Patchwork lsi53c895a: add support for ABORT messages

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Submitter Bernhard Kohl
Date Sept. 6, 2010, 2:42 p.m.
Message ID <1283784174-30436-1-git-send-email-bernhard.kohl@nsn.com>
Download mbox | patch
Permalink /patch/63926/
State New
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Comments

Bernhard Kohl - Sept. 6, 2010, 2:42 p.m.
If these messages are not handled correctly the guest driver may hang.

Always mandatory:
- ABORT
- BUS DEVICE RESET

Mandatory if tagged queuing is implemented (which disks usually do):
- ABORT TAG
- CLEAR QUEUE

Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
---
 hw/lsi53c895a.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 57 insertions(+), 0 deletions(-)
Kevin Wolf - Oct. 7, 2010, 11:27 a.m.
Am 06.09.2010 16:42, schrieb Bernhard Kohl:
> If these messages are not handled correctly the guest driver may hang.
> 
> Always mandatory:
> - ABORT
> - BUS DEVICE RESET
> 
> Mandatory if tagged queuing is implemented (which disks usually do):
> - ABORT TAG
> - CLEAR QUEUE
> 
> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>

Nicholas, as you seem to have touched the lsi code recently, care to
review this one? Assuming that you are reasonably familiar with both the
hardware and the code, you should be quicker than me with this.

Kevin

> ---
>  hw/lsi53c895a.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 57 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
> index 5eaf69e..40f2d10 100644
> --- a/hw/lsi53c895a.c
> +++ b/hw/lsi53c895a.c
> @@ -846,6 +846,18 @@ static void lsi_do_msgout(LSIState *s)
>  {
>      uint8_t msg;
>      int len;
> +    uint32_t current_tag;
> +    SCSIDevice *current_dev;
> +    lsi_request *p, *p_next;
> +    int id;
> +
> +    if (s->current) {
> +        current_tag = s->current->tag;
> +    } else {
> +        current_tag = s->select_tag;
> +    }
> +    id = (current_tag >> 8) & 0xf;
> +    current_dev = s->bus.devs[id];
>  
>      DPRINTF("MSG out len=%d\n", s->dbc);
>      while (s->dbc) {
> @@ -890,6 +902,51 @@ static void lsi_do_msgout(LSIState *s)
>              BADF("ORDERED queue not implemented\n");
>              s->select_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
>              break;
> +        case 0x0d:
> +            /* The ABORT TAG message clears the current I/O process only. */
> +            DPRINTF("MSG: ABORT TAG tag=0x%x\n", current_tag);
> +            current_dev->info->cancel_io(current_dev, current_tag);
> +            lsi_disconnect(s);
> +            break;
> +        case 0x06:
> +        case 0x0e:
> +        case 0x0c:
> +            /* The ABORT message clears all I/O processes for the selecting
> +               initiator on the specified logical unit of the target. */
> +            if (msg == 0x06) {
> +                DPRINTF("MSG: ABORT tag=0x%x\n", current_tag);
> +            }
> +            /* The CLEAR QUEUE message clears all I/O processes for all
> +               initiators on the specified logical unit of the target. */
> +            if (msg == 0x0e) {
> +                DPRINTF("MSG: CLEAR QUEUE tag=0x%x\n", current_tag);
> +            }
> +            /* The BUS DEVICE RESET message clears all I/O processes for all
> +               initiators on all logical units of the target. */
> +            if (msg == 0x0c) {
> +                DPRINTF("MSG: BUS DEVICE RESET tag=0x%x\n", current_tag);
> +            }
> +
> +            /* clear the current I/O process */
> +            current_dev->info->cancel_io(current_dev, current_tag);
> +
> +            /* As the current implemented devices scsi_disk and scsi_generic
> +               only support one LUN, we don't need to keep track of LUNs.
> +               Clearing I/O processes for other initiators could be possible
> +               for scsi_generic by sending a SG_SCSI_RESET to the /dev/sgX
> +               device, but this is currently not implemented (and seems not
> +               to be really necessary). So let's simply clear all queued
> +               commands for the current device: */
> +            id = current_tag & 0x0000ff00;
> +            QTAILQ_FOREACH_SAFE(p, &s->queue, next, p_next) {
> +                if ((p->tag & 0x0000ff00) == id) {
> +                    current_dev->info->cancel_io(current_dev, p->tag);
> +                    QTAILQ_REMOVE(&s->queue, p, next);
> +                }
> +            }
> +
> +            lsi_disconnect(s);
> +            break;
>          default:
>              if ((msg & 0x80) == 0) {
>                  goto bad;
Peter Lieven - March 8, 2011, 11:04 p.m.
Am 07.10.2010 um 13:27 schrieb Kevin Wolf:

