[PATCH V2 1/3] HACK: arm: initial XENMAPSPACE_gmfn_foreign

[Ian Campbell <ian.campbell@citrix.com>]

Should use same interface as hybrid x86.
---
 xen/arch/arm/mm.c             |   32 ++++++++++++++++++++++++++------
 xen/arch/x86/mm.c             |    2 ++
 xen/include/public/arch-arm.h |    1 +
 xen/include/public/memory.h   |   12 +++++++-----
 4 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 40ac176..d369ee3 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -470,12 +470,32 @@ static int xenmem_add_to_physmap_once(
 
     switch ( xatp->space )
     {
-        case XENMAPSPACE_shared_info:
-            if ( xatp->idx == 0 )
-                mfn = virt_to_mfn(d->shared_info);
-            break;
-        default:
-            return -ENOSYS;
+    case XENMAPSPACE_shared_info:
+        if ( xatp->idx == 0 )
+            mfn = virt_to_mfn(d->shared_info);
+        break;
+    case XENMAPSPACE_gmfn_foreign:
+    {
+        paddr_t maddr;
+        struct domain *od;
+
+        rc = rcu_lock_target_domain_by_id(xatp->foreign_domid, &od);
+        if ( rc < 0 )
+            return rc;
+        maddr = p2m_lookup(od, xatp->idx << PAGE_SHIFT);
+        if ( maddr == INVALID_PADDR )
+        {
+            printk("bad p2m lookup\n");
+            dump_p2m_lookup(od, xatp->idx << PAGE_SHIFT);
+            rcu_unlock_domain(od);
+            return -EINVAL;
+        }
+        mfn = maddr >> PAGE_SHIFT;
+        rcu_unlock_domain(od);
+        break;
+    }
+    default:
+        return -ENOSYS;
     }
 
     domain_lock(d);
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 9338575..9f63974 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4561,6 +4561,8 @@ static int xenmem_add_to_physmap_once(
             mfn = idx;
             page = mfn_to_page(mfn);
             break;
+        case XENMAPSPACE_gmfn_foreign:
+            return -ENOSYS;
         }
         default:
             break;
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index eb1add9..7ebe966 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -121,6 +121,7 @@ typedef uint64_t xen_pfn_t;
 #define XEN_LEGACY_MAX_VCPUS 1
 
 typedef uint32_t xen_ulong_t;
+#define PRI_xen_ulong PRIx32
 
 struct vcpu_guest_context {
     struct cpu_user_regs user_regs;         /* User-level CPU registers     */
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index 86d02c8..b2adfbe 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -212,11 +212,13 @@ struct xen_add_to_physmap {
     uint16_t    size;
 
     /* Source mapping space. */
-#define XENMAPSPACE_shared_info 0 /* shared info page */
-#define XENMAPSPACE_grant_table 1 /* grant table page */
-#define XENMAPSPACE_gmfn        2 /* GMFN */
-#define XENMAPSPACE_gmfn_range  3 /* GMFN range */
-    unsigned int space;
+#define XENMAPSPACE_shared_info  0 /* shared info page */
+#define XENMAPSPACE_grant_table  1 /* grant table page */
+#define XENMAPSPACE_gmfn         2 /* GMFN */
+#define XENMAPSPACE_gmfn_range   3 /* GMFN range */
+#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another guest */
+    uint16_t space;
+    domid_t foreign_domid; /* IFF gmfn_foreign */
 
 #define XENMAPIDX_grant_table_status 0x80000000
 
-- 
1.7.10.4