qemu-kvm/kvm-acpi-pcihp-pcie-set-power-on-cap-on-parent-slot.patch

From c9ceb175667cdeead59384a97a812367ae19c570 Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Wed, 23 Mar 2022 13:21:40 -0400
Subject: [PATCH 06/18] acpi: pcihp: pcie: set power on cap on parent slot

RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 134: pci: expose TYPE_XIO3130_DOWNSTREAM name
RH-Commit: [2/2] d883872647a6e90ec573140b2c171f3f53b600ab (jmaloy/qemu-kvm)
RH-Bugzilla: 2062610
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>

BZ: https://bugzilla.redhat.com/2062610
UPSTREAM: merged
BREW: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=44038138

commit 6b0969f1ec825984cd74619f0730be421b0c46fb
Author: Igor Mammedov <imammedo@redhat.com>
Date:   Tue Mar 1 10:11:59 2022 -0500

    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>

(cherry picked from commit 6b0969f1ec825984cd74619f0730be421b0c46fb)
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 hw/acpi/pcihp.c       | 12 +++++++++++-
 hw/pci/pcie.c         | 11 +++++++++++
 include/hw/pci/pcie.h |  1 +
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index a5e182dd3a..be0e846b34 100644
--- 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"
@@ -341,6 +342,8 @@ 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:
@@ -370,7 +373,14 @@ 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 d7d73a31e4..996f0e24fe 100644
--- 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 6063bee0ec..c27368d077 100644
--- a/include/hw/pci/pcie.h
+++ b/include/hw/pci/pcie.h
@@ -112,6 +112,7 @@ 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);
-- 
2.27.0