Re: [Xen-devel] Dom0 hypercall for adding and removing PCI devices

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 23/7/08 10:04, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:

> 1) Add a check in domain_context_unmap_one(), don't remove the device
> from dom0 if it has RMRR. This check is added yesterday. But it's not
> clean enough. The device is not assigned to dom0, while it is mapped in
> dom0 VT-d page table.
> 
> 2) Establish a separate RMRR page table. If the device with RMRR is
> removed from dom0, unmap it from dom0 VT-d page table, instead map it to
> the separate RMRR page table. This solution is clean, but it introduces
> a new VT-d page table. Currently each domain has only one VT-d page
> table.
> 
> What's your opinions?

So this would be one extra VT-d pagetable, for the whole system, which would
be the fallback location for RMRR mappings for devices which are currently
not assigned to any domain? Thus allowing firmware to successfully initiate
DMA operations on those devices? Sounds sensible.

 -- Keir



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