scsi_cmd_xfer_mode() is used to specify the xfer direction for SCSI commands that come in from the guest. If the direction is set incorrectly this will eventually cause QEMU to kernel-panic the guest.
Add UNMAP/WRITESAME16/ATAPASSTHROUGH as commands that send data to the device. Without this change, recent kernels will send both UNMAP as well as ATAPASSTHROUGH commands to any /dev/sg* device, which due to the incorrect xfer direction very quickly causes the guest kernel to crash. Example causing a crash without the patch applied: ./x86_64-softmmu/qemu-system-x86_64 -m 1024 -enable-kvm -cdrom linuxmint-12-gnome-dvd-64bit.iso -drive file=/dev/sg4,if=scsi,bus=0,unit=6 Signed-off-by: Ronnie Sahlberg <ronniesahlb...@gmail.com> --- hw/scsi-bus.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c index dbdb99c..bca2be8 100644 --- a/hw/scsi-bus.c +++ b/hw/scsi-bus.c @@ -920,6 +920,8 @@ static void scsi_cmd_xfer_mode(SCSICommand *cmd) case UPDATE_BLOCK: case WRITE_LONG_10: case WRITE_SAME_10: + case WRITE_SAME_16: + case UNMAP: case SEARCH_HIGH_12: case SEARCH_EQUAL_12: case SEARCH_LOW_12: @@ -929,6 +931,7 @@ static void scsi_cmd_xfer_mode(SCSICommand *cmd) case SEND_DVD_STRUCTURE: case PERSISTENT_RESERVE_OUT: case MAINTENANCE_OUT: + case ATA_PASSTHROUGH: cmd->mode = SCSI_XFER_TO_DEV; break; default: -- 1.7.3.1