>>> On 22.03.18 at 12:55, <paul.durr...@citrix.com> wrote:
> --- a/xen/common/memory.c
> +++ b/xen/common/memory.c
> @@ -967,6 +967,94 @@ static long xatp_permission_check(struct domain *d,
> unsigned int space)
> return xsm_add_to_physmap(XSM_TARGET, current->domain, d);
> }
>
> +static int acquire_resource(
> + XEN_GUEST_HANDLE_PARAM(xen_mem_acquire_resource_t) arg)
> +{
> + struct domain *d, *currd = current->domain;
> + xen_mem_acquire_resource_t xmar;
> + /*
> + * The mfn_list and gfn_list (below) arrays are ok on stack for the
> + * moment since they are small, but if they need to grow in future
> + * use-cases then per-CPU arrays or heap allocations may be required.
> + */
> + xen_pfn_t mfn_list[2];
> + int rc;
> +
> + if ( copy_from_guest(&xmar, arg, 1) )
> + return -EFAULT;
> +
> + if ( xmar.flags != 0 )
> + return -EINVAL;
> +
> + if ( guest_handle_is_null(xmar.frame_list) )
> + {
> + if ( xmar.nr_frames )
> + return -EINVAL;
> +
> + xmar.nr_frames = ARRAY_SIZE(mfn_list);
> +
> + if ( __copy_field_to_guest(arg, &xmar, nr_frames) )
> + return -EFAULT;
> +
> + return 0;
> + }
> +
> + if ( xmar.nr_frames > ARRAY_SIZE(mfn_list) )
> + return -E2BIG;
> +
> + rc = rcu_lock_remote_domain_by_id(xmar.domid, &d);
> + if ( rc )
> + return rc;
> +
> + rc = xsm_domain_resource_map(XSM_DM_PRIV, d);
> + if ( rc )
> + goto out;
> +
> + switch ( xmar.type )
> + {
> + default:
> + rc = -EOPNOTSUPP;
> + break;
> + }
> +
> + if ( rc )
> + goto out;
> +
> + if ( !paging_mode_translate(currd) )
> + {
> + if ( copy_to_guest(xmar.frame_list, mfn_list, xmar.nr_frames) )
> + rc = -EFAULT;
> + }
> + else
> + {
> + xen_pfn_t gfn_list[ARRAY_SIZE(mfn_list)];
> + unsigned int i;
> +
> + if ( copy_from_guest(gfn_list, xmar.frame_list, xmar.nr_frames) )
> + rc = -EFAULT;
> +
> + for ( i = 0; !rc && i < xmar.nr_frames; i++ )
> + {
> + rc = set_foreign_p2m_entry(currd, gfn_list[i],
> + _mfn(mfn_list[i]));
> + if ( rc )
> + /*
> + * Make sure rc is -EIO for any iteration other than
> + * the first.
> + */
> + rc = i ? -EIO : rc;
Perhaps easier as
/*
* Make sure rc is -EIO for any iteration other than
* the first.
*/
if ( rc && i )
rc = -EIO;
? Looks like the comment could then also be a single line one.
> + }
> + }
> +
> + if ( xmar.flags != 0 &&
> + __copy_field_to_guest(arg, &xmar, flags) )
> + rc = -EFAULT;
> +
> + out:
> + rcu_unlock_domain(d);
> + return rc;
> +}
Blank line please ahead of main "return".
> --- a/xen/include/public/memory.h
> +++ b/xen/include/public/memory.h
> @@ -599,6 +599,59 @@ struct xen_reserved_device_memory_map {
> typedef struct xen_reserved_device_memory_map
> xen_reserved_device_memory_map_t;
> DEFINE_XEN_GUEST_HANDLE(xen_reserved_device_memory_map_t);
>
> +/*
> + * Get the pages for a particular guest resource, so that they can be
> + * mapped directly by a tools domain.
> + */
> +#define XENMEM_acquire_resource 28
> +struct xen_mem_acquire_resource {
> + /* IN - The domain whose resource is to be mapped */
> + domid_t domid;
> + /* IN - the type of resource */
> + uint16_t type;
> + /*
> + * IN - a type-specific resource identifier, which must be zero
> + * unless stated otherwise.
> + */
> + uint32_t id;
> + /*
> + * IN/OUT - As an IN parameter number of frames of the resource
> + * to be mapped. However, if the specified value is 0 and
> + * frame_list is NULL then this field will be set to the
> + * maximum value supported by the implementation on return.
> + */
> + uint32_t nr_frames;
> + /*
> + * OUT - Must be zero on entry. On return this may contain a bitwise
> + * OR of the following values.
> + */
> + uint32_t flags;
> +
> + /* The resource pages have been assigned to the tools domain */
> +#define _XENMEM_resource_flag_tools_owned 0
> +#define XENMEM_resource_flag_tools_owned (1u <<
> _XENMEM_resource_flag_tools_owned)
Is "tools" really an appropriate (and "flag" a necessary) name
component here? How about e.g. XENMEM_res_acq_caller_owned?
> --- a/xen/include/xlat.lst
> +++ b/xen/include/xlat.lst
> @@ -86,6 +86,7 @@
> ! memory_map memory.h
> ! memory_reservation memory.h
> ! mem_access_op memory.h
> +! mem_acquire_resource memory.h
Why ! ? The layout doesn't appear to differ between native and
compat. Or wait, the handle does, but why is that not
XEN_GUEST_HANDLE_64()? (I've skipped the compat layer code
in this round of review for that reason.)
Jan
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