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
