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Re: [Qemu-arm] [PATCH v2 01/13] iommu: Add IOMMU index concept to IOMMU
From: |
Alex Bennée |
Subject: |
Re: [Qemu-arm] [PATCH v2 01/13] iommu: Add IOMMU index concept to IOMMU API |
Date: |
Thu, 14 Jun 2018 19:21:29 +0100 |
User-agent: |
mu4e 1.1.0; emacs 26.1.50 |
Peter Maydell <address@hidden> writes:
> If an IOMMU supports mappings that care about the memory
> transaction attributes, then it no longer has a unique
> address -> output mapping, but more than one. We can
> represent these using an IOMMU index, analogous to TCG's
> mmu indexes.
>
> Signed-off-by: Peter Maydell <address@hidden>
> Reviewed-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
> ---
> include/exec/memory.h | 55 +++++++++++++++++++++++++++++++++++++++++++
> memory.c | 23 ++++++++++++++++++
> 2 files changed, 78 insertions(+)
>
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index eb2ba065195..fa6e98ee7be 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -206,6 +206,20 @@ enum IOMMUMemoryRegionAttr {
> * to report whenever mappings are changed, by calling
> * memory_region_notify_iommu() (or, if necessary, by calling
> * memory_region_notify_one() for each registered notifier).
> + *
> + * Conceptually an IOMMU provides a mapping from input address
> + * to an output TLB entry. If the IOMMU is aware of memory transaction
> + * attributes and the output TLB entry depends on the transaction
> + * attributes, we represent this using IOMMU indexes. Each index
> + * selects a particular translation table that the IOMMU has:
> + * @attrs_to_index returns the IOMMU index for a set of transaction
> attributes
> + * @translate takes an input address and an IOMMU index
> + * and the mapping returned can only depend on the input address and the
> + * IOMMU index.
> + *
> + * Most IOMMUs don't care about the transaction attributes and support
> + * only a single IOMMU index. A more complex IOMMU might have one index
> + * for secure transactions and one for non-secure transactions.
> */
> typedef struct IOMMUMemoryRegionClass {
> /* private */
> @@ -290,6 +304,29 @@ typedef struct IOMMUMemoryRegionClass {
> */
> int (*get_attr)(IOMMUMemoryRegion *iommu, enum IOMMUMemoryRegionAttr
> attr,
> void *data);
> +
> + /* Return the IOMMU index to use for a given set of transaction
> attributes.
> + *
> + * Optional method: if an IOMMU only supports a single IOMMU index then
> + * the default implementation of memory_region_iommu_attrs_to_index()
> + * will return 0.
> + *
> + * The indexes supported by an IOMMU must be contiguous, starting at 0.
> + *
> + * @iommu: the IOMMUMemoryRegion
> + * @attrs: memory transaction attributes
> + */
> + int (*attrs_to_index)(IOMMUMemoryRegion *iommu, MemTxAttrs attrs);
> +
> + /* Return the number of IOMMU indexes this IOMMU supports.
> + *
> + * Optional method: if this method is not provided, then
> + * memory_region_iommu_num_indexes() will return 1, indicating that
> + * only a single IOMMU index is supported.
> + *
> + * @iommu: the IOMMUMemoryRegion
> + */
> + int (*num_indexes)(IOMMUMemoryRegion *iommu);
> } IOMMUMemoryRegionClass;
>
> typedef struct CoalescedMemoryRange CoalescedMemoryRange;
> @@ -1054,6 +1091,24 @@ int memory_region_iommu_get_attr(IOMMUMemoryRegion
> *iommu_mr,
> enum IOMMUMemoryRegionAttr attr,
> void *data);
>
> +/**
> + * memory_region_iommu_attrs_to_index: return the IOMMU index to
> + * use for translations with the given memory transaction attributes.
> + *
> + * @iommu_mr: the memory region
> + * @attrs: the memory transaction attributes
> + */
> +int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
> + MemTxAttrs attrs);
> +
> +/**
> + * memory_region_iommu_num_indexes: return the total number of IOMMU
> + * indexes that this IOMMU supports.
> + *
> + * @iommu_mr: the memory region
> + */
> +int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr);
> +
> /**
> * memory_region_name: get a memory region's name
> *
> diff --git a/memory.c b/memory.c
> index 3212acc7f49..64f4a55d546 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1915,6 +1915,29 @@ int memory_region_iommu_get_attr(IOMMUMemoryRegion
> *iommu_mr,
> return imrc->get_attr(iommu_mr, attr, data);
> }
>
> +int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
> + MemTxAttrs attrs)
> +{
> + IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
> +
> + if (!imrc->attrs_to_index) {
> + return 0;
> + }
> +
> + return imrc->attrs_to_index(iommu_mr, attrs);
> +}
> +
> +int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr)
> +{
> + IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
> +
> + if (!imrc->num_indexes) {
> + return 1;
> + }
> +
> + return imrc->num_indexes(iommu_mr);
> +}
> +
> void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client)
> {
> uint8_t mask = 1 << client;
--
Alex Bennée
[Qemu-arm] [PATCH v2 02/13] iommu: Add IOMMU index argument to notifier APIs, Peter Maydell, 2018/06/04
[Qemu-arm] [PATCH v2 04/13] exec.c: Handle IOMMUs in address_space_translate_for_iotlb(), Peter Maydell, 2018/06/04