> Am 06.09.2010 16:42, schrieb Bernhard Kohl:
>> If these messages are not handled correctly the guest driver may hang.
>> 
>> Always mandatory:
>> - ABORT
>> - BUS DEVICE RESET
>> 
>> Mandatory if tagged queuing is implemented (which disks usually do):
>> - ABORT TAG
>> - CLEAR QUEUE
>> 
>> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
> 
> Nicholas, as you seem to have touched the lsi code recently, care to
> review this one? Assuming that you are reasonably familiar with both the
> hardware and the code, you should be quicker than me with this.

Is there a reason why this patch was never added to the stable qemu-kvm release?
At least int qemu-kvm-0.14.0 I still can't find it.

Peter


> 
> Kevin
> 
>> ---
>> hw/lsi53c895a.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 files changed, 57 insertions(+), 0 deletions(-)
>> 
>> diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
>> index 5eaf69e..40f2d10 100644
>> --- a/hw/lsi53c895a.c
>> +++ b/hw/lsi53c895a.c
>> @@ -846,6 +846,18 @@ static void lsi_do_msgout(LSIState *s)
>> {
>>     uint8_t msg;
>>     int len;
>> +    uint32_t current_tag;
>> +    SCSIDevice *current_dev;
>> +    lsi_request *p, *p_next;
>> +    int id;
>> +
>> +    if (s->current) {
>> +        current_tag = s->current->tag;
>> +    } else {
>> +        current_tag = s->select_tag;
>> +    }
>> +    id = (current_tag >> 8) & 0xf;
>> +    current_dev = s->bus.devs[id];
>> 
>>     DPRINTF("MSG out len=%d\n", s->dbc);
>>     while (s->dbc) {
>> @@ -890,6 +902,51 @@ static void lsi_do_msgout(LSIState *s)
>>             BADF("ORDERED queue not implemented\n");
>>             s->select_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
>>             break;
>> +        case 0x0d:
>> +            /* The ABORT TAG message clears the current I/O process only. */
>> +            DPRINTF("MSG: ABORT TAG tag=0x%x\n", current_tag);
>> +            current_dev->info->cancel_io(current_dev, current_tag);
>> +            lsi_disconnect(s);
>> +            break;
>> +        case 0x06:
>> +        case 0x0e:
>> +        case 0x0c:
>> +            /* The ABORT message clears all I/O processes for the selecting
>> +               initiator on the specified logical unit of the target. */
>> +            if (msg == 0x06) {
>> +                DPRINTF("MSG: ABORT tag=0x%x\n", current_tag);
>> +            }
>> +            /* The CLEAR QUEUE message clears all I/O processes for all
>> +               initiators on the specified logical unit of the target. */
>> +            if (msg == 0x0e) {
>> +                DPRINTF("MSG: CLEAR QUEUE tag=0x%x\n", current_tag);
>> +            }
>> +            /* The BUS DEVICE RESET message clears all I/O processes for all
>> +               initiators on all logical units of the target. */
>> +            if (msg == 0x0c) {
>> +                DPRINTF("MSG: BUS DEVICE RESET tag=0x%x\n", current_tag);
>> +            }
>> +
>> +            /* clear the current I/O process */
>> +            current_dev->info->cancel_io(current_dev, current_tag);
>> +
>> +            /* As the current implemented devices scsi_disk and scsi_generic
>> +               only support one LUN, we don't need to keep track of LUNs.
>> +               Clearing I/O processes for other initiators could be possible
>> +               for scsi_generic by sending a SG_SCSI_RESET to the /dev/sgX
>> +               device, but this is currently not implemented (and seems not
>> +               to be really necessary). So let's simply clear all queued
>> +               commands for the current device: */
>> +            id = current_tag & 0x0000ff00;
>> +            QTAILQ_FOREACH_SAFE(p, &s->queue, next, p_next) {
>> +                if ((p->tag & 0x0000ff00) == id) {
>> +                    current_dev->info->cancel_io(current_dev, p->tag);
>> +                    QTAILQ_REMOVE(&s->queue, p, next);
>> +                }
>> +            }
>> +
>> +            lsi_disconnect(s);
>> +            break;
>>         default:
>>             if ((msg & 0x80) == 0) {
>>                 goto bad;
> 
>
Stefan Hajnoczi - March 9, 2011, 5:33 a.m.
On Tue, Mar 8, 2011 at 11:04 PM, Peter Lieven <pl@dlh.net> wrote:
>
> Am 07.10.2010 um 13:27 schrieb Kevin Wolf:
>
>> Am 06.09.2010 16:42, schrieb Bernhard Kohl:
>>> If these messages are not handled correctly the guest driver may hang.
>>>
>>> Always mandatory:
>>> - ABORT
>>> - BUS DEVICE RESET
>>>
>>> Mandatory if tagged queuing is implemented (which disks usually do):
>>> - ABORT TAG
>>> - CLEAR QUEUE
>>>
>>> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>

