Re: [PATCH] kvm tools: adds a PCI device that exports a host shared segment as a PCI BAR in the guest

[Sasha Levin <levinsasha928@gmail.com>]

On Thu, 2011-08-25 at 16:35 -0500, Anthony Liguori wrote:
> On 08/24/2011 05:25 PM, David Evensky wrote:
> >
> >
> > This patch adds a PCI device that provides PCI device memory to the
> > guest. This memory in the guest exists as a shared memory segment in
> > the host. This is similar memory sharing capability of Nahanni
> > (ivshmem) available in QEMU. In this case, the shared memory segment
> > is exposed as a PCI BAR only.
> >
> > A new command line argument is added as:
> >      --shmem pci:0xc8000000:16MB:handle=/newmem:create
> >
> > diff -uprN -X linux-kvm/Documentation/dontdiff linux-kvm/tools/kvm/include/kvm/pci-shmem.h linux-kvm_pci_shmem/tools/kvm/include/kvm/pci-shmem.h
> > --- linux-kvm/tools/kvm/include/kvm/pci-shmem.h	1969-12-31 16:00:00.000000000 -0800
> > +++ linux-kvm_pci_shmem/tools/kvm/include/kvm/pci-shmem.h	2011-08-13 15:43:01.067953711 -0700
> > @@ -0,0 +1,13 @@
> > +#ifndef KVM__PCI_SHMEM_H
> > +#define KVM__PCI_SHMEM_H
> > +
> > +#include<linux/types.h>
> > +#include<linux/list.h>
> > +
> > +struct kvm;
> > +struct shmem_info;
> > +
> > +int pci_shmem__init(struct kvm *self);
> > +int pci_shmem__register_mem(struct shmem_info *si);
> > +
> > +#endif
> > diff -uprN -X linux-kvm/Documentation/dontdiff linux-kvm/tools/kvm/include/kvm/virtio-pci-dev.h linux-kvm_pci_shmem/tools/kvm/include/kvm/virtio-pci-dev.h
> > --- linux-kvm/tools/kvm/include/kvm/virtio-pci-dev.h	2011-08-09 15:38:48.760120973 -0700
> > +++ linux-kvm_pci_shmem/tools/kvm/include/kvm/virtio-pci-dev.h	2011-08-18 10:06:12.171539230 -0700
> > @@ -15,10 +15,13 @@
> >   #define PCI_DEVICE_ID_VIRTIO_BLN		0x1005
> >   #define PCI_DEVICE_ID_VIRTIO_P9			0x1009
> >   #define PCI_DEVICE_ID_VESA			0x2000
> > +#define PCI_DEVICE_ID_PCI_SHMEM			0x0001
> >
> >   #define PCI_VENDOR_ID_REDHAT_QUMRANET		0x1af4
> > +#define PCI_VENDOR_ID_PCI_SHMEM			0x0001
> >   #define PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET	0x1af4
> 
> FYI, that's not a valid vendor and device ID.
> 
> Perhaps the RH folks would be willing to reserve a portion of the device 
> ID space in their vendor ID for ya'll to play around with.

I'm working on a patch on top of David's patch to turn it into a ivshmem
device. Once it's ready we would use same vendor/device IDs.

-- 

Sasha.