pci: reserve resources for pcie-pci-bridge to fix regressed hotplug on q35
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) 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  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.
Fixes: 3aa31d7d637 ("hw/pci: reserve IO and mem for pci express downstream ports with no devices attached")
Signed-off-by: Igor Mammedov email@example.com
Acked-by: Michael S. Tsirkin <firstname.lastname@example.org>
Tested-by: Laurent Vivier <email@example.com>
1 file changed