[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 3/4] amd-iommu: disable iommu_hap_pt_share with AMD IOMMUs
On 23/04/14 12:51, Jan Beulich wrote: >>>> On 23.04.14 at 12:04, <roger.pau@xxxxxxxxxx> wrote: >> On 23/04/14 11:57, Jan Beulich wrote: >>>>>> On 23.04.14 at 10:16, <roger.pau@xxxxxxxxxx> wrote: >>>> According to the comment in p2m.h, AMD IOMMUs don't work correctly >>>> with page types different than p2m_ram_rw when the p2m is shared >>>> between HAP and IOMMU, so disable this sharing when using AMD IOMMUs. >>> >>> Doesn't this need to go before patch 2? >> >> It could certainly go before patch 2, but I don't see such a hard >> requirement in the ordering (either way AMD hardware needs both patches >> to work correctly, and applying one before the other is not going to >> break bisection AFAICT). > > Patch 2 allows the high bits in present IOMMU entries to be non-zero, > thus allowing for IOMMU faults without this patch already in effect. Since on AMD hardware iommu_hap_pt_share is always true (unless the user forces it to false), the previous patch has no effect without this one (because the previous patch only deals with iommu_hap_pt_share == false). I don't mind moving it anyway, and will do it in the next version. Roger. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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