On Mon, Apr 24, 2023 at 09:15:57PM +0200, Igor Mammedov 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) Ugh, I just noticed that we turned on PCI_COMMAND_MEMORY even though BARs 0 and 1 haven't been assigned. How did that happen? It looks like pci_enable_resources() checks for that, but there must be a hole somewhere. > Unable to create vram_mapping > qxl: probe of 0000:01:00.0 failed with error -12
