Messages in this thread | | | Date | Wed, 3 Mar 2010 17:14:28 +0100 | From | Bastian Blank <> | Subject | Re: [Xen-devel] [PATCH 4 of 4] Linux pvops: xen pci platform device driver |
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On Wed, Mar 03, 2010 at 03:52:07PM +0000, Stefano Stabellini wrote: > On Wed, 3 Mar 2010, Bastian Blank wrote: > > Why is version 1 grant table the default on HVM? > Because version 2 is known not to work on HVM, fixing this is on my TODO > list.
Well, then the later modification to 2 in the hvm case is bogus.
> > > +/* NB. [aux-]ide-disks options do not unplug IDE CD-ROM drives. */ > > > +/* NB. aux-ide-disks is equiv to ide-disks except ignores primary master. */ > > > +static char *dev_unplug; > > > +module_param(dev_unplug, charp, 0644); > > > +MODULE_PARM_DESC(dev_unplug, "Emulated devices to unplug: " > > > + "[all,][ide-disks,][aux-ide-disks,][nics]\n"); > > > > What is this parameter about? > > During the initialization of the xen pci device driver, we write to a > magic ioport that causes qemu to unplug some emulated devices, disc and > network in particular. > This parameter is meant to present the user a choice about what emulated > devices to unplug.
Somehow I don't think this belongs here. It looks like a workaround, you can always ask qemu to not bind them at the beginning and the guest system to not provide drivers.
> > > +#define XEN_IOPORT_BASE 0x10 > > > > Why are this constants defined in the driver themself? They only make > > sense if there are two components making use of them. > Yep, the other one is qemu.
Well, if it is a published interface move it into a header file.
> > > + if (request_mem_region(mmio_addr, mmio_len, DRV_NAME) == NULL) { > > > + printk(KERN_ERR ":MEM I/O resource 0x%lx @ 0x%lx busy\n", > > > + mmio_addr, mmio_len); > > > + return -EBUSY; > > > > Why is this a sign of busy? > > I think we were just trying to follow the behaviour of the other drivers > of real pci devices. > I am not sure how this condition could happen on Xen.
I checked again. There are many different return values used, but EBUSY seems to be the most.
Bastian
-- The heart is not a logical organ. -- Dr. Janet Wallace, "The Deadly Years", stardate 3479.4
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