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

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From c655f89956c69dc4bb3c3c74515c6c04bd0195bb Mon Sep 17 00:00:00 2001
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From: Igor Mammedov <imammedo@redhat.com>
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Date: Tue, 1 Mar 2022 10:11:59 -0500
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Subject: [PATCH 6/6] acpi: pcihp: pcie: set power on cap on parent slot
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RH-Author: Igor Mammedov <imammedo@redhat.com>
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RH-MergeRequest: 125: RHEL-8.6 Fix broken PCIe device after migration
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RH-Commit: [2/2] effbd75b9d495c88dd4d910b547154849fb1e821
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RH-Bugzilla: 2054597
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RH-Acked-by: Jon Maloy <jmaloy@redhat.com>
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RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>
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RH-Acked-by: MST <None>
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on creation a PCIDevice has power turned on at the end of pci_qdev_realize()
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however later on if PCIe slot isn't populated with any children
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it's power is turned off. It's fine if native hotplug is used
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as plug callback will power slot on among other things.
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However when ACPI hotplug is enabled it replaces native PCIe plug
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callbacks with ACPI specific ones (acpi_pcihp_device_*plug_cb) and
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as result slot stays powered off. It works fine as ACPI hotplug
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on guest side takes care of enumerating/initializing hotplugged
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device. But when later guest is migrated, call chain introduced by]
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commit d5daff7d312 (pcie: implement slot power control for pcie root ports)
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   pcie_cap_slot_post_load()
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       -> pcie_cap_update_power()
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           -> pcie_set_power_device()
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               -> pci_set_power()
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                   -> pci_update_mappings()
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will disable earlier initialized BARs for the hotplugged device
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in powered off slot due to commit 23786d13441 (pci: implement power state)
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which disables BARs if power is off.
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Fix it by setting PCI_EXP_SLTCTL_PCC to PCI_EXP_SLTCTL_PWR_ON
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on slot (root port/downstream port) at the time a device
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hotplugged into it. As result PCI_EXP_SLTCTL_PWR_ON is migrated
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to target and above call chain keeps device plugged into it
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powered on.
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Fixes: d5daff7d312 ("pcie: implement slot power control for pcie root ports")
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Fixes: 23786d13441 ("pci: implement power state")
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Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2053584
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Suggested-by: "Michael S. Tsirkin" <mst@redhat.com>
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Signed-off-by: Igor Mammedov <imammedo@redhat.com>
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Message-Id: <20220301151200.3507298-3-imammedo@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit 6b0969f1ec825984cd74619f0730be421b0c46fb)
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Signed-off-by: Igor Mammedov <imammedo@redhat.com>
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---
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 hw/acpi/pcihp.c       | 12 +++++++++++-
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 hw/pci/pcie.c         | 11 +++++++++++
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 include/hw/pci/pcie.h |  1 +
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 3 files changed, 23 insertions(+), 1 deletion(-)
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diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
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index a5e182dd3a..be0e846b34 100644
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--- a/hw/acpi/pcihp.c
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+++ b/hw/acpi/pcihp.c
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@@ -32,6 +32,7 @@
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 #include "hw/pci/pci_bridge.h"
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 #include "hw/pci/pci_host.h"
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 #include "hw/pci/pcie_port.h"
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+#include "hw/pci-bridge/xio3130_downstream.h"
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 #include "hw/i386/acpi-build.h"
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 #include "hw/acpi/acpi.h"
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 #include "hw/pci/pci_bus.h"
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@@ -341,6 +342,8 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
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 {
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     PCIDevice *pdev = PCI_DEVICE(dev);
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     int slot = PCI_SLOT(pdev->devfn);
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+    PCIDevice *bridge;
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+    PCIBus *bus;
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     int bsel;
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     /* Don't send event when device is enabled during qemu machine creation:
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@@ -370,7 +373,14 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
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         return;
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     }
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-    bsel = acpi_pcihp_get_bsel(pci_get_bus(pdev));
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+    bus = pci_get_bus(pdev);
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+    bridge = pci_bridge_get_device(bus);
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+    if (object_dynamic_cast(OBJECT(bridge), TYPE_PCIE_ROOT_PORT) ||
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+        object_dynamic_cast(OBJECT(bridge), TYPE_XIO3130_DOWNSTREAM)) {
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+        pcie_cap_slot_enable_power(bridge);
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+    }
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+
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+    bsel = acpi_pcihp_get_bsel(bus);
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     g_assert(bsel >= 0);
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     s->acpi_pcihp_pci_status[bsel].up |= (1U << slot);
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     acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
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diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
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index d7d73a31e4..996f0e24fe 100644
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--- a/hw/pci/pcie.c
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+++ b/hw/pci/pcie.c
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@@ -366,6 +366,17 @@ static void hotplug_event_clear(PCIDevice *dev)
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     }
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 }
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+void pcie_cap_slot_enable_power(PCIDevice *dev)
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+{
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+    uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
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+    uint32_t sltcap = pci_get_long(exp_cap + PCI_EXP_SLTCAP);
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+
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+    if (sltcap & PCI_EXP_SLTCAP_PCP) {
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+        pci_set_word_by_mask(exp_cap + PCI_EXP_SLTCTL,
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+                             PCI_EXP_SLTCTL_PCC, PCI_EXP_SLTCTL_PWR_ON);
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+    }
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+}
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+
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 static void pcie_set_power_device(PCIBus *bus, PCIDevice *dev, void *opaque)
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 {
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     bool *power = opaque;
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diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
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index 6063bee0ec..c27368d077 100644
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--- a/include/hw/pci/pcie.h
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+++ b/include/hw/pci/pcie.h
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@@ -112,6 +112,7 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
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                                 uint32_t addr, uint32_t val, int len);
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 int pcie_cap_slot_post_load(void *opaque, int version_id);
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 void pcie_cap_slot_push_attention_button(PCIDevice *dev);
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+void pcie_cap_slot_enable_power(PCIDevice *dev);
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 void pcie_cap_root_init(PCIDevice *dev);
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 void pcie_cap_root_reset(PCIDevice *dev);
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-- 
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2.27.0
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