acpi: pcihp: pcie: set power on cap on parent slot

on creation a PCIDevice has power turned on at the end of pci_qdev_realize()
however later on if PCIe slot isn't populated with any children
it's power is turned off. It's fine if native hotplug is used
as plug callback will power slot on among other things.
However when ACPI hotplug is enabled it replaces native PCIe plug
callbacks with ACPI specific ones (acpi_pcihp_device_*plug_cb) and
as result slot stays powered off. It works fine as ACPI hotplug
on guest side takes care of enumerating/initializing hotplugged
device. But when later guest is migrated, call chain introduced by]
commit d5daff7d312 (pcie: implement slot power control for pcie root ports)

   pcie_cap_slot_post_load()
       -> pcie_cap_update_power()
           -> pcie_set_power_device()
               -> pci_set_power()
                   -> pci_update_mappings()

will disable earlier initialized BARs for the hotplugged device
in powered off slot due to commit 23786d13441 (pci: implement power state)
which disables BARs if power is off.

Fix it by setting PCI_EXP_SLTCTL_PCC to PCI_EXP_SLTCTL_PWR_ON
on slot (root port/downstream port) at the time a device
hotplugged into it. As result PCI_EXP_SLTCTL_PWR_ON is migrated
to target and above call chain keeps device plugged into it
powered on.

Fixes: d5daff7d312 ("pcie: implement slot power control for pcie root ports")
Fixes: 23786d13441 ("pci: implement power state")
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2053584
Suggested-by: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20220301151200.3507298-3-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index 6befd23e164f6e0a69c44c462c341c350afdd132..6351bd3424d894651ba0d1bad804ea42d0950cb4 100644 (file)
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -32,6 +32,7 @@
 #include "hw/pci/pci_bridge.h"
 #include "hw/pci/pci_host.h"
 #include "hw/pci/pcie_port.h"
+#include "hw/pci-bridge/xio3130_downstream.h"
 #include "hw/i386/acpi-build.h"
 #include "hw/acpi/acpi.h"
 #include "hw/pci/pci_bus.h"
@@ -336,6 +337,8 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
 {
     PCIDevice *pdev = PCI_DEVICE(dev);
     int slot = PCI_SLOT(pdev->devfn);
+    PCIDevice *bridge;
+    PCIBus *bus;
     int bsel;
 
     /* Don't send event when device is enabled during qemu machine creation:
@@ -365,7 +368,14 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
         return;
     }
 
-    bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
+    bus = pci_get_bus(pdev);
+    bridge = pci_bridge_get_device(bus);
+    if (object_dynamic_cast(OBJECT(bridge), TYPE_PCIE_ROOT_PORT) ||
+        object_dynamic_cast(OBJECT(bridge), TYPE_XIO3130_DOWNSTREAM)) {
+        pcie_cap_slot_enable_power(bridge);
+    }
+
+    bsel = acpi_pcihp_get_bsel(bus);
     g_assert(bsel >= 0);
     s->acpi_pcihp_pci_status[bsel].up |= (1U << slot);
     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 3c44204cf31b25ee0ceaed0357567a4edc70227f..67a5d67372e48ba2194dd382fffc186bf043df6f 100644 (file)
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -366,6 +366,17 @@ static void hotplug_event_clear(PCIDevice *dev)
     }
 }
 
+void pcie_cap_slot_enable_power(PCIDevice *dev)
+{
+    uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
+    uint32_t sltcap = pci_get_long(exp_cap + PCI_EXP_SLTCAP);
+
+    if (sltcap & PCI_EXP_SLTCAP_PCP) {
+        pci_set_word_by_mask(exp_cap + PCI_EXP_SLTCTL,
+                             PCI_EXP_SLTCTL_PCC, PCI_EXP_SLTCTL_PWR_ON);
+    }
+}
+
 static void pcie_set_power_device(PCIBus *bus, PCIDevice *dev, void *opaque)
 {
     bool *power = opaque;

diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
index 168950a83b776cb17e0d595bf476aa66d2f5c2e7..798a262a0a6cbd919781bc5fd8000e5e0abec76a 100644 (file)
--- a/include/hw/pci/pcie.h
+++ b/include/hw/pci/pcie.h
@@ -118,6 +118,7 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
                                 uint32_t addr, uint32_t val, int len);
 int pcie_cap_slot_post_load(void *opaque, int version_id);
 void pcie_cap_slot_push_attention_button(PCIDevice *dev);
+void pcie_cap_slot_enable_power(PCIDevice *dev);
 
 void pcie_cap_root_init(PCIDevice *dev);
 void pcie_cap_root_reset(PCIDevice *dev);