From 4a31485efad9db7feed56f483e123f0b58c38b2f Mon Sep 17 00:00:00 2001
From: Igor Mammedov <imammedo@redhat.com>
Date: Mon, 29 Nov 2021 06:48:11 -0500
Subject: pci: reserve resources for pcie-pci-bridge to fix regressed hotplug
on q35
RH-Bugzilla: 2001921
If QEMU is started with unpopulated pcie-pci-bridge with ACPI PCI
hotplug enabled (default since QEMU-6.1), hotplugging a PCI device
into one of the bridge slots fails due to lack of resources.
once linux guest is booted (test used Fedora 34), hotplug NIC from
QEMU monitor:
(qemu) device_add rtl8139,bus=pcie-pci-bridge-0,addr=0x2
guest fails hotplug with:
pci 0000:01:02.0: [10ec:8139] type 00 class 0x020000
pci 0000:01:02.0: reg 0x10: [io 0x0000-0x00ff]
pci 0000:01:02.0: reg 0x14: [mem 0x00000000-0x000000ff]
pci 0000:01:02.0: reg 0x30: [mem 0x00000000-0x0003ffff pref]
pci 0000:01:02.0: BAR 6: no space for [mem size 0x00040000 pref]
pci 0000:01:02.0: BAR 6: failed to assign [mem size 0x00040000 pref]
pci 0000:01:02.0: BAR 0: no space for [io size 0x0100]
pci 0000:01:02.0: BAR 0: failed to assign [io size 0x0100]
pci 0000:01:02.0: BAR 1: no space for [mem size 0x00000100]
pci 0000:01:02.0: BAR 1: failed to assign [mem size 0x00000100]
8139cp: 8139cp: 10/100 PCI Ethernet driver v1.3 (Mar 22, 2004)
PCI Interrupt Link [GSIG] enabled at IRQ 22
8139cp 0000:01:02.0: no MMIO resource
8139cp: probe of 0000:01:02.0 failed with error -5
Reason for this is that commit [1] didn't take into account
pcie-pci-bridge, marking bridge as non hotpluggable instead of
handling it as possibly SHPC capable bridge.
Fix issue by checking if pcie-pci-bridge is SHPC capable and
if it is mark it as hotpluggable.
Fixes regression in QEMU-6.1 and later, since it was switched
to ACPI based PCI hotplug on Q35 by default at that time.
[1]
Fixes: 3aa31d7d637 ("hw/pci: reserve IO and mem for pci express downstream ports with no devices attached")
Signed-off-by: Igor Mammedov imammedo@redhat.com
CC: mapfelba@redhat.com
CC: kraxel@redhat.com
CC: mst@redhat.com
CC: lvivier@redhat.com
CC: jusual@redhat.com
Tested-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20211129114812.231849-2-imammedo@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
src/fw/pciinit.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 3c99d51..badf13d 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -808,6 +808,10 @@ static hotplug_type_t pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
pcie_cap + PCI_EXP_FLAGS);
u8 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
(__builtin_ffs(PCI_EXP_FLAGS_TYPE) - 1));
+
+ if (port_type == PCI_EXP_TYPE_PCI_BRIDGE)
+ goto check_shpc;
+
u8 downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
(port_type == PCI_EXP_TYPE_ROOT_PORT);
/*
@@ -825,6 +829,7 @@ static hotplug_type_t pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
HOTPLUG_PCIE : HOTPLUG_NO_SUPPORTED;
}
+check_shpc:
shpc_cap = pci_find_capability(bus->bus_dev->bdf, PCI_CAP_ID_SHPC, 0);
return !!shpc_cap ? HOTPLUG_SHPC : HOTPLUG_NO_SUPPORTED;
}
--
2.27.0