* lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
@ 2009-10-19 12:14 Tomasz Chmielewski
2009-10-19 13:09 ` Luca Tettamanti
0 siblings, 1 reply; 7+ messages in thread
From: Tomasz Chmielewski @ 2009-10-19 12:14 UTC (permalink / raw)
To: kvm, linux-pci
lspci implies that the virtio block device is a "SCSI storage
controller", i.e.:
00:05.0 SCSI storage controller: Qumranet, Inc. Virtio block device
However, virtio block devide does not have much to do with SCSI (in
sense: sdparm does not think it is a SCSI device; virtio_blk does not
depend on any SCSI moduled like sd_mod).
Is "SCSI storage controller" a proper description for this device?
--
Tomasz Chmielewski
http://wpkg.org
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
2009-10-19 12:14 lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really? Tomasz Chmielewski
@ 2009-10-19 13:09 ` Luca Tettamanti
2009-10-19 13:31 ` Tomasz Chmielewski
0 siblings, 1 reply; 7+ messages in thread
From: Luca Tettamanti @ 2009-10-19 13:09 UTC (permalink / raw)
To: Tomasz Chmielewski; +Cc: kvm, linux-pci
On Mon, Oct 19, 2009 at 2:14 PM, Tomasz Chmielewski <mangoo@wpkg.org> wrote:
> lspci implies that the virtio block device is a "SCSI storage controller",
> i.e.:
>
> 00:05.0 SCSI storage controller: Qumranet, Inc. Virtio block device
>
>
> However, virtio block devide does not have much to do with SCSI (in sense:
> sdparm does not think it is a SCSI device; virtio_blk does not depend on any
> SCSI moduled like sd_mod).
>
> Is "SCSI storage controller" a proper description for this device?
It does not talk SCSI protocol if that's what you're asking. The
description you see comes from the PCI class (storage controller) and
subclass (SCSI controller); the meaning of the class/subclass is fixed
by the PCI standard.
Luca
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
2009-10-19 13:09 ` Luca Tettamanti
@ 2009-10-19 13:31 ` Tomasz Chmielewski
2009-10-19 13:36 ` Luca Tettamanti
2009-10-19 19:01 ` Gerd Hoffmann
0 siblings, 2 replies; 7+ messages in thread
From: Tomasz Chmielewski @ 2009-10-19 13:31 UTC (permalink / raw)
To: Luca Tettamanti; +Cc: kvm, linux-pci
Luca Tettamanti wrote:
> On Mon, Oct 19, 2009 at 2:14 PM, Tomasz Chmielewski <mangoo@wpkg.org> wrote:
>> lspci implies that the virtio block device is a "SCSI storage controller",
>> i.e.:
>>
>> 00:05.0 SCSI storage controller: Qumranet, Inc. Virtio block device
>>
>>
>> However, virtio block devide does not have much to do with SCSI (in sense:
>> sdparm does not think it is a SCSI device; virtio_blk does not depend on any
>> SCSI moduled like sd_mod).
>>
>> Is "SCSI storage controller" a proper description for this device?
>
> It does not talk SCSI protocol if that's what you're asking. The
> description you see comes from the PCI class (storage controller) and
> subclass (SCSI controller); the meaning of the class/subclass is fixed
> by the PCI standard.
So why was "SCSI storage controller" any better than "IDE interface" or
"SATA controller" for virtio block device, if it does not talk SCSI
protocol (other than "SCSI storage controller" being the first on the
list of subclasses)?
Doesn't "80 Mass storage controller" ("0x80 0x00 Other mass storage
controller") fit better for virtio block device?
Generally, I see that 0x80 is reserved for "other/unspecified" types of
devices from a given PCI class.
Let me know if I'm asking a stupid question ;)
C 01 Mass storage controller
00 SCSI storage controller
01 IDE interface
02 Floppy disk controller
03 IPI bus controller
04 RAID bus controller
05 ATA controller
20 ADMA single stepping
30 ADMA continuous operation
06 SATA controller
00 Vendor specific
01 AHCI 1.0
07 Serial Attached SCSI controller
80 Mass storage controller
--
Tomasz Chmielewski
http://wpkg.org
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
2009-10-19 13:31 ` Tomasz Chmielewski
@ 2009-10-19 13:36 ` Luca Tettamanti
2009-10-19 13:42 ` Tomasz Chmielewski
2009-10-19 19:01 ` Gerd Hoffmann
1 sibling, 1 reply; 7+ messages in thread
From: Luca Tettamanti @ 2009-10-19 13:36 UTC (permalink / raw)
To: Tomasz Chmielewski; +Cc: kvm, linux-pci
On Mon, Oct 19, 2009 at 3:31 PM, Tomasz Chmielewski <mangoo@wpkg.org> wrote:
> Luca Tettamanti wrote:
>>
>> On Mon, Oct 19, 2009 at 2:14 PM, Tomasz Chmielewski <mangoo@wpkg.org>
>> wrote:
>>>
>>> lspci implies that the virtio block device is a "SCSI storage
>>> controller",
>>> i.e.:
>>>
>>> 00:05.0 SCSI storage controller: Qumranet, Inc. Virtio block device
>>>
>>>
>>> However, virtio block devide does not have much to do with SCSI (in
>>> sense:
>>> sdparm does not think it is a SCSI device; virtio_blk does not depend on
>>> any
>>> SCSI moduled like sd_mod).
