Re: [PATCH v2 3/4] xen/arm: introduce GNTTABOP_cache_flush

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 03/10/14 17:33, Stefano Stabellini wrote:
> On Fri, 3 Oct 2014, Andrew Cooper wrote:
>> On 03/10/14 15:50, Stefano Stabellini wrote:
>>> Introduce a new hypercall to perform cache maintenance operation on
>>> behalf of the guest. The argument is a machine address and a size. The
>>> implementation checks that the memory range is owned by the guest or the
>>> guest has been granted access to it by another domain.
>>>
>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>>>
>>> ---
>>>
>>> Changes in v2:
>>> - do not check for mfn_to_page errors;
>>> - take a reference to the page;
>>> - replace printk with gdprintk;
>>> - split long line;
>>> - remove out label;
>>> - move rcu_lock_current_domain down before the loop.
>>> - move the hypercall to GNTTABOP;
>>> - take a spin_lock before calling grant_map_exists.
>>> ---
>>>  xen/common/grant_table.c         |   73 ++++++++++++++++++++++++++++++++++++++
>>>  xen/include/public/grant_table.h |   19 ++++++++++
>>>  2 files changed, 92 insertions(+)
>>>
>>> diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
>>> index 7a6399b..d5bb4f7 100644
>>> --- a/xen/common/grant_table.c
>>> +++ b/xen/common/grant_table.c
>>> @@ -2641,6 +2641,79 @@ do_grant_table_op(
>>>          }
>>>          break;
>>>      }
>>> +    case GNTTABOP_cache_flush:
>>> +    {
>>> +        struct gnttab_cache_flush cflush;
>>> +        struct domain *d, *owner;
>>> +        struct page_info *page;
>>> +        uint64_t mfn;
>>> +        void *v;
>>> +
>>> +        /* currently unimplemented */
>>> +        if ( count != 1 )
>>> +            return -ENOSYS;
>> ENOTSUPP (and elsewhere).
> ENOTSUPP doesn't seem to be defined in Xen. Should I take the
> opportunity to introduce it as 252?

Sorry. EOPNOTSUPP, 95.

~Andrew