Messages in this thread | | | Subject | Re: [PATCH] SCSI driver for VMware's virtual HBA. | From | James Bottomley <> | Date | Tue, 01 Sep 2009 09:23:32 -0500 |
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On Mon, 2009-08-31 at 14:53 -0700, Alok Kataria wrote: > Hi James, > > Thanks for your comments. > > On Mon, 2009-08-31 at 11:00 -0700, James Bottomley wrote: > > On Mon, 2009-08-31 at 10:28 -0700, Alok Kataria wrote: > > > VMware PVSCSI driver - v2. > > > > OK, so the first thing that springs to mind is that we already have one > > of these things: the ibmvscsi ... is there no way we can share code > > between this and the other PV drivers? > > I took a quick look at the ibmvscsi driver, and there are lot of > differences between the two, mainly the ABI that is shared between the > hypervisor and driver differ.
Well, that's pretty abstractable, surely? However, there is an interesting question of what the best hypervisor interface actually is.
> Also the ibmvscsi driver seems to offer a > lot of other features as well, like the SRP.
SRP is the protocol transfer abstraction. It's just a way of packaging up SCSI commands for transfer over a DMA protocol (OK, so it was envisaged that the DMA protocol would be RDMA, but a hypervisor interface is also a DMA protocol).
> The pvscsi driver is a simple SCSI adapter driver and is basically no > different than any other SCSI driver written for a particular HBA.
Well, it is really ... hopefully all the hypervisor interfaces won't decide to be completely incompatible, so there's a good chance of code sharing between them.
James
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