Re: [PATCH v3 02/16] iommu: Introduce cache_invalidate API

From: Auger Eric
Date: Mon May 13 2019 - 05:16:27 EST

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Hi Jacob, Jean-Philippe,

On 5/4/19 12:32 AM, Jacob Pan wrote:
> From: "Liu, Yi L" <yi.l.liu@xxxxxxxxxxxxxxx>
>
> In any virtualization use case, when the first translation stage
> is "owned" by the guest OS, the host IOMMU driver has no knowledge
> of caching structure updates unless the guest invalidation activities
> are trapped by the virtualizer and passed down to the host.
>
> Since the invalidation data are obtained from user space and will be
> written into physical IOMMU, we must allow security check at various
> layers. Therefore, generic invalidation data format are proposed here,
> model specific IOMMU drivers need to convert them into their own format.
>
> Signed-off-by: Liu, Yi L <yi.l.liu@xxxxxxxxxxxxxxx>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>
> ---
> v6 -> v7:
> - detail which fields are used for each invalidation type
> - add a comment about multiple cache invalidation
>
> v5 -> v6:
> - fix merge issue
>
> v3 -> v4:
> - full reshape of the API following Alex' comments
>
> v1 -> v2:
> - add arch_id field
> - renamed tlb_invalidate into cache_invalidate as this API allows
> to invalidate context caches on top of IOTLBs
>
> v1:
> renamed sva_invalidate into tlb_invalidate and add iommu_ prefix in
> header. Commit message reworded.
> ---
> drivers/iommu/iommu.c | 14 ++++++++
> include/linux/iommu.h | 15 ++++++++-
> include/uapi/linux/iommu.h | 80 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 108 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 8df9d34..a2f6f3e 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1645,6 +1645,20 @@ void iommu_detach_pasid_table(struct iommu_domain *domain)
> }
> EXPORT_SYMBOL_GPL(iommu_detach_pasid_table);
>
> +int iommu_cache_invalidate(struct iommu_domain *domain, struct device *dev,
> + struct iommu_cache_invalidate_info *inv_info)
> +{
> + int ret = 0;
> +
> + if (unlikely(!domain->ops->cache_invalidate))
> + return -ENODEV;
> +
> + ret = domain->ops->cache_invalidate(domain, dev, inv_info);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_cache_invalidate);
> +
> static void __iommu_detach_device(struct iommu_domain *domain,
> struct device *dev)
> {
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index ab4d922..d182525 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -266,6 +266,7 @@ struct page_response_msg {
> * @page_response: handle page request response
> * @attach_pasid_table: attach a pasid table
> * @detach_pasid_table: detach the pasid table
> + * @cache_invalidate: invalidate translation caches
> * @pgsize_bitmap: bitmap of all possible supported page sizes
> */
> struct iommu_ops {
> @@ -328,8 +329,9 @@ struct iommu_ops {
> int (*attach_pasid_table)(struct iommu_domain *domain,
> struct iommu_pasid_table_config *cfg);
> void (*detach_pasid_table)(struct iommu_domain *domain);
> -
> int (*page_response)(struct device *dev, struct page_response_msg *msg);
> + int (*cache_invalidate)(struct iommu_domain *domain, struct device *dev,
> + struct iommu_cache_invalidate_info *inv_info);
>
> unsigned long pgsize_bitmap;
> };
> @@ -442,6 +444,9 @@ extern void iommu_detach_device(struct iommu_domain *domain,
> extern int iommu_attach_pasid_table(struct iommu_domain *domain,
> struct iommu_pasid_table_config *cfg);
> extern void iommu_detach_pasid_table(struct iommu_domain *domain);
> +extern int iommu_cache_invalidate(struct iommu_domain *domain,
> + struct device *dev,
> + struct iommu_cache_invalidate_info *inv_info);
> extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
> extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
> extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
> @@ -982,6 +987,14 @@ static inline int iommu_sva_get_pasid(struct iommu_sva *handle)
> static inline
> void iommu_detach_pasid_table(struct iommu_domain *domain) {}
>
> +static inline int
> +iommu_cache_invalidate(struct iommu_domain *domain,
> + struct device *dev,
> + struct iommu_cache_invalidate_info *inv_info)
> +{
> + return -ENODEV;
> +}
> +
> #endif /* CONFIG_IOMMU_API */
>
> #ifdef CONFIG_IOMMU_DEBUGFS
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> index 8848514..fa96ecb 100644
> --- a/include/uapi/linux/iommu.h
> +++ b/include/uapi/linux/iommu.h
> @@ -162,4 +162,84 @@ struct iommu_pasid_table_config {
> };
> };

