On Thu, 15 Jul 2021 18:05:06 -0500 Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > On Thu, Jul 15, 2021 at 11:39:54PM +0300, Ruben wrote: > > Thanks for the response, here's a link to the entire dmesg log: > > https://drive.google.com/file/d/1Uau0cgd2ymYGDXNr1mA9X_UdLoMH_Azn/view > > > > Some entries that might be of interest: > > ACPI tells us the host bridge windows are: > > acpi PNP0A08:00: host bridge window [mem 0x000a0000-0x000bffff window] (ignored) > acpi PNP0A08:00: host bridge window [mem 0x80000000-0xafffffff window] (ignored) > acpi PNP0A08:00: host bridge window [mem 0xc0000000-0xfebfffff window] (ignored) > acpi PNP0A08:00: host bridge window [mem 0x800000000-0xfffffffff window] (ignored) > > The 0xc0000000 window is about 1GB and is below 4GB. > The 0x800000000 window looks like 32GB. > > But "pci=nocrs" means we ignore these windows ... > > > pci_bus 0000:00: root bus resource [mem 0x00000000-0xffffffffff] > > and instead use this 1TB of address space, from which DRAM is > excluded. I think this is basically everything the CPU can address, > and I *think* it comes from this in setup_arch(): > > iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1; > > But you have 8 GPUs, each of which needs 128GB + 32MB + 16MB, so you > need 1TB + 384MB to map them all, and the CPU can't address that much. > > Since you're running this on qemu, I assume x86_phys_bits is telling > us about the capabilities of the CPU qemu is emulating. Maybe there's > a way to tell qemu to emulate a CPU with more address bits? "-cpu host" perhaps
