> -----Original Message----- > From: Joerg Roedel [mailto:joro@xxxxxxxxxx] > Sent: 18 May 2021 09:50 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; Linuxarm <linuxarm@xxxxxxxxxx>; > lorenzo.pieralisi@xxxxxxx; robin.murphy@xxxxxxx; wanghuiqiang > <wanghuiqiang@xxxxxxxxxx>; Guohanjun (Hanjun Guo) > <guohanjun@xxxxxxxxxx>; steven.price@xxxxxxx; Sami.Mujawar@xxxxxxx; > jon@xxxxxxxxxxxxx; eric.auger@xxxxxxxxxx; yangyicong > <yangyicong@xxxxxxxxxx> > Subject: Re: [PATCH v4 2/8] iommu/dma: Introduce generic helper to retrieve > RMR info > > On Thu, May 13, 2021 at 02:45:44PM +0100, Shameer Kolothum wrote: > > +/** > > + * struct iommu_rmr - Reserved Memory Region details per IOMMU > > + * @list: Linked list pointers to hold RMR region info > > + * @base_address: base address of Reserved Memory Region > > + * @length: length of memory region > > + * @sid: associated stream id > > + * @flags: flags that apply to the RMR node > > + */ > > +struct iommu_rmr { > > + struct list_head list; > > + phys_addr_t base_address; > > + u64 length; > > + u32 sid; > > + u32 flags; > > +}; > > + > > +/* RMR Remap permitted */ > > +#define IOMMU_RMR_REMAP_PERMITTED (1 << 0) > > + > > This struct has lots of overlap with 'struct iommu_resv_region'. Any > reason the existing struct can't be used here? > Hmm..main reason is "sid". RMRs are associated with stream ids and that is used to install bypass STEs/SMRs in SMMU drivers and also to check whether a dev has any RMR regions associated with it. I think we could add sid/dev_id to 'struct iommu_resv_region', and modify iommu_alloc_resv_region() accordingly. That can get rid of the above struct and iommu_dma_alloc_rmr() fn. Not sure this will complicate things as the dev_id is only valid for RMR reservation region cases. Please let me know your thoughts. Thanks, Shameer