I noticed my qemu integration was currently incorrectly using PASID
invalidation for ASID based invalidation (SMMUV3 Stage1 CMD_TLBI_NH_ASID
invalidation command). So I think we also need ARCHID invalidation.
Sorry for the late notice.
>
> +/* defines the granularity of the invalidation */
> +enum iommu_inv_granularity {
> + IOMMU_INV_GRANU_DOMAIN, /* domain-selective invalidation */
IOMMU_INV_GRANU_ARCHID, /* archid-selective invalidation */
> + IOMMU_INV_GRANU_PASID, /* pasid-selective invalidation */
> + IOMMU_INV_GRANU_ADDR, /* page-selective invalidation */
> + IOMMU_INVAL_GRANU_NR, /* number of invalidation granularities */
> +};
> +
> +/**
> + * Address Selective Invalidation Structure
> + *
> + * @flags indicates the granularity of the address-selective invalidation
> + * - if PASID bit is set, @pasid field is populated and the invalidation
> + * relates to cache entries tagged with this PASID and matching the
> + * address range.
> + * - if ARCHID bit is set, @archid is populated and the invalidation relates
> + * to cache entries tagged with this architecture specific id and matching
> + * the address range.
> + * - Both PASID and ARCHID can be set as they may tag different caches.
> + * - if neither PASID or ARCHID is set, global addr invalidation applies
> + * - LEAF flag indicates whether only the leaf PTE caching needs to be
> + * invalidated and other paging structure caches can be preserved.
> + * @pasid: process address space id
> + * @archid: architecture-specific id
> + * @addr: first stage/level input address
> + * @granule_size: page/block size of the mapping in bytes
> + * @nb_granules: number of contiguous granules to be invalidated
> + */
> +struct iommu_inv_addr_info {
> +#define IOMMU_INV_ADDR_FLAGS_PASID (1 << 0)
> +#define IOMMU_INV_ADDR_FLAGS_ARCHID (1 << 1)
> +#define IOMMU_INV_ADDR_FLAGS_LEAF (1 << 2)
> + __u32 flags;
> + __u32 archid;
> + __u64 pasid;
> + __u64 addr;
> + __u64 granule_size;
> + __u64 nb_granules;
> +};
> +
> +/**
> + * First level/stage invalidation information
> + * @cache: bitfield that allows to select which caches to invalidate
> + * @granularity: defines the lowest granularity used for the invalidation:
> + * domain > pasid > addr
> + *
> + * Not all the combinations of cache/granularity make sense:
> + *
> + * type | DEV_IOTLB | IOTLB | PASID |
> + * granularity | | | cache |
> + * -------------+---------------+---------------+---------------+
> + * DOMAIN | N/A | Y | Y |
* ARCHID | N/A | Y | N/A |

> + * PASID | Y | Y | Y |
> + * ADDR | Y | Y | N/A |
> + *
> + * Invalidations by %IOMMU_INV_GRANU_ADDR use field @addr_info.
* Invalidations by %IOMMU_INV_GRANU_ARCHID use field @archid.
> + * Invalidations by %IOMMU_INV_GRANU_PASID use field @pasid.
> + * Invalidations by %IOMMU_INV_GRANU_DOMAIN don't take any argument.
> + *
> + * If multiple cache types are invalidated simultaneously, they all
> + * must support the used granularity.
> + */
> +struct iommu_cache_invalidate_info {
> +#define IOMMU_CACHE_INVALIDATE_INFO_VERSION_1 1
> + __u32 version;
> +/* IOMMU paging structure cache */
> +#define IOMMU_CACHE_INV_TYPE_IOTLB (1 << 0) /* IOMMU IOTLB */
> +#define IOMMU_CACHE_INV_TYPE_DEV_IOTLB (1 << 1) /* Device IOTLB */
> +#define IOMMU_CACHE_INV_TYPE_PASID (1 << 2) /* PASID cache */
> +#define IOMMU_CACHE_TYPE_NR (3)
> + __u8 cache;
> + __u8 granularity;
> + __u8 padding[2];
> + union {
> + __u64 pasid;
__u32 archid;

Thanks

Eric
> + struct iommu_inv_addr_info addr_info;
> + };
> +};
> +
> +
> #endif /* _UAPI_IOMMU_H */
>

Next message: Yuyang Du: "[PATCH 03/17] locking/lockdep: Add helper functions to operate on the searched path"
Previous message: Fabien DESSENNE: "Re: [PATCH v2 0/6] hwspinlock: allow sharing of hwspinlocks"
Next in thread: Jean-Philippe Brucker: "Re: [PATCH v3 02/16] iommu: Introduce cache_invalidate API"
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