From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: lspci says: "SCSI storage controller: Qumranet, Inc. Virtio block device". Is it really? Date: Mon, 19 Oct 2009 15:31:17 +0200 Message-ID: <4ADC6A25.5080503@wpkg.org> References: <4ADC582E.305@wpkg.org> <68676e00910190609t5dee17e9y9f26b63b7a077de3@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, linux-pci@vger.kernel.org To: Luca Tettamanti Return-path: In-Reply-To: <68676e00910190609t5dee17e9y9f26b63b7a077de3@mail.gmail.com> Sender: linux-pci-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Luca Tettamanti wrote: > On Mon, Oct 19, 2009 at 2:14 PM, Tomasz Chmielewski 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