[PATCH 2/18 V2]: PVH xen: add XENMEM_add_to_physmap_range

[Mukesh Rathor <mukesh.rathor@oracle.com>]

In this patch we add a new function xenmem_add_to_physmap_range(), and
change xenmem_add_to_physmap_once parameters so it can be called from
xenmem_add_to_physmap_range. There is no PVH specific change here.

Changes in V2:
   - Do not break parameter so xenmem_add_to_physmap_once() but pass in
     struct xen_add_to_physmap.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/mm.c |   82 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d00d9a2..6603752 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4268,7 +4268,8 @@ static int handle_iomem_range(unsigned long s, unsigned long e, void *p)
 
 static int xenmem_add_to_physmap_once(
     struct domain *d,
-    const struct xen_add_to_physmap *xatp)
+    const struct xen_add_to_physmap *xatp,
+    domid_t foreign_domid)
 {
     struct page_info *page = NULL;
     unsigned long gfn = 0; /* gcc ... */
@@ -4395,7 +4396,7 @@ static int xenmem_add_to_physmap(struct domain *d,
         start_xatp = *xatp;
         while ( xatp->size > 0 )
         {
-            rc = xenmem_add_to_physmap_once(d, xatp);
+            rc = xenmem_add_to_physmap_once(d, xatp, -1);
             if ( rc < 0 )
                 return rc;
 
@@ -4421,7 +4422,52 @@ static int xenmem_add_to_physmap(struct domain *d,
         return rc;
     }
 
-    return xenmem_add_to_physmap_once(d, xatp);
+    return xenmem_add_to_physmap_once(d, xatp, -1);
+}
+
+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 )
+            goto out;
+
+        rc = copy_from_guest_offset(&gpfn, xatpr->gpfns, xatpr->size-1, 1);
+        if ( rc < 0 )
+            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)
+            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)
@@ -4438,6 +4484,10 @@ long arch_memory_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg)
         if ( copy_from_guest(&xatp, arg, 1) )
             return -EFAULT;
 
+        /* This one is only supported for add_to_physmap_range */
+        if ( xatp.space == XENMAPSPACE_gmfn_foreign )
+            return -EINVAL;
+
         d = rcu_lock_domain_by_any_id(xatp.domid);
         if ( d == NULL )
             return -ESRCH;
@@ -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;
+
+        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