[Public] > From: Gerd Hoffmann <kra...@redhat.com> > Sent: Thursday, January 2, 2025 8:52 > On Tue, Dec 31, 2024 at 09:24:09PM +0000, Li, Yunxiang (Teddy) via SeaBIOS > wrote: > > [Public] > > > > Hi all, > > > > I've ran into an issue where the 64 bit address window allocated for one of > > the > PCI-e host devices overlaps with a BIOS reserved range of > fd00000000-ffffffffff, > making that device unusable. > > > > 4000000000-7bfffffffff : PCI Bus 0000:00 > > 4000000000-bfffffffff : PCI Bus 0000:0c > > 4000000000-7fffffffff : 0000:0c:00.0 > > 8000000000-80001fffff : 0000:0c:00.0 > > c000000000-13fffffffff : PCI Bus 0000:0b > > c000000000-ffffffffff : 0000:0b:00.0 > > fd00000000-ffffffffff : Reserved > > 10000000000-100001fffff : 0000:0b:00.0 > > > > 8000000000-7ffffffffff : PCI Bus 0000:00 > > 8000000000-ffffffffff : PCI Bus 0000:0c > > 8000000000-bfffffffff : 0000:0c:00.0 > > c000000000-c0001fffff : 0000:0c:00.0 > > fd00000000-ffffffffff : Reserved > > 10000000000-17fffffffff : PCI Bus 0000:0b > > 10000000000-13fffffffff : 0000:0b:00.0 > > 14000000000-140001fffff : 0000:0b:00.0 > > > > I found that increasing the system ram of the VM to ~256G changes the > > address window and avoids the issue, and with some digging I think I > > found the root cause > > > > To begin, QEMU set this address range to be reserved here, and this is > > passed to > Seabios via "etc/e820". > > https://gitlab.com/qemu-project/qemu/-/blob/master/hw/i386/pc.c#L865 > > Separately QEMU pass to Seabios "etc/reserved-memory-end" here which > > is derived from machine->device_memory > > https://gitlab.com/qemu-project/qemu/-/blob/master/hw/i386/pc.c#L1007 > > > > In Seabios, "etc/e820" is consumed here, which sets RamSizeOver4G only using > the E820_RAM entries, ignoring any E820_RESERVED entries. > > https://gitlab.com/qemu-project/seabios/-/blob/master/src/fw/paravirt. > > c#L782 Later "etc/reserved-memory-end" and RamSizeOver4G is used to > > determine the start of the PCI-e address window. > > https://gitlab.com/qemu-project/seabios/-/blob/master/src/fw/pciinit.c > > #L1138 > > > > I think either QEMU should set etc/reserved-memory-end to be after both > physical memory and the reserved ranges, or Seabios need to check both etc/820 > and etc/reserved-memory-end. But I'm not sure which would be the correct move > and indeed how to patch them. > > commit 1e1da7a96300 ("check for e820 conflict") should fix that. > > take care, > Gerd
Thanks! That indeed fixes the issue, I was using 1.16.2 and 1.16.3 fixes it. I was using a weird version of QEMU but I should have tried updating Seabios itself first, d'oh! Regards, Teddy _______________________________________________ SeaBIOS mailing list -- seabios@seabios.org To unsubscribe send an email to seabios-le...@seabios.org
