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Re: [Qemu-devel] [RFC PATCH] pci: Use PCI aliases when determining devic
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From: |
Alex Williamson |
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Subject: |
Re: [Qemu-devel] [RFC PATCH] pci: Use PCI aliases when determining device IOMMU address space |
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Date: |
Thu, 25 Jul 2019 08:00:23 -0600 |
On Thu, 25 Jul 2019 06:43:04 -0400
"Michael S. Tsirkin" <address@hidden> wrote:
> On Thu, Jul 25, 2019 at 02:37:33PM +0800, Peter Xu wrote:
> > After re-read Michael's reply, I feel like what Michael suggested is
> > that we can simply ignore the bus-number-change case by the guest OS
> > for now, but I might be wrong.
> That's what I suggested, yes.
"by the guest OS", yes, that's the part that's beyond the scope of this
effort. If we deem it necessary to support IVHD DMA alias though, it's
the guest firmware that determines the initial bus numbers, which is
part of the DeviceID used to defined IVHD entries and we would not be
able to ignore that initial programming. Everything related to the
guest OS renumber PCI buses is out of scope, the guest firmware
programming initial bus numbers is not. Thanks,
Alex