Re: [Qemu-devel] qemu seabios issue with vhost-scsi

[Badari Pulavarty <pbadari@us.ibm.com>]

On 05/23/2013 08:30 AM, Paolo Bonzini wrote:
> Il 23/05/2013 17:27, Asias He ha scritto:
>> On Thu, May 23, 2013 at 04:58:05PM +0200, Paolo Bonzini wrote:
>>> Il 23/05/2013 16:48, Badari Pulavarty ha scritto:
>>>>> The common virtio-scsi code in QEMU should guard against this.  In
>>>>> virtio-blk data plane I hit a similar case and ended up starting the
>>>>> data plane thread (equivalent to vhost here) *before* the status
>>>>> register is set to DRIVER_OK.
>>>> Thats exactly what my debug in vhost_scsi_set_status() shows.
>>>>
>>>> set status started 0 val 0
>>>> set status started 0 val 0
>>>> set status started 0 val 0
>>>> set status started 0 val 0
>>>> set status started 0 val 0
>>>> set status started 0 val 3
>>>> Program received signal SIGSEGV, Segmentation fault.
>>>>
>>>> We never got a chance to call vhost_scsi_start() as we are waiting
>>>> for DRIVER_OK.
>> Reproduced the SIGSEGV and verified that replacing the bios.bin with the
>> one from seabios.git makes the guest boot.
> This should fix it:
>
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 08dd3f3..3139355 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -266,7 +266,7 @@ fail:
>
>   static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
>   {
> -    VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> +    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
>       VirtIOSCSIReq *req;
>
>       while ((req = virtio_scsi_pop_req(s, vq))) {
> @@ -347,9 +347,8 @@ static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
>
>   static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
>   {
> -    /* use non-QOM casts in the data path */
> -    VirtIOSCSI *s = (VirtIOSCSI *)vdev;
> -    VirtIOSCSICommon *vs = &s->parent_obj;
> +    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
> +    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
>
>       VirtIOSCSIReq *req;
>       int n;
>
> Paolo
>
Hmm.. Not quite..

(gdb) run -cpu qemu64 --enable-kvm -m 4096 -drive 
file=/var/lib/libvirt/images/lnx.img,if=ide,cache=writethrough -device 
vhost-scsi-pci,wwpn=naa.6001405bd4e8476d,event_idx=off -vnc :10 -boot d
Starting program: /root/qemu/x86_64-softmmu/qemu-system-x86_64 -cpu 
qemu64 --enable-kvm -m 4096 -drive 
file=/var/lib/libvirt/images/lnx.img,if=ide,cache=writethrough -device 
vhost-scsi-pci,wwpn=naa.6001405bd4e8476d,event_idx=off -vnc :10 -boot d
warning: no loadable sections found in added symbol-file system-supplied 
DSO at 0x7ffff7ffa000
[Thread debugging using libthread_db enabled]
[New Thread 0x7ffff1c1c700 (LWP 2458)]
[New Thread 0x7ffff1239700 (LWP 2459)]
[New Thread 0x7fffeb7ff700 (LWP 2462)]
set status started 0 val 0
set status started 0 val 0
set status started 0 val 0
set status started 0 val 0
set status started 0 val 0
set status started 0 val 3
/root/qemu/hw/scsi/virtio-scsi.c:356:virtio_scsi_handle_cmd: Object 
0x5555565aca88 is not an instance of type virtio-scsi-device

Program received signal SIGABRT, Aborted.
[Switching to Thread 0x7ffff1239700 (LWP 2459)]
0x00007ffff5cf18a5 in raise () from /lib64/libc.so.6
Missing separate debuginfos, use: debuginfo-install 
cyrus-sasl-gssapi-2.1.23-13.el6_3.1.x86_64 
cyrus-sasl-lib-2.1.23-13.el6_3.1.x86_64 
cyrus-sasl-md5-2.1.23-13.el6_3.1.x86_64 
cyrus-sasl-plain-2.1.23-13.el6_3.1.x86_64 db4-4.7.25-17.el6.x86_64 
glib2-2.22.5-7.el6.x86_64 glibc-2.12-1.107.el6.x86_64 
gnutls-2.8.5-10.el6.x86_64 keyutils-libs-1.4-4.el6.x86_64 
krb5-libs-1.10.3-10.el6.x86_64 libcom_err-1.41.12-14.el6.x86_64 
libcurl-7.19.7-35.el6.x86_64 libgcrypt-1.4.5-9.el6_2.2.x86_64 
libgpg-error-1.7-4.el6.x86_64 libidn-1.18-2.el6.x86_64 
libpng-1.2.49-1.el6_2.x86_64 libselinux-2.0.94-5.3.el6.x86_64 
libssh2-1.4.2-1.el6.x86_64 libtasn1-2.3-3.el6_2.1.x86_64 
ncurses-libs-5.7-3.20090208.el6.x86_64 nspr-4.9.2-1.el6.x86_64 
nss-3.14.0.0-12.el6.x86_64 nss-softokn-freebl-3.12.9-11.el6.x86_64 
nss-util-3.14.0.0-2.el6.x86_64 openldap-2.4.23-31.el6.x86_64 
openssl-1.0.0-27.el6.x86_64 pixman-0.26.2-4.el6.x86_64 
zlib-1.2.3-29.el6.x86_64
(gdb) bt
#0  0x00007ffff5cf18a5 in raise () from /lib64/libc.so.6
#1  0x00007ffff5cf3085 in abort () from /lib64/libc.so.6
#2  0x00005555557230d0 in object_dynamic_cast_assert 
(obj=0x5555565aca88, typename=0x5555558a56e5 "virtio-scsi-device", 
file=0x5555558bda30 "/root/qemu/hw/scsi/virtio-scsi.c", line=356,
     func=<value optimized out>) at qom/object.c:456
#3  0x00005555557a5ef1 in virtio_scsi_handle_cmd (vdev=0x5555565aca88, 
vq=0x5555565d2160) at /root/qemu/hw/scsi/virtio-scsi.c:356
#4  0x00005555557b3a60 in access_with_adjusted_size (addr=16, 
value=0x7ffff1238b78, size=2, access_size_min=<value optimized out>, 
access_size_max=<value optimized out>, access=
     0x5555557b51d0 <memory_region_write_accessor>, 
opaque=0x5555565ac940) at /root/qemu/memory.c:364
#5  0x00005555557b408b in memory_region_iorange_write (iorange=<value 
optimized out>, offset=<value optimized out>, width=<value optimized 
out>, data=2) at /root/qemu/memory.c:439
#6  0x00005555557b2ff6 in kvm_handle_io (env=0x555556521af0) at 
/root/qemu/kvm-all.c:1485
#7  kvm_cpu_exec (env=0x555556521af0) at /root/qemu/kvm-all.c:1634
#8  0x000055555576148e in qemu_kvm_cpu_thread_fn (arg=0x555556521af0) at 
/root/qemu/cpus.c:759
#9  0x00007ffff6059851 in start_thread () from /lib64/libpthread.so.0
#10 0x00007ffff5da790d in clone () from /lib64/libc.so.6