[PATCH 03/18] PVH xen: create domctl_memory_mapping() function

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

In this patch, XEN_DOMCTL_memory_mapping code is put into a function so
it can be shared later for PVH. There is no change in it's
functionality.

Changes in V2:
  - Remove PHYSDEVOP_map_iomem sub hypercall, and the code supporting it
           as the IO region is mapped transparently now.

Changes in V3:
  - change loop control variable to ulong from int.
  - move priv checks to the function.

Changes in V5:
  - Move iomem_access_permitted check to case statment from the function
    as current doesn't point to dom0 during construct_dom0.

Changes in V6:
  - Move iomem_access_permitted back to domctl_memory_mapping() as it should
    be after the sanity and wrap checks of mfns/gfns.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/domctl.c    |  130 +++++++++++++++++++++++++---------------------
 xen/include/xen/domain.h |    2 +
 2 files changed, 72 insertions(+), 60 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index f87d6ab..ce32245 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -46,6 +46,75 @@ static int gdbsx_guest_mem_io(
     return (iop->remain ? -EFAULT : 0);
 }
 
+long domctl_memory_mapping(struct domain *d, unsigned long gfn,
+                           unsigned long mfn, unsigned long nr_mfns,
+                           bool_t add_map)
+{
+    unsigned long i;
+    long ret;
+
+    if ( (mfn + nr_mfns - 1) < mfn || /* wrap? */
+         ((mfn | (mfn + nr_mfns - 1)) >> (paddr_bits - PAGE_SHIFT)) ||
+         (gfn + nr_mfns - 1) < gfn ) /* wrap? */
+        return -EINVAL;
+
+    /* caller construct_dom0() runs on idle vcpu */
+    if ( !is_idle_vcpu(current) &&
+         !iomem_access_permitted(current->domain, mfn, mfn + nr_mfns - 1) )
+        return -EPERM;
+
+    ret = xsm_iomem_permission(XSM_HOOK, d, mfn, mfn + nr_mfns - 1, add_map);
+    if ( ret )
+        return ret;
+
+    if ( add_map )
+    {
+        printk(XENLOG_G_INFO
+               "memory_map:add: dom%d gfn=%lx mfn=%lx nr=%lx\n",
+               d->domain_id, gfn, mfn, nr_mfns);
+
+        ret = iomem_permit_access(d, mfn, mfn + nr_mfns - 1);
+        if ( !ret && paging_mode_translate(d) )
+        {
+            for ( i = 0; !ret && i < nr_mfns; i++ )
+                if ( !set_mmio_p2m_entry(d, gfn + i, _mfn(mfn + i)) )
+                    ret = -EIO;
+            if ( ret )
+            {
+                printk(XENLOG_G_WARNING
+                       "memory_map:fail: dom%d gfn=%lx mfn=%lx\n",
+                       d->domain_id, gfn + i, mfn + i);
+                while ( i-- )
+                    clear_mmio_p2m_entry(d, gfn + i);
+                if ( iomem_deny_access(d, mfn, mfn + nr_mfns - 1) &&
+                     is_hardware_domain(current->domain) )
+                    printk(XENLOG_ERR
+                           "memory_map: failed to deny dom%d access to [%lx,%lx]\n",
+                           d->domain_id, mfn, mfn + nr_mfns - 1);
+            }
+        }
+    }
+    else
+    {
+        printk(XENLOG_G_INFO
+               "memory_map:remove: dom%d gfn=%lx mfn=%lx nr=%lx\n",
+               d->domain_id, gfn, mfn, nr_mfns);
+
+        if ( paging_mode_translate(d) )
+            for ( i = 0; i < nr_mfns; i++ )
+                add_map |= !clear_mmio_p2m_entry(d, gfn + i);
+        ret = iomem_deny_access(d, mfn, mfn + nr_mfns - 1);
+        if ( !ret && add_map )
+            ret = -EIO;
+        if ( ret && is_hardware_domain(current->domain) )
+            printk(XENLOG_ERR
+                   "memory_map: error %ld %s dom%d access to [%lx,%lx]\n",
+                   ret, add_map ? "removing" : "denying", d->domain_id,
+                   mfn, mfn + nr_mfns - 1);
+    }
+    return ret;
+}
+
 long arch_do_domctl(
     struct xen_domctl *domctl, struct domain *d,
     XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
@@ -625,67 +694,8 @@ long arch_do_domctl(
         unsigned long mfn = domctl->u.memory_mapping.first_mfn;
         unsigned long nr_mfns = domctl->u.memory_mapping.nr_mfns;
         int add = domctl->u.memory_mapping.add_mapping;
-        unsigned long i;
-
-        ret = -EINVAL;
-        if ( (mfn + nr_mfns - 1) < mfn || /* wrap? */
-             ((mfn | (mfn + nr_mfns - 1)) >> (paddr_bits - PAGE_SHIFT)) ||
-             (gfn + nr_mfns - 1) < gfn ) /* wrap? */
-            break;
 
