[PATCH 17/18] PVH xen: Introduce p2m_map_foreign

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

In this patch, a new type p2m_map_foreign for pages that a dom0 maps from
foreign domains its creating is introduced.

Changes in V2:
   - Make guest_physmap_add_entry() same for PVH in terms of overwriting old
     entry.
   - In set_foreign_p2m_entry() do locked get_gfn and not unlocked.
   - Replace ASSERT with return -EINVAL in do_physdev_op.
   - Remove unnecessary check for PVH in do_physdev_op().

Changes in V3:
   - remove changes unrelated to this patch.

Changes in V5:
   - remove mmio check for highest gfn tracking.
   - set_foreign_p2m_entry looks same as set_mmio_p2m_entry, so make a common
     function for both.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/mm/p2m-ept.c |    1 +
 xen/arch/x86/mm/p2m-pt.c  |    1 +
 xen/arch/x86/mm/p2m.c     |   29 +++++++++++++++++++++--------
 xen/include/asm-x86/p2m.h |    4 ++++
 4 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 595c6e7..67c200c 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -75,6 +75,7 @@ static void ept_p2m_type_to_flags(ept_entry_t *entry, p2m_type_t type, p2m_acces
             entry->w = 0;
             break;
         case p2m_grant_map_rw:
+        case p2m_map_foreign:
             entry->r = entry->w = 1;
             entry->x = 0;
             break;
diff --git a/xen/arch/x86/mm/p2m-pt.c b/xen/arch/x86/mm/p2m-pt.c
index 302b621..021a6af 100644
--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -89,6 +89,7 @@ static unsigned long p2m_type_to_flags(p2m_type_t t, mfn_t mfn)
     case p2m_ram_rw:
         return flags | P2M_BASE_FLAGS | _PAGE_RW;
     case p2m_grant_map_rw:
+    case p2m_map_foreign:
         return flags | P2M_BASE_FLAGS | _PAGE_RW | _PAGE_NX_BIT;
     case p2m_mmio_direct:
         if ( !rangeset_contains_singleton(mmio_ro_ranges, mfn_x(mfn)) )
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index f5ddd20..1646fac 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -523,7 +523,7 @@ p2m_remove_page(struct p2m_domain *p2m, unsigned long gfn, unsigned long mfn,
         for ( i = 0; i < (1UL << page_order); i++ )
         {
             mfn_return = p2m->get_entry(p2m, gfn + i, &t, &a, 0, NULL);
-            if ( !p2m_is_grant(t) && !p2m_is_shared(t) )
+            if ( !p2m_is_grant(t) && !p2m_is_shared(t) && !p2m_is_foreign(t) )
                 set_gpfn_from_mfn(mfn+i, INVALID_M2P_ENTRY);
             ASSERT( !p2m_is_valid(t) || mfn + i == mfn_x(mfn_return) );
         }
@@ -754,10 +754,9 @@ void p2m_change_type_range(struct domain *d,
     p2m_unlock(p2m);
 }
 
-
-
-int
-set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
+static int
+set_typed_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
+                    p2m_type_t gfn_p2mt)
 {
     int rc = 0;
     p2m_access_t a;
@@ -782,16 +781,30 @@ set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
         set_gpfn_from_mfn(mfn_x(omfn), INVALID_M2P_ENTRY);
     }
 
-    P2M_DEBUG("set mmio %lx %lx\n", gfn, mfn_x(mfn));
-    rc = set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2m_mmio_direct, p2m->default_access);
+    P2M_DEBUG("set %d %lx %lx\n", gfn_p2mt, gfn, mfn_x(mfn));
+    rc = set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, gfn_p2mt,
+                       p2m->default_access);
     gfn_unlock(p2m, gfn, 0);
     if ( 0 == rc )
         gdprintk(XENLOG_ERR,
-            "set_mmio_p2m_entry: set_p2m_entry failed! mfn=%08lx\n",
+            "%s: set_p2m_entry failed! mfn=%08lx\n", __func__,
             mfn_x(get_gfn_query_unlocked(p2m->domain, gfn, &ot)));
     return rc;
 }
 
+/* Returns: True for success. 0 for failure. */
+int 
+set_foreign_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
+{
+    return set_typed_p2m_entry(d, gfn, mfn, p2m_map_foreign);
+}
+
+int
+set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
+{
+    return set_typed_p2m_entry(d, gfn, mfn, p2m_mmio_direct);
+}
+
 int
 clear_mmio_p2m_entry(struct domain *d, unsigned long gfn)
 {
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 43583b2..6fc71a1 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -70,6 +70,7 @@ typedef enum {
     p2m_ram_paging_in = 11,       /* Memory that is being paged in */
     p2m_ram_shared = 12,          /* Shared or sharable memory */
     p2m_ram_broken = 13,          /* Broken page, access cause domain crash */
+    p2m_map_foreign  = 14,        /* ram pages from foreign domain */
 } p2m_type_t;
 
 /*
@@ -180,6 +181,7 @@ typedef unsigned int p2m_query_t;
 #define p2m_is_sharable(_t) (p2m_to_mask(_t) & P2M_SHARABLE_TYPES)
 #define p2m_is_shared(_t)   (p2m_to_mask(_t) & P2M_SHARED_TYPES)
 #define p2m_is_broken(_t)   (p2m_to_mask(_t) & P2M_BROKEN_TYPES)
+#define p2m_is_foreign(_t)  (p2m_to_mask(_t) & p2m_to_mask(p2m_map_foreign))
 
 /* Per-p2m-table state */
 struct p2m_domain {
@@ -510,6 +512,8 @@ p2m_type_t p2m_change_type(struct domain *d, unsigned long gfn,
 int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
 int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn);
 
+/* Set foreign mfn in the current guest's p2m table. */
+int set_foreign_p2m_entry(struct domain *domp, unsigned long gfn, mfn_t mfn);
 
 /* 
  * Populate-on-demand
-- 
1.7.2.3