[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/3] iommu: set correct IOMMU entries when iommu_hap_pt_share == 0
At 17:15 +0200 on 08 Apr (1396973715), Roger Pau Monné wrote: > On 08/04/14 16:12, Tim Deegan wrote: > > 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. > > Would it suffice to add something like: > > case p2m_ram_logdirty: > ASSERT(!paging_mode_log_dirty(p2m->domain)); > > Or are you referring to a more global check? I was thinking that the paths that _set_ full log-dirty mode or needs_iommu should explicitly test that the other isn't the case (i.e. a logdirty-enable hypercall or assigning a passthough device should fail). Tim. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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