A related bug was filed yesterday and this patch probably fixes it:

https://bugs.launchpad.net/qemu/+bug/731344

Stefan
Kevin Wolf - March 9, 2011, 8:47 a.m.
Am 09.03.2011 00:04, schrieb Peter Lieven:
> 
> Am 07.10.2010 um 13:27 schrieb Kevin Wolf:
> 
>> Am 06.09.2010 16:42, schrieb Bernhard Kohl:
>>> If these messages are not handled correctly the guest driver may hang.
>>>
>>> Always mandatory:
>>> - ABORT
>>> - BUS DEVICE RESET
>>>
>>> Mandatory if tagged queuing is implemented (which disks usually do):
>>> - ABORT TAG
>>> - CLEAR QUEUE
>>>
>>> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
>>
>> Nicholas, as you seem to have touched the lsi code recently, care to
>> review this one? Assuming that you are reasonably familiar with both the
>> hardware and the code, you should be quicker than me with this.
> 
> Is there a reason why this patch was never added to the stable qemu-kvm release?
> At least int qemu-kvm-0.14.0 I still can't find it.

The reason is that it still didn't get a review.

Kevin
Bernhard Kohl - March 9, 2011, 9:25 a.m.
Am 09.03.2011 09:47, schrieb ext Kevin Wolf:
> Am 09.03.2011 00:04, schrieb Peter Lieven:
>> Am 07.10.2010 um 13:27 schrieb Kevin Wolf:
>>
>>> Am 06.09.2010 16:42, schrieb Bernhard Kohl:
>>>> If these messages are not handled correctly the guest driver may hang.
>>>>
>>>> Always mandatory:
>>>> - ABORT
>>>> - BUS DEVICE RESET
>>>>
>>>> Mandatory if tagged queuing is implemented (which disks usually do):
>>>> - ABORT TAG
>>>> - CLEAR QUEUE
>>>>
>>>> Signed-off-by: Bernhard Kohl<bernhard.kohl@nsn.com>
>>> Nicholas, as you seem to have touched the lsi code recently, care to
>>> review this one? Assuming that you are reasonably familiar with both the
>>> hardware and the code, you should be quicker than me with this.
>> Is there a reason why this patch was never added to the stable qemu-kvm release?
>> At least int qemu-kvm-0.14.0 I still can't find it.
> The reason is that it still didn't get a review.
>
I still depend on this patch. It's needed for our legacy guest OS.
It's heavily in use here with STGT iSCSI disks via scsi-generic.

Bernhard
Peter Lieven - March 9, 2011, 9:38 a.m.
Am 09.03.2011 um 10:25 schrieb Bernhard Kohl:

> Am 09.03.2011 09:47, schrieb ext Kevin Wolf:
>> Am 09.03.2011 00:04, schrieb Peter Lieven:
>>> Am 07.10.2010 um 13:27 schrieb Kevin Wolf:
>>> 
>>>> Am 06.09.2010 16:42, schrieb Bernhard Kohl:
>>>>> If these messages are not handled correctly the guest driver may hang.
>>>>> 
>>>>> Always mandatory:
>>>>> - ABORT
>>>>> - BUS DEVICE RESET
>>>>> 
>>>>> Mandatory if tagged queuing is implemented (which disks usually do):
>>>>> - ABORT TAG
>>>>> - CLEAR QUEUE
>>>>> 
>>>>> Signed-off-by: Bernhard Kohl<bernhard.kohl@nsn.com>
>>>> Nicholas, as you seem to have touched the lsi code recently, care to
>>>> review this one? Assuming that you are reasonably familiar with both the
>>>> hardware and the code, you should be quicker than me with this.
>>> Is there a reason why this patch was never added to the stable qemu-kvm release?
>>> At least int qemu-kvm-0.14.0 I still can't find it.
>> The reason is that it still didn't get a review.
>> 
> I still depend on this patch. It's needed for our legacy guest OS.
> It's heavily in use here with STGT iSCSI disks via scsi-generic.

We use it in qemu-0.12.5 as well for a very long time. I saw an assertion last year
with errors of unimplemented abort feature preceding. Since we use this patch
we have never seen it again.

Peter

> 
> Bernhard
Aurelien Jarno - April 1, 2011, 8:16 p.m.
On Mon, Sep 06, 2010 at 04:42:54AM -0000, Bernhard Kohl wrote:
> If these messages are not handled correctly the guest driver may hang.
> 
> Always mandatory:
> - ABORT
> - BUS DEVICE RESET
> 
> Mandatory if tagged queuing is implemented (which disks usually do):
> - ABORT TAG
> - CLEAR QUEUE
> 
> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
> 
> ---
> hw/lsi53c895a.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 57 insertions(+), 0 deletions(-)

Thanks, applied.

> diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
> index 5eaf69e..40f2d10 100644
> --- a/hw/lsi53c895a.c
> +++ b/hw/lsi53c895a.c
> @@ -846,6 +846,18 @@ static void lsi_do_msgout(LSIState *s)
>  {
>      uint8_t msg;
>      int len;
> +    uint32_t current_tag;
> +    SCSIDevice *current_dev;
> +    lsi_request *p, *p_next;
> +    int id;
> +
> +    if (s->current) {
> +        current_tag = s->current->tag;
> +    } else {
> +        current_tag = s->select_tag;
> +    }
> +    id = (current_tag >> 8) & 0xf;
> +    current_dev = s->bus.devs[id];
>  
>      DPRINTF("MSG out len=%d\n", s->dbc);
>      while (s->dbc) {
> @@ -890,6 +902,51 @@ static void lsi_do_msgout(LSIState *s)
>              BADF("ORDERED queue not implemented\n");
>              s->select_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
>              break;
> +        case 0x0d:
> +            /* The ABORT TAG message clears the current I/O process only. */
> +            DPRINTF("MSG: ABORT TAG tag=0x%x\n", current_tag);
> +            current_dev->info->cancel_io(current_dev, current_tag);
> +            lsi_disconnect(s);
> +            break;
> +        case 0x06:
> +        case 0x0e:
> +        case 0x0c:
> +            /* The ABORT message clears all I/O processes for the selecting
> +               initiator on the specified logical unit of the target. */
> +            if (msg == 0x06) {
> +                DPRINTF("MSG: ABORT tag=0x%x\n", current_tag);
> +            }
> +            /* The CLEAR QUEUE message clears all I/O processes for all
> +               initiators on the specified logical unit of the target. */
> +            if (msg == 0x0e) {
> +                DPRINTF("MSG: CLEAR QUEUE tag=0x%x\n", current_tag);
> +            }
> +            /* The BUS DEVICE RESET message clears all I/O processes for all
> +               initiators on all logical units of the target. */
> +            if (msg == 0x0c) {
> +                DPRINTF("MSG: BUS DEVICE RESET tag=0x%x\n", current_tag);
> +            }
> +
> +            /* clear the current I/O process */
> +            current_dev->info->cancel_io(current_dev, current_tag);
> +
> +            /* As the current implemented devices scsi_disk and scsi_generic
> +               only support one LUN, we don't need to keep track of LUNs.
> +               Clearing I/O processes for other initiators could be possible
> +               for scsi_generic by sending a SG_SCSI_RESET to the /dev/sgX
> +               device, but this is currently not implemented (and seems not
> +               to be really necessary). So let's simply clear all queued
> +               commands for the current device: */
> +            id = current_tag & 0x0000ff00;
> +            QTAILQ_FOREACH_SAFE(p, &s->queue, next, p_next) {
> +                if ((p->tag & 0x0000ff00) == id) {
> +                    current_dev->info->cancel_io(current_dev, p->tag);
> +                    QTAILQ_REMOVE(&s->queue, p, next);
> +                }
> +            }
> +
> +            lsi_disconnect(s);
> +            break;
>          default:
>              if ((msg & 0x80) == 0) {
>                  goto bad;
Peter Lieven - April 26, 2011, 2:46 p.m.
On 09.03.2011 10:25, Bernhard Kohl wrote:
> Am 09.03.2011 09:47, schrieb ext Kevin Wolf:
>> Am 09.03.2011 00:04, schrieb Peter Lieven:
>>> Am 07.10.2010 um 13:27 schrieb Kevin Wolf:
>>>
>>>> Am 06.09.2010 16:42, schrieb Bernhard Kohl:
>>>>> If these messages are not handled correctly the guest driver may 
>>>>> hang.
>>>>>
>>>>> Always mandatory:
>>>>> - ABORT
>>>>> - BUS DEVICE RESET
>>>>>
>>>>> Mandatory if tagged queuing is implemented (which disks usually do):
>>>>> - ABORT TAG
>>>>> - CLEAR QUEUE
>>>>>
>>>>> Signed-off-by: Bernhard Kohl<bernhard.kohl@nsn.com>
>>>> Nicholas, as you seem to have touched the lsi code recently, care to
>>>> review this one? Assuming that you are reasonably familiar with 
>>>> both the
>>>> hardware and the code, you should be quicker than me with this.
>>> Is there a reason why this patch was never added to the stable 
>>> qemu-kvm release?
>>> At least int qemu-kvm-0.14.0 I still can't find it.
>> The reason is that it still didn't get a review.
>>
> I still depend on this patch. It's needed for our legacy guest OS.
> It's heavily in use here with STGT iSCSI disks via scsi-generic.