-        ret = -EPERM;
-        if ( !iomem_access_permitted(current->domain, mfn, mfn + nr_mfns - 1) )
-            break;
-
-        ret = xsm_iomem_mapping(XSM_HOOK, d, mfn, mfn + nr_mfns - 1, add);
-        if ( ret )
-            break;
-
-        if ( add )
-        {
-            printk(XENLOG_G_INFO
-                   "memory_map:add: dom%d gfn=%lx mfn=%lx nr=%lx\n",
-                   d->domain_id, gfn, mfn, nr_mfns);
-
-            ret = iomem_permit_access(d, mfn, mfn + nr_mfns - 1);
-            if ( !ret && paging_mode_translate(d) )
-            {
-                for ( i = 0; !ret && i < nr_mfns; i++ )
-                    if ( !set_mmio_p2m_entry(d, gfn + i, _mfn(mfn + i)) )
-                        ret = -EIO;
-                if ( ret )
-                {
-                    printk(XENLOG_G_WARNING
-                           "memory_map:fail: dom%d gfn=%lx mfn=%lx\n",
-                           d->domain_id, gfn + i, mfn + i);
-                    while ( i-- )
-                        clear_mmio_p2m_entry(d, gfn + i);
-                    if ( iomem_deny_access(d, mfn, mfn + nr_mfns - 1) &&
-                         is_hardware_domain(current->domain) )
-                        printk(XENLOG_ERR
-                               "memory_map: failed to deny dom%d access to [%lx,%lx]\n",
-                               d->domain_id, mfn, mfn + nr_mfns - 1);
-                }
-            }
-        }
-        else
-        {
-            printk(XENLOG_G_INFO
-                   "memory_map:remove: dom%d gfn=%lx mfn=%lx nr=%lx\n",
-                   d->domain_id, gfn, mfn, nr_mfns);
-
-            if ( paging_mode_translate(d) )
-                for ( i = 0; i < nr_mfns; i++ )
-                    add |= !clear_mmio_p2m_entry(d, gfn + i);
-            ret = iomem_deny_access(d, mfn, mfn + nr_mfns - 1);
-            if ( !ret && add )
-                ret = -EIO;
-            if ( ret && is_hardware_domain(current->domain) )
-                printk(XENLOG_ERR
-                       "memory_map: error %ld %s dom%d access to [%lx,%lx]\n",
-                       ret, add ? "removing" : "denying", d->domain_id,
-                       mfn, mfn + nr_mfns - 1);
-        }
+        ret = domctl_memory_mapping(d, gfn, mfn, nr_mfns, add);
     }
     break;
 
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index a057069..9d6287c 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -89,4 +89,6 @@ extern unsigned int xen_processor_pmbits;
 
 extern bool_t opt_dom0_vcpus_pin;
 
+extern long domctl_memory_mapping(struct domain *d, unsigned long gfn,
+                    unsigned long mfn, unsigned long nr_mfns, bool_t add_map);
 #endif /* __XEN_DOMAIN_H__ */
-- 
1.7.2.3