Hi Oleksandr-san, > From: Oleksandr Tyshchenko, Sent: Wednesday, August 21, 2019 3:10 AM > > From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com> > > The IPMMU-VMSA is VMSA-compatible I/O Memory Management Unit (IOMMU) > which provides address translation and access protection functionalities > to processing units and interconnect networks. > > Please note, current driver is supposed to work only with newest > Gen3 SoCs revisions which IPMMU hardware supports stage 2 translation
This is still "Gen3", so that please replace it with "R-Car Gen3"... > table format and is able to use CPU's P2M table as is if one is > 3-level page table (up to 40 bit IPA). > > The major differences compare to the Linux driver are: > > 1. Stage 1/Stage 2 translation. Linux driver supports Stage 1 > translation only (with Stage 1 translation table format). It manages > page table by itself. But Xen driver supports Stage 2 translation > (with Stage 2 translation table format) to be able to share the P2M > with the CPU. Stage 1 translation is always bypassed in Xen driver. > > So, Xen driver is supposed to be used with newest R-Car Gen3 SoC revisions > only (H3 ES3.0, M3-W+, etc.) which IPMMU H/W supports stage 2 translation > table format. > > 2. AArch64 support. Linux driver uses VMSAv8-32 mode, while Xen driver > enables Armv8 VMSAv8-64 mode to cover up to 40 bit input address. > > 3. Context bank (sets of page table) usage. In Xen, each context bank is > mapped to one Xen domain. So, all devices being pass throughed to the > same Xen domain share the same context bank. > > 4. IPMMU device tracking. In Xen, all IOMMU devices are managed > by single driver instance. So, driver uses global list to keep track > of registered IPMMU devices. > > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com> > CC: Julien Grall <julien.gr...@arm.com> > CC: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com> About this hardware handling, this patch seems good to me. But, since I'm not familiar about Xen passthrough framework, I think I cannot add my Reviewed-by tag into this patch. What do you think? Best regards, Yoshihiro Shimoda _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
