From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: Pe: [PATCH v5 1/3] virtio-scsi: first version Date: Tue, 7 Feb 2012 13:10:41 +0200 Message-ID: <20120207111041.GA6674@redhat.com> References: <4F30F4EE.4080607@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4F30F4EE.4080607@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Paolo Bonzini Cc: Christian Hoff , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, rusty@rustcorp.com.au, kvm@vger.kernel.org List-Id: linux-scsi@vger.kernel.org On Tue, Feb 07, 2012 at 10:54:54AM +0100, Paolo Bonzini wrote: > >Also, lun[1] = sc->device->id means that only 255 SCSI target IDs will be > >supported. Think about bigger usage scenarios, such as FCP networks with > >several hundred HBAs in the net. If you want to have the target ID<->HBA > >mapping the same as on the guest as on the host, then 255 virtual target > >IDs could be a limit. > > I think you would hit other scalability limitations well before > that. I plan to give each target its own MSI-X interrupt, but there > is no infinite supplies of those either. virtio-pci generally lets guests share MSI-X vectors between queues, why not allow this here? -- MST