i recently saw some qemu-kvm 0.12.5 guests with scsi and this patch 
applies crashing when
we updated our backend iscsi storages. (short interrupt in traffic flow, 
iscsi disconnect + reconnect)

i always see:
lsi_scsi: error: ORDERED queue not implemented

and then either the maschine just hangs or it even aborts due to this 
assertion:
qemu-kvm-0.12.5: /usr/src/qemu-kvm-0.12.5/hw/lsi53c895a.c:596: 
lsi_reselect: Assertion `s->current == ((void *)0)' failed.

any ideas?

peter


>
> Bernhard
>
Michael Tokarev - April 26, 2011, 5:04 p.m.
26.04.2011 18:46, Peter Lieven wrote:
[]
> i recently saw some qemu-kvm 0.12.5 guests with scsi and this patch
> applies crashing when
> we updated our backend iscsi storages. (short interrupt in traffic flow,
> iscsi disconnect + reconnect)
> 
> i always see:
> lsi_scsi: error: ORDERED queue not implemented
> 
> and then either the maschine just hangs or it even aborts due to this
> assertion:
> qemu-kvm-0.12.5: /usr/src/qemu-kvm-0.12.5/hw/lsi53c895a.c:596:
> lsi_reselect: Assertion `s->current == ((void *)0)' failed.

http://bugs.debian.org/613413 talks about this very issue too ;)

> any ideas?

Unfortunately, no, except that it looks like scsi support is
not of production quality still.

