On 2014/11/26 1:27, Robin Murphy wrote:
> Systems may contain heterogeneous IOMMUs supporting differing minimum
> page sizes, which may also not be common with the CPU page size.
> Thus it is practical to have an explicit notion of IOVA granularity
> to simplify handling of mapping and allocation constraints.
>
> As an initial step, move the IOVA page granularity from an implicit
> compile-time constant to a per-domain property so we can make use
> of it in IOVA domain context at runtime. To keep the abstraction tidy,
> extend the little API of inline iova_* helpers to parallel some of the
> equivalent PAGE_* macros.
>
> Signed-off-by: Robin Murphy <robin.mur...@arm.com>
> ---
> drivers/iommu/intel-iommu.c | 9 ++++++---
> drivers/iommu/iova.c | 8 ++++++--
> include/linux/iova.h | 35 +++++++++++++++++++++++++++++++++--
> 3 files changed, 45 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index daba0c2..d4cf6f0 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -1632,7 +1632,8 @@ static int dmar_init_reserved_ranges(void)
> struct iova *iova;
> int i;
>
> - init_iova_domain(&reserved_iova_list, IOVA_START_PFN, DMA_32BIT_PFN);
> + init_iova_domain(&reserved_iova_list, VTD_PAGE_SIZE, IOVA_START_PFN,
> + DMA_32BIT_PFN);
>
> lockdep_set_class(&reserved_iova_list.iova_rbtree_lock,
> &reserved_rbtree_key);
> @@ -1690,7 +1691,8 @@ static int domain_init(struct dmar_domain *domain, int
> guest_width)
> int adjust_width, agaw;
> unsigned long sagaw;
>
> - init_iova_domain(&domain->iovad, IOVA_START_PFN, DMA_32BIT_PFN);
> + init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN,
> + DMA_32BIT_PFN);
> domain_reserve_special_ranges(domain);
>
> /* calculate AGAW */
> @@ -4163,7 +4165,8 @@ static int md_domain_init(struct dmar_domain *domain,
> int guest_width)
> {
> int adjust_width;
>
> - init_iova_domain(&domain->iovad, IOVA_START_PFN, DMA_32BIT_PFN);
> + init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN,
> + DMA_32BIT_PFN);
> domain_reserve_special_ranges(domain);
>
> /* calculate AGAW */
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
> index a3dbba8..9e50625 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -55,12 +55,16 @@ void free_iova_mem(struct iova *iova)
> }
>
> void
> -init_iova_domain(struct iova_domain *iovad, unsigned long start_pfn,
> - unsigned long pfn_32bit)
> +init_iova_domain(struct iova_domain *iovad, unsigned long granule,
> + unsigned long start_pfn, unsigned long pfn_32bit)
> {
> + /* IOMMUs must support at least the CPU page size */
> + BUG_ON(granule > PAGE_SIZE);
??? BUG_ON(granule < PAGE_SIZE);
> +
> spin_lock_init(&iovad->iova_rbtree_lock);
> iovad->rbroot = RB_ROOT;
> iovad->cached32_node = NULL;
> + iovad->granule = granule;
Do you need to check granule is 2^n ?
> iovad->start_pfn = start_pfn;
> iovad->dma_32bit_pfn = pfn_32bit;
> }
> diff --git a/include/linux/iova.h b/include/linux/iova.h
> index 591b196..3920a19 100644
> --- a/include/linux/iova.h
> +++ b/include/linux/iova.h
> @@ -28,6 +28,7 @@ struct iova_domain {
> spinlock_t iova_rbtree_lock; /* Lock to protect update of rbtree */
> struct rb_root rbroot; /* iova domain rbtree root */
> struct rb_node *cached32_node; /* Save last alloced node */
> + unsigned long granule; /* pfn granularity for this domain */
> unsigned long start_pfn; /* Lower limit for this domain */
> unsigned long dma_32bit_pfn;
> };
> @@ -37,6 +38,36 @@ static inline unsigned long iova_size(struct iova *iova)
> return iova->pfn_hi - iova->pfn_lo + 1;
> }
>
> +static inline unsigned long iova_shift(struct iova_domain *iovad)
> +{
> + return __ffs(iovad->granule);
I think it's good to save the result to a struct member. If we caculate it
ervertime, it's too slow.
> +}
> +
> +static inline unsigned long iova_mask(struct iova_domain *iovad)
> +{
> + return iovad->granule - 1;
> +}
> +
> +static inline size_t iova_offset(struct iova_domain *iovad, dma_addr_t iova)
> +{
> + return iova & iova_mask(iovad);
> +}
> +
> +static inline size_t iova_align(struct iova_domain *iovad, size_t size)
> +{
> + return ALIGN(size, iovad->granule);
> +}
> +
> +static inline dma_addr_t iova_dma_addr(struct iova_domain *iovad, struct
> iova *iova)
> +{
> + return (dma_addr_t)iova->pfn_lo << iova_shift(iovad);
> +}
> +
> +static inline unsigned long iova_pfn(struct iova_domain *iovad, dma_addr_t
> iova)
> +{
> + return iova >> iova_shift(iovad);
> +}
> +
> int iommu_iova_cache_init(void);
> void iommu_iova_cache_destroy(void);
>
> @@ -50,8 +81,8 @@ struct iova *alloc_iova(struct iova_domain *iovad, unsigned
> long size,
> struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
> unsigned long pfn_hi);
> void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to);
> -void init_iova_domain(struct iova_domain *iovad, unsigned long start_pfn,
> - unsigned long pfn_32bit);
> +void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
> + unsigned long start_pfn, unsigned long pfn_32bit);
> struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
> void put_iova_domain(struct iova_domain *iovad);
> struct iova *split_and_remove_iova(struct iova_domain *iovad,
>
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