From 4a31485efad9db7feed56f483e123f0b58c38b2f Mon Sep 17 00:00:00 2001 From: Igor Mammedov 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 Acked-by: Michael S. Tsirkin Message-Id: <20211129114812.231849-2-imammedo@redhat.com> Signed-off-by: Gerd Hoffmann --- 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