Re: [Xen-devel] [PATCH 1/3] iommu: set correct IOMMU entries when iommu_hap_pt_share == 0

[Tim Deegan <tim@xxxxxxx>]

At 09:30 +0100 on 08 Apr (1396945844), Jan Beulich wrote:
> >>> On 07.04.14 at 18:02, <roger.pau@xxxxxxxxxx> wrote:
> > If the memory map is not shared between HAP and IOMMU we fails to set
> > correct IOMMU mappings for memory types different than p2m_ram_rw.
> > 
> > This patchs adds IOMMU support for the following memory types:
> > p2m_grant_map_rw, p2m_map_foreign, p2m_ram_ro and p2m_grant_map_ro.
> 
> I'm curious about the justification for p2m_map_foreign; the others
> I agree with.
> 
> I also wonder whether p2m_ram_logdirty shouldn't be treated
> equally to p2m_ram_rw: It's clearly better to have some video
> corruption than to kill the guest due to excessive IOMMU faults,

Hmmm.  In that case it seems better; if we're absolutely sure that we
can't end up trying to do log-dirty for _migration_ while a guest has
a real device passed through, then yes, we can leave them as r/w to
the IOMMU. 

Maybe make sure at the same time that full log-dirty mode and
needs_iommu are mutually exclusive.

Tim.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel