplug_dev,
-                                      DeviceState *dev, Error **errp)
+static void pcie_pci_bridge_pre_plug_cb(HotplugHandler *hotplug_dev,
+                                        DeviceState *dev, Error **errp)
 {
     PCIDevice *pci_hotplug_dev = PCI_DEVICE(hotplug_dev);
 

@@ -147,6 +147,12 @@ static void pcie_pci_bridge_hotplug_cb(HotplugHandler *hotplug_dev,
                    "this %s", TYPE_PCIE_PCI_BRIDGE_DEV);
         return;
     }
+    shpc_device_pre_plug_cb(hotplug_dev, dev, errp);
+}
+
+static void pcie_pci_bridge_hotplug_cb(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
     shpc_device_hotplug_cb(hotplug_dev, dev, errp);
 }
 

@@ -180,6 +186,7 @@ static void pcie_pci_bridge_class_init(ObjectClass *klass, void *data)
     dc->props = pcie_pci_bridge_dev_properties;
     dc->reset = &pcie_pci_bridge_reset;
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    hc->pre_plug = pcie_pci_bridge_pre_plug_cb;
     hc->plug = pcie_pci_bridge_hotplug_cb;
     hc->unplug_request = pcie_pci_bridge_hot_unplug_request_cb;
 }

hw/pci/shpc.c +8 -4

index a8462d48bb..1caf4a7ee9 100644
@@ -482,13 +482,21 @@ static const MemoryRegionOps shpc_mmio_ops = {
         .max_access_size = 4,
     },
 };
-static void shpc_device_hotplug_common(PCIDevice *affected_dev, int *slot,
-                                       SHPCDevice *shpc, Error **errp)
+
+static inline int shpc_device_get_slot(PCIDevice *dev)
+{
+    return SHPC_PCI_TO_IDX(dev->devfn);
+}
+
+void shpc_device_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
+                             Error **errp)
 {
-    int pci_slot = PCI_SLOT(affected_dev->devfn);
-    *slot = SHPC_PCI_TO_IDX(pci_slot);