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[Bug 1851972] Re: pc-q35-4.1 and AMD Navi 5700/XT incompatible
From: |
Joey Adams |
Subject: |
[Bug 1851972] Re: pc-q35-4.1 and AMD Navi 5700/XT incompatible |
Date: |
Mon, 13 Jan 2020 02:25:08 -0000 |
Commit 11bc4a13 (Nov 13, 2019, merged after v4.2.0-rc5) moved the
kernel-irqchip parameter to -accel, but I think the default was
inadvertently changed to off. The documentation was changed to say the
default is on, but the code change seems to have done the opposite.
I found this when I tested my Windows Server 2016 VMs with the last qemu
from git. Windows boots and runs very slowly unless I add either
<ioapic driver='kvm'/> (kernel_irqchip=on) or <timer name="hypervclock"
present="yes"/> to the libvirt config. Using the qemu installed with
Ubuntu 19.10 (version 4.0.0), I can reproduce the slowness by explicitly
adding kernel_irqchip=off.
Details:
- Host CPU: Ryzen 3950X (16 core, 32 thread)
- Host RAM: 64 GiB
- Host OS: Ubuntu 19.10 64-bit, kernel version 5.5.0-rc4 (commit 738d2902773e +
ACS override patch)
- Guest CPU: host-passthrough, 16 vcpus (8 cores, 2 threads, topoext).
- Guest RAM: 12 GiB
- Guest machine type: pc-i440fx-4.0 (BIOS boot)
- Guest OS: Windows Server 2016, build 1607
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https://bugs.launchpad.net/bugs/1851972
Title:
pc-q35-4.1 and AMD Navi 5700/XT incompatible
Status in QEMU:
New
Bug description:
Hello,
I am not sure if this qualifies as a "bug"; it is be more of an
unknown issue with default settings. However, since the default value
of q35 default_kernel_irqchip_split was changed seemingly due to
similar user feedback, I thought this was important to share..
AMD Navi 5700/XT vfio-pci passthrough seems incompatible with
one/multiple settings in pc-q35-3.1 and higher. The workaround for me
is that pc-q35-3.0 still works fine passing through the GPU and
official drivers can load/install fine.
The default/generic GPU drivers in a Fedora 30 or Windows 1903 guest
do work; the monitor displays the desktop in a 800x600 resolution and
things are rendered fine.. so the basic functionality of the card
seems fine with pc-q35-4.1.
But attempting to use the official open source AMD driver with the
card resulted in a hung kernel for the Fedora 30 guest.. and a BSOD on
the Windows 1903 guest immediately during driver install.
I do not see any errors in Qemu command output.. did not investigate
other logs or KVM etc, because I am not sure what to look for or how
to go about it. Also not sure which combination of the latest q35
default settings are valid combinations to try either, because it
seems that multiple things have changed related to pcie-root-port
defaults and other machine options. I am happy to run tests and
provide feedback if that helps identify the issue.
I am using "Linux arch 5.4.0-rc6-mainline" kernel on ArchLinux host
with AMD Navi reset pci quirk patch applied.
My working Qemu command line is this:
QEMU_AUDIO_DRV=pa \
QEMU_PA_SERVER=/run/user/1000/pulse/native \
/usr/bin/qemu-system-x86_64 \
-name windows \
-m 16g \
-accel kvm \
-machine pc-q35-3.0,accel=kvm,pflash0=ovmf0,pflash1=ovmf1 \
-blockdev
node-name=ovmf0,driver=file,filename=/virt/qemu/roms/OVMF_CODE.fd,read-only=on \
-blockdev
node-name=ovmf1,driver=file,filename=/virt/qemu/machines/windows/OVMF_VARS.fd \
-boot menu=on \
-global kvm-pit.lost_tick_policy=discard \
-no-hpet \
-rtc base=utc,clock=host,driftfix=slew \
-cpu
host,kvm=off,hv_vendor_id=RedHatRedHat,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_reset,hv_vpindex,hv_runtime,hv_relaxed,hv_synic,hv_stimer
\
-smp sockets=1,cores=4,threads=1 \
-nodefaults \
-netdev bridge,br=br0,id=net0 \
-device virtio-net-pci,netdev=net0,addr=19.0,mac=52:54:00:12:34:77 \
-device virtio-scsi-pci \
-blockdev
raw,node-name=disk0,cache.direct=off,discard=unmap,file.driver=file,file.aio=threads,file.filename=/virt/qemu/machines/windows/os.raw
\
-device scsi-hd,drive=disk0,rotation_rate=1 \
-blockdev
raw,node-name=disk1,cache.direct=off,discard=unmap,file.driver=file,file.aio=threads,file.filename=/virt/qemu/machines/windows/data.raw
\
-device scsi-hd,drive=disk1,rotation_rate=1 \
-drive
index=0,if=ide,media=cdrom,readonly,file=/virt/qemu/isos/Win10_1903_V2_English_x64.iso
\
-drive
index=1,if=ide,media=cdrom,readonly,file=/virt/qemu/isos/virtio-win-0.1.173.iso
\
-device ich9-intel-hda,addr=1b.0 \
-device hda-output \
-monitor stdio \
-display none \
-vga none \
-device
pcie-root-port,id=pcierp0,chassis=1,slot=1,addr=1c.0,disable-acs=on,multifunction=on
\
-device pcie-root-port,id=pcierp1,chassis=2,slot=2,addr=1c.1,disable-acs=on \
-device x3130-upstream,bus=pcierp0,id=pcieu0 \
-device xio3130-downstream,bus=pcieu0,id=pcied0,chassis=11,slot=11 \
-device vfio-pci,host=03:00.0,bus=pcied0,addr=00.0,multifunction=on \
-device vfio-pci,host=03:00.1,bus=pcied0,addr=00.1 \
-device qemu-xhci,addr=1d.0 \
-device usb-host,vendorid=0x258a,productid=0x0001 \
-device usb-host,vendorid=0x1bcf,productid=0x0005 ;
Thank you!
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