Re: [Xen-devel] [PATCH 2/18 V2]: PVH xen: add XENMEM_add_to_physmap_range

[Tim Deegan <tim@xxxxxxx>]

At 17:20 -0700 on 15 Mar (1363368018), Mukesh Rathor wrote:
> +static noinline int xenmem_add_to_physmap_range(struct domain *d,
> +                                       struct xen_add_to_physmap_range 
> *xatpr)
> +{
> +    int rc;
> +
> +    /* Process entries in reverse order to allow continuations */
> +    while ( xatpr->size > 0 )
> +    {
> +        xen_ulong_t idx;
> +        xen_pfn_t gpfn;
> +        struct xen_add_to_physmap xatp;
> +
> +        rc = copy_from_guest_offset(&idx, xatpr->idxs, xatpr->size-1, 1);
> +        if ( rc < 0 )

copy_from_guest_offset() returns the number of bytes that could not be
copied, which would never be < 0.

> +            goto out;
> +
> +        rc = copy_from_guest_offset(&gpfn, xatpr->gpfns, xatpr->size-1, 1);
> +        if ( rc < 0 )

Ditto.

> +            goto out;
> +
> +        xatp.space = xatpr->space;
> +        xatp.idx = idx;
> +        xatp.gpfn = gpfn;
> +        rc = xenmem_add_to_physmap_once(d, &xatp, xatpr->foreign_domid);
> +
> +        if (rc)

Whitespace missing.

> +            goto out;
> +
> +        xatpr->size--;
> +
> +        /* Check for continuation if it's not the last interation */
> +        if ( xatpr->size > 0 && hypercall_preempt_check() )
> +        {
> +            rc = -EAGAIN;
> +            goto out;
> +        }
> +    }
> +
> +    rc = 0;
> +
> +out:
> +    return rc;
> +
>  }
>  
>  long arch_memory_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg)
> @@ -4465,6 +4515,32 @@ long arch_memory_op(int op, 
> XEN_GUEST_HANDLE_PARAM(void) arg)
>          return rc;
>      }
>  
> +    case XENMEM_add_to_physmap_range:
> +    {
> +        struct xen_add_to_physmap_range xatpr;
> +        struct domain *d;
> +
> +        if ( copy_from_guest(&xatpr, arg, 1) )
> +            return -EFAULT;
> +
> +        rc = rcu_lock_target_domain_by_id(xatpr.domid, &d);
> +        if ( rc != 0 )
> +            return rc;

There should be an XSM hook here somewhere.

> +        rc = xenmem_add_to_physmap_range(d, &xatpr);
> +
> +        rcu_unlock_domain(d);
> +
> +        if ( rc && copy_to_guest(arg, &xatpr, 1) )
> +            rc = -EFAULT;
> +
> +        if ( rc == -EAGAIN )
> +            rc = hypercall_create_continuation(
> +                __HYPERVISOR_memory_op, "ih", op, arg);
> +
> +        return rc;
> +    }
> +
>      case XENMEM_set_memory_map:
>      {
>          struct xen_foreign_memory_map fmap;
> -- 
> 1.7.2.3
> 
> 
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