[v10,07/10] memory: Add interface to set iommu page size mask

From: Bharat Bhushan <bbhushan2@marvell.com>

Allow to set the page size mask supported by an iommu memory region.
This enables a vIOMMU to communicate the page size granule supported by
an assigned device, on hosts that use page sizes greater than 4kB.

Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
v10: Add errp parameter
---
 include/exec/memory.h | 26 ++++++++++++++++++++++++++
 softmmu/memory.c      | 13 +++++++++++++
 2 files changed, 39 insertions(+)

Hi Jean,

On 10/8/20 7:15 PM, Jean-Philippe Brucker wrote:
> From: Bharat Bhushan <bbhushan2@marvell.com>
> 
> Allow to set the page size mask supported by an iommu memory region.
> This enables a vIOMMU to communicate the page size granule supported by
> an assigned device, on hosts that use page sizes greater than 4kB.
> 
> Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
> v10: Add errp parameter
> ---
>  include/exec/memory.h | 26 ++++++++++++++++++++++++++
>  softmmu/memory.c      | 13 +++++++++++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index dee09851622..c2da8381bec 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -382,6 +382,20 @@ struct IOMMUMemoryRegionClass {
>       * @iommu: the IOMMUMemoryRegion
>       */
>      int (*num_indexes)(IOMMUMemoryRegion *iommu);
> +
> +    /*
> +     * Set supported IOMMU page size
> +     *
> +     * If supported, allows to restrict the page size mask that can be supported
To match other docs: Optional method:
> +     * with a given IOMMU memory region. For example, to propagate host physical
> +     * IOMMU page size mask limitations to the virtual IOMMU.
> +     *
> +     * Returns 0 on success, or a negative error. In case of failure, the error
> +     * object must be created.
document args as done for other functions?
> +     */
> +     int (*iommu_set_page_size_mask)(IOMMUMemoryRegion *iommu,
> +                                     uint64_t page_size_mask,
> +                                     Error **errp);
>  };
>  
>  typedef struct CoalescedMemoryRange CoalescedMemoryRange;
> @@ -1389,6 +1403,18 @@ int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
>   */
>  int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr);
>  
> +/**
> + * memory_region_iommu_set_page_size_mask: set the supported page
> + * sizes for a given IOMMU memory region
> + *
> + * @iommu_mr: IOMMU memory region
> + * @page_size_mask: supported page size mask
> + * @errp: pointer to Error*, to store an error if it happens.
> + */
> +int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
> +                                           uint64_t page_size_mask,
> +                                           Error **errp);
> +
>  /**
>   * memory_region_name: get a memory region's name
>   *
> diff --git a/softmmu/memory.c b/softmmu/memory.c
> index fa280a19f7f..5c855a02704 100644
> --- a/softmmu/memory.c
> +++ b/softmmu/memory.c
> @@ -1811,6 +1811,19 @@ static int memory_region_update_iommu_notify_flags(IOMMUMemoryRegion *iommu_mr,
>      return ret;
>  }
>  
> +int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
> +                                           uint64_t page_size_mask,
> +                                           Error **errp)
> +{
> +    IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
> +    int ret = 0;
> +
> +    if (imrc->iommu_set_page_size_mask) {
> +        ret = imrc->iommu_set_page_size_mask(iommu_mr, page_size_mask, errp);
> +    }
> +    return ret;
> +}
> +
>  int memory_region_register_iommu_notifier(MemoryRegion *mr,
>                                            IOMMUNotifier *n, Error **errp)
>  {
> 
Besides

Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric

On Thu, Oct 08, 2020 at 07:15:55PM +0200, Jean-Philippe Brucker wrote:
> From: Bharat Bhushan <bbhushan2@marvell.com>
> 
> Allow to set the page size mask supported by an iommu memory region.
> This enables a vIOMMU to communicate the page size granule supported by
> an assigned device, on hosts that use page sizes greater than 4kB.
> 
> Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

Acked-by: Peter Xu <peterx@redhat.com>

On Fri, Oct 16, 2020 at 11:24:08AM +0200, Auger Eric wrote:
> > +    /*
> > +     * Set supported IOMMU page size
> > +     *
> > +     * If supported, allows to restrict the page size mask that can be supported
> To match other docs: Optional method:
> > +     * with a given IOMMU memory region. For example, to propagate host physical
> > +     * IOMMU page size mask limitations to the virtual IOMMU.
> > +     *
> > +     * Returns 0 on success, or a negative error. In case of failure, the error
> > +     * object must be created.
> document args as done for other functions?

I'll change this comment to:

    /**
     * @iommu_set_page_size_mask:
     *
     * Restrict the page size mask that can be supported with a given IOMMU
     * memory region. Used for example to propagate host physical IOMMU page
     * size mask limitations to the virtual IOMMU.
     *
     * Optional method: if this method is not provided, then the default global
     * page mask is used.
     *
     * @iommu: the IOMMUMemoryRegion
     *
     * @page_size_mask: a bitmask of supported page sizes. At least one bit,
     * representing the smallest page size, must be set. Additional set bits
     * represent supported block sizes. For example a host physical IOMMU that
     * uses page tables with a page size of 4kB, and supports 2MB and 4GB
     * blocks, will set mask 0x40201000. A granule of 4kB with indiscriminate
     * block sizes is specified with mask 0xfffffffffffff000.
     *
     * Returns 0 on success, or a negative error. In case of failure, the error
     * object must be created.
     */

Thanks,
Jean