>>>
>>> Is "SCSI storage controller" a proper description for this device?
>>
>> It does not talk SCSI protocol if that's what you're asking. The
>> description you see comes from the PCI class (storage controller) and
>> subclass (SCSI controller); the meaning of the class/subclass is fixed
>> by the PCI standard.
>
> So why was "SCSI storage controller" any better than "IDE interface" or
> "SATA controller" for virtio block device, if it does not talk SCSI protocol
> (other than "SCSI storage controller" being the first on the list of
> subclasses)?
Because both ATA and SATA classes have a generic driver that would try
to bind to that controller (and the whole point of virtio block device
is to avoid emulating a ATA/SATA controller).
> Doesn't "80 Mass storage controller" ("0x80 0x00 Other mass storage
> controller") fit better for virtio block device?
Maybe. I guess that are compatibility problem with "other" operating systems.
Luca
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
2009-10-19 13:36 ` Luca Tettamanti
@ 2009-10-19 13:42 ` Tomasz Chmielewski
2009-10-19 13:48 ` Vadim Rozenfeld
0 siblings, 1 reply; 7+ messages in thread
From: Tomasz Chmielewski @ 2009-10-19 13:42 UTC (permalink / raw)
To: Luca Tettamanti; +Cc: kvm, linux-pci
Luca Tettamanti wrote:
>> So why was "SCSI storage controller" any better than "IDE interface" or
>> "SATA controller" for virtio block device, if it does not talk SCSI protocol
>> (other than "SCSI storage controller" being the first on the list of
>> subclasses)?
>
> Because both ATA and SATA classes have a generic driver that would try
> to bind to that controller (and the whole point of virtio block device
> is to avoid emulating a ATA/SATA controller).
>
>> Doesn't "80 Mass storage controller" ("0x80 0x00 Other mass storage
>> controller") fit better for virtio block device?
>
> Maybe. I guess that are compatibility problem with "other" operating systems.
Thanks for clarifications.
It makes sense in that case - I don't have any more questions ;)
--
Tomasz Chmielewski
http://wpkg.org
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
2009-10-19 13:42 ` Tomasz Chmielewski
@ 2009-10-19 13:48 ` Vadim Rozenfeld
0 siblings, 0 replies; 7+ messages in thread
From: Vadim Rozenfeld @ 2009-10-19 13:48 UTC (permalink / raw)
To: Tomasz Chmielewski; +Cc: Luca Tettamanti, kvm, linux-pci
On 10/19/2009 03:42 PM, Tomasz Chmielewski wrote:
> Luca Tettamanti wrote:
>
>>> So why was "SCSI storage controller" any better than "IDE interface" or
>>> "SATA controller" for virtio block device, if it does not talk SCSI
>>> protocol
>>> (other than "SCSI storage controller" being the first on the list of
>>> subclasses)?
>>
>> Because both ATA and SATA classes have a generic driver that would try
>> to bind to that controller (and the whole point of virtio block device
>> is to avoid emulating a ATA/SATA controller).
>>
>>> Doesn't "80 Mass storage controller" ("0x80 0x00 Other mass
>>> storage
>>> controller") fit better for virtio block device?
>>
>> Maybe. I guess that are compatibility problem with "other" operating
>> systems.
>
> Thanks for clarifications.
>
> It makes sense in that case - I don't have any more questions ;)
>
>
we need it for windows viostor driver to be WHQL'ed
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really?
2009-10-19 13:31 ` Tomasz Chmielewski
2009-10-19 13:36 ` Luca Tettamanti
@ 2009-10-19 19:01 ` Gerd Hoffmann
1 sibling, 0 replies; 7+ messages in thread
From: Gerd Hoffmann @ 2009-10-19 19:01 UTC (permalink / raw)
To: Tomasz Chmielewski; +Cc: Luca Tettamanti, kvm, linux-pci
> C 01 Mass storage controller
> 00 SCSI storage controller
> 01 IDE interface
> 02 Floppy disk controller
> 03 IPI bus controller
> 04 RAID bus controller
> 05 ATA controller
> 20 ADMA single stepping
> 30 ADMA continuous operation
> 06 SATA controller
> 00 Vendor specific
> 01 AHCI 1.0
> 07 Serial Attached SCSI controller
> 80 Mass storage controller
Virtio used to advertise itself as class 0x0180 aka "mass storage
controller". You can even switch the driver into that mode for backward
compatibility reasons. Problem with that is that you can't get windows
driver certifications then ...
cheers,
Gerd
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2009-10-19 19:01 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2009-10-19 12:14 lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really? Tomasz Chmielewski
2009-10-19 13:09 ` Luca Tettamanti
2009-10-19 13:31 ` Tomasz Chmielewski
2009-10-19 13:36 ` Luca Tettamanti
2009-10-19 13:42 ` Tomasz Chmielewski
2009-10-19 13:48 ` Vadim Rozenfeld
2009-10-19 19:01 ` Gerd Hoffmann
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