Hi Michael, 2014-07-30 21:16 GMT+08:00 Michael S. Tsirkin <m...@redhat.com>: > On Wed, Jul 30, 2014 at 08:24:04PM +0800, Le Tan wrote: >> Hi, >> I am testing vfio in L1 with my VT-d emulation project. I assigned one >> of the two AHCI controllers in L1 to L2 via vfio. After I ran the QEMU >> in L1, it complains that: >> qemu-system-x86_64: vfio: Cannot reset device 0000:00:03.0, no >> available reset mechanism. >> qemu-system-x86_64: vfio: Cannot reset device 0000:00:03.0, no >> available reset mechanism. >> >> Then L2 paused when the SeaBIOS executed in ahci_controller_setup(). I >> look into this and found that: >> val = ahci_ctrl_readl(ctrl, HOST_CTL); >> ahci_ctrl_writel(ctrl, HOST_CTL, val | HOST_CTL_AHCI_EN); >> When the BIOS tried to read the HOST_CTL, it returns 0x80000002, which >> bit 2 (Interrupt Enable) is 1. The AHCI manual says that this bit >> should be cleared by default. So maybe L1 didn't reset the device >> before assigning it to L2? >> Then the BIOS tried to write back to HOST_CTL and it was stuck here. :( >> >> So can anyone give me some advice? About the state of PCI device or >> bus-level reset? >> >> Here is the detail of the environment and the way I did the vfio. >> 1. lspci in L1 said: >> 00:03.0 SATA controller [0106]: Intel Corporation 82801IR/IO/IH >> (ICH9R/DO/DH) 6 port SATA Controller [AHCI mode] [8086:2922] (rev 02) >> 00:1f.0 ISA bridge [0601]: Intel Corporation 82801IB (ICH9) LPC >> Interface Controller [8086:2918] (rev 02) >> 00:1f.2 SATA controller [0106]: Intel Corporation 82801IR/IO/IH >> (ICH9R/DO/DH) 6 port SATA Controller [AHCI mode] [8086:2922] (rev 02) >> 00:1f.3 SMBus [0c05]: Intel Corporation 82801I (ICH9 Family) SMBus >> Controller [8086:2930] (rev 02) >> 2. Unbind 00:03.0 and do vfio: >> modprobe -r vfio_iommu_type1 >> modprobe vfio_iommu_type1 allow_unsafe_interrupts=1 >> modprobe vfio-pci >> echo 0000:00:03.0 > /sys/bus/pci/devices/0000\:00\:03.0/driver/unbind >> echo "8086 2922" > /sys/bus/pci/drivers/vfio-pci/new_id >> 3. run L2 with "-device vfio-pci,host=00:03.0" >> >> Any help is appreciated! Thanks very much! >> >> Regards, >> Le > > Clearly, bus level reset can't work for the root bus :)
Thanks very much! I test the vfio with a second-bus ahci controller and it didn't complain about the lack of reset mechanism. :) And the return val of HOST_CTL is normal now (the same as emulated ahci controller). However, it still paused when the BIOS tried to write to the HOST_CTL. Do you have any idea? And we should just test vfio and legacy pci-assignment with second bus devices, not considering the root-bus devices? Thanks again! Regards, Le > -- > MST
