[vfio-users] problem with passthrough and unsafe interrupts

[Janusz]

Hello,

I have a question about allowing unsafe interrupts, what exactly is
happening when we allow it? why its unsafe?
I am asking because I am not able to passthrough my gpu without allowing
unsafe interrupts, and have problems in running my virtual machine as it
sometimes rebooting its self before its able to run windows. I know that
there is also problem with using iGPU and not uefi bios, but its also
happening with OVMF and passing uefi rom for my gpu (except that with
OVMF sometimes I also get very high load). without passing VGA,
everyting works fine. Is it possible that its because those unsafe
interrupts?
My hardware: i7 6700k, MSI z170a M7, Sapphire R9 290

those are my options for non-uefi:
-enable-kvm -m 10000 -cpu host -smp 8,cores=4,threads=2,sockets=1
-device
ioh3420,bus=pci.0,addr=1c.0,multifunction=on,port=1,chassis=1,id=root.1
-device vfio-pci,host=01:00.0,multifunction=on,x-vga=on
-device vfio-pci,host=01:00.1

and for uefi:

-drive if=pflash,format=raw,readonly,file=/home/janusz/uefi/OVMF_CODE.fd
-drive if=pflash,format=raw,file=/home/janusz/uefi/OVMF_VARS.fd
-enable-kvm -m 10000 -cpu host -smp 8,cores=4,threads=2,sockets=1
-device
vfio-pci,host=01:00.0,romfile=/home/janusz/uefi/uefi-vga.bin,multifunction=on
-device vfio-pci,host=01:00.1

+ options with assigning /dev/sdb and two usb devices

I am using ovmf build recently from master, kernel 4.2.0 and qemu-2.4.50


My iommu groups:

/sys/kernel/iommu_groups/0/devices/0000:00:00.0
/sys/kernel/iommu_groups/1/devices/0000:00:01.0
/sys/kernel/iommu_groups/1/devices/0000:01:00.0
/sys/kernel/iommu_groups/1/devices/0000:01:00.1
/sys/kernel/iommu_groups/2/devices/0000:00:02.0
/sys/kernel/iommu_groups/3/devices/0000:00:08.0
/sys/kernel/iommu_groups/4/devices/0000:00:14.0
/sys/kernel/iommu_groups/4/devices/0000:00:14.2
/sys/kernel/iommu_groups/5/devices/0000:00:15.0
/sys/kernel/iommu_groups/5/devices/0000:00:15.1
/sys/kernel/iommu_groups/6/devices/0000:00:16.0
/sys/kernel/iommu_groups/7/devices/0000:00:17.0
/sys/kernel/iommu_groups/8/devices/0000:00:1c.0
/sys/kernel/iommu_groups/8/devices/0000:00:1c.2
/sys/kernel/iommu_groups/8/devices/0000:00:1c.7
/sys/kernel/iommu_groups/8/devices/0000:02:00.0
/sys/kernel/iommu_groups/8/devices/0000:03:00.0
/sys/kernel/iommu_groups/8/devices/0000:04:00.0
/sys/kernel/iommu_groups/9/devices/0000:00:1e.0
/sys/kernel/iommu_groups/10/devices/0000:00:1f.0
/sys/kernel/iommu_groups/10/devices/0000:00:1f.2
/sys/kernel/iommu_groups/10/devices/0000:00:1f.3
/sys/kernel/iommu_groups/10/devices/0000:00:1f.4

and lspci:

00:00.0 Host bridge: Intel Corporation Sky Lake Host Bridge/DRAM
Registers (rev 07)
00:01.0 PCI bridge: Intel Corporation Sky Lake PCIe Controller (x16)
(rev 07)
00:02.0 VGA compatible controller: Intel Corporation Sky Lake Integrated
Graphics (rev 06)
00:08.0 System peripheral: Intel Corporation Sky Lake Gaussian Mixture Model
00:14.0 USB controller: Intel Corporation Sunrise Point-H USB 3.0 xHCI
Controller (rev 31)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-H
Thermal subsystem (rev 31)
00:15.0 Signal processing controller: Intel Corporation Sunrise Point-H
LPSS I2C Controller #0 (rev 31)
00:15.1 Signal processing controller: Intel Corporation Sunrise Point-H
LPSS I2C Controller #1 (rev 31)
00:16.0 Communication controller: Intel Corporation Sunrise Point-H CSME
HECI #1 (rev 31)
00:17.0 SATA controller: Intel Corporation Device a102 (rev 31)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root
Port #1 (rev f1)
00:1c.2 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root
Port #3 (rev f1)
00:1c.7 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root
Port #8 (rev f1)
00:1e.0 Signal processing controller: Intel Corporation Sunrise Point-H
LPSS UART #0 (rev 31)
00:1f.0 ISA bridge: Intel Corporation Sunrise Point-H LPC Controller
(rev 31)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-H PMC (rev 31)
00:1f.3 Audio device: Intel Corporation Sunrise Point-H HD Audio (rev 31)
00:1f.4 SMBus: Intel Corporation Sunrise Point-H SMBus (rev 31)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc.
[AMD/ATI] Hawaii PRO [Radeon R9 290]
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Device aac8
02:00.0 USB controller: ASMedia Technology Inc. Device 1242
03:00.0 Ethernet controller: Qualcomm Atheros Device e0a1 (rev 10)
04:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721
Gigabit Ethernet PCI Express (rev 21)


If its not problem of unsafe interrupts, does anyone know why this can
happen?