/mjt
Peter Lieven - April 27, 2011, 1:06 p.m.
On 26.04.2011 19:04, Michael Tokarev wrote:
> 26.04.2011 18:46, Peter Lieven wrote:
> []
>> i recently saw some qemu-kvm 0.12.5 guests with scsi and this patch
>> applies crashing when
>> we updated our backend iscsi storages. (short interrupt in traffic flow,
>> iscsi disconnect + reconnect)
>>
>> i always see:
>> lsi_scsi: error: ORDERED queue not implemented
>>
>> and then either the maschine just hangs or it even aborts due to this
>> assertion:
>> qemu-kvm-0.12.5: /usr/src/qemu-kvm-0.12.5/hw/lsi53c895a.c:596:
>> lsi_reselect: Assertion `s->current == ((void *)0)' failed.
> http://bugs.debian.org/613413 talks about this very issue too ;)
>
>> any ideas?
> Unfortunately, no, except that it looks like scsi support is
> not of production quality still.
Do you know a reliable way to reproduce the ORDERED queue not 
implemented error?
I tried with 0.14.0, but I were not able to. I will now try with 0.12.5.

However in 0.14.0 I manage to freeze a VM when copying data from an SCSI 
device and
then temporarely interrupt the connection to my iSCSI storage which is 
used as backend
on the host. Strangely, I cannot reprocude this when I run qemu-kvm in 
gdb. There I just
see some SIGPIPE errors, but when I continue everything is fine.

 From what I read from the SCSI2 specs a target should either implement 
all tagged queue
commands or none. If tagged queing is not supported it should send a 
reject message, but
continue with the following command.

http://ldkelley.com/SCSI2/SCSI2/SCSI2-06.html#6.6.17

Can somebody who is more familiar with SCSI look into this? SCSI drive 
support
seems to be serverly broken.

Peter

> /mjt

Patch

diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index 5eaf69e..40f2d10 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -846,6 +846,18 @@  static void lsi_do_msgout(LSIState *s)
 {
     uint8_t msg;
     int len;
+    uint32_t current_tag;
+    SCSIDevice *current_dev;
+    lsi_request *p, *p_next;
+    int id;
+
+    if (s->current) {
+        current_tag = s->current->tag;
+    } else {
+        current_tag = s->select_tag;
+    }
+    id = (current_tag >> 8) & 0xf;
+    current_dev = s->bus.devs[id];
 
     DPRINTF("MSG out len=%d\n", s->dbc);
     while (s->dbc) {
@@ -890,6 +902,51 @@  static void lsi_do_msgout(LSIState *s)
             BADF("ORDERED queue not implemented\n");
             s->select_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
             break;
+        case 0x0d:
+            /* The ABORT TAG message clears the current I/O process only. */
+            DPRINTF("MSG: ABORT TAG tag=0x%x\n", current_tag);
+            current_dev->info->cancel_io(current_dev, current_tag);
+            lsi_disconnect(s);
+            break;
+        case 0x06:
+        case 0x0e:
+        case 0x0c:
+            /* The ABORT message clears all I/O processes for the selecting
+               initiator on the specified logical unit of the target. */
+            if (msg == 0x06) {
+                DPRINTF("MSG: ABORT tag=0x%x\n", current_tag);
+            }
+            /* The CLEAR QUEUE message clears all I/O processes for all
+               initiators on the specified logical unit of the target. */
+            if (msg == 0x0e) {
+                DPRINTF("MSG: CLEAR QUEUE tag=0x%x\n", current_tag);
+            }
+            /* The BUS DEVICE RESET message clears all I/O processes for all
+               initiators on all logical units of the target. */
+            if (msg == 0x0c) {
+                DPRINTF("MSG: BUS DEVICE RESET tag=0x%x\n", current_tag);
+            }
+
+            /* clear the current I/O process */
+            current_dev->info->cancel_io(current_dev, current_tag);
+
+            /* As the current implemented devices scsi_disk and scsi_generic
+               only support one LUN, we don't need to keep track of LUNs.
+               Clearing I/O processes for other initiators could be possible
+               for scsi_generic by sending a SG_SCSI_RESET to the /dev/sgX
+               device, but this is currently not implemented (and seems not
+               to be really necessary). So let's simply clear all queued
+               commands for the current device: */
+            id = current_tag & 0x0000ff00;
+            QTAILQ_FOREACH_SAFE(p, &s->queue, next, p_next) {
+                if ((p->tag & 0x0000ff00) == id) {
+                    current_dev->info->cancel_io(current_dev, p->tag);
+                    QTAILQ_REMOVE(&s->queue, p, next);
+                }
+            }
+
+            lsi_disconnect(s);
+            break;
         default:
             if ((msg & 0x80) == 0) {
                 goto bad;