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Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture
From: |
Gerd Hoffmann |
Subject: |
Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture |
Date: |
Wed, 17 Jun 2020 12:12:33 +0200 |
On Wed, Jun 17, 2020 at 10:16:55AM +0200, Christophe de Dinechin wrote:
>
>
> > Le 16 Jun 2020 à 18:50, Gerd Hoffmann <kraxel@redhat.com> a écrit :
> >
> > Hi,
> >
> >> (a) We could rely in the guest physbits to calculate the PCI64 aperture.
> >
> > I'd love to do that. Move the 64-bit I/O window as high as possible and
> > use -- say -- 25% of the physical address space for it.
> >
> > Problem is we can't.
>
> Is the only reason unreliable guest physbits?
Yes.
> > If we can somehow make a *trustable* physbits value available to the
> > guest, then yes, we can go that route. But the guest physbits we have
> > today unfortunately don't cut it.
>
> What is the rationale for ever allowing guest physbits > host physbits?
I can't think of a good reason. So probably simply historical reasons
and the fact that this isn't a problem with tcg.
take care,
Gerd Hoffmann
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, (continued)
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Eduardo Habkost, 2020/06/17
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Dr. David Alan Gilbert, 2020/06/19
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Laszlo Ersek, 2020/06/17
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Laszlo Ersek, 2020/06/17
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Eduardo Habkost, 2020/06/17
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Laszlo Ersek, 2020/06/18
Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture, Christophe de Dinechin, 2020/06/17
- Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture,
Gerd Hoffmann <=