On Tue, Apr 18, 2023 at 10:50 AM Igor Mammedov <imammedo@xxxxxxxxxx> wrote: > > When using ACPI PCI hotplug, hotplugging a device with > large BARs may fail if bridge windows programmed by > firmware are not large enough. > > Reproducer: > $ qemu-kvm -monitor stdio -M q35 -m 4G \ > -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=on \ > -device id=rp1,pcie-root-port,bus=pcie.0,chassis=4 \ > disk_image > > wait till linux guest boots, then hotplug device > (qemu) device_add qxl,bus=rp1 > > hotplug on guest side fails with: > pci 0000:01:00.0: [1b36:0100] type 00 class 0x038000 > pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x03ffffff] > pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x03ffffff] > pci 0000:01:00.0: reg 0x18: [mem 0x00000000-0x00001fff] > pci 0000:01:00.0: reg 0x1c: [io 0x0000-0x001f] > pci 0000:01:00.0: BAR 0: no space for [mem size 0x04000000] > pci 0000:01:00.0: BAR 0: failed to assign [mem size 0x04000000] > pci 0000:01:00.0: BAR 1: no space for [mem size 0x04000000] > pci 0000:01:00.0: BAR 1: failed to assign [mem size 0x04000000] > pci 0000:01:00.0: BAR 2: assigned [mem 0xfe800000-0xfe801fff] > pci 0000:01:00.0: BAR 3: assigned [io 0x1000-0x101f] > qxl 0000:01:00.0: enabling device (0000 -> 0003) > Unable to create vram_mapping > qxl: probe of 0000:01:00.0 failed with error -12 > > However when using native PCIe hotplug > '-global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' > it works fine, since kernel attempts to reassign unused resources. > Use the same machinery as native PCIe hotplug to (re)assign resources. > > Signed-off-by: Igor Mammedov <imammedo@xxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> or please let me know if you want me to pick this up. > --- > tested in QEMU with Q35 machine on PCIE root port and also > with nested conventional bridge attached to root port. > --- > drivers/pci/hotplug/acpiphp_glue.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c > index 5b1f271c6034..9aebde28a92f 100644 > --- a/drivers/pci/hotplug/acpiphp_glue.c > +++ b/drivers/pci/hotplug/acpiphp_glue.c > @@ -517,7 +517,7 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge) > } > } > } > - __pci_bus_assign_resources(bus, &add_list, NULL); > + pci_assign_unassigned_bridge_resources(bus->self); > } > > acpiphp_sanitize_bus(bus); > -- > 2.39.1 >
