[PATCH v4 5/7] iommu/io-pgtable-arm: Add read_and_clear_dirty() support

[Jason Gunthorpe]

On Tue, May 28, 2024 at 08:18:29AM +0100, Shameer Kolothum wrote:
> .read_and_clear_dirty() IOMMU domain op takes care of reading the dirty
> bits (i.e. PTE has DBM set and AP[2] clear) and marshalling into a
> bitmap of a given page size.
> 
> While reading the dirty bits we also set the PTE AP[2] bit to mark it
> as writeable-clean depending on read_and_clear_dirty() flags.
> 
> PTE states with respect to DBM bit:
> 
>                        DBM bit        AP[2]("RDONLY" bit)
> 1. writable_clean        1                 1
> 2. writable_dirty        1                 0
> 3. read-only             0                 1
> 
> Reviewed-by: Ryan Roberts <ryan.roberts at arm.com>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
> ---
>  drivers/iommu/io-pgtable-arm.c | 114 ++++++++++++++++++++++++++++++++-
>  1 file changed, 112 insertions(+), 2 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>

Jason