xen: re-introduce support for grant v2 interface

[linux-2.6-block.git] / arch / x86 / xen / grant-table.c

diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
index 809b6c812654de4032bbe11efbf3e7e15b49b966..92ccc718152ddcebbd80c3127af6cbd4a6856c28 100644 (file)
--- a/arch/x86/xen/grant-table.c
+++ b/arch/x86/xen/grant-table.c
@@ -49,7 +49,7 @@
 static struct gnttab_vm_area {
        struct vm_struct *area;
        pte_t **ptes;
-} gnttab_shared_vm_area;
+} gnttab_shared_vm_area, gnttab_status_vm_area;
 
 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
                           unsigned long max_nr_gframes,
@@ -73,16 +73,43 @@ int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
        return 0;
 }
 
+int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
+                          unsigned long max_nr_gframes,
+                          grant_status_t **__shared)
+{
+       grant_status_t *shared = *__shared;
+       unsigned long addr;
+       unsigned long i;
+
+       if (shared == NULL)
+               *__shared = shared = gnttab_status_vm_area.area->addr;
+
+       addr = (unsigned long)shared;
+
+       for (i = 0; i < nr_gframes; i++) {
+               set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
+                          mfn_pte(frames[i], PAGE_KERNEL));
+               addr += PAGE_SIZE;
+       }
+
+       return 0;
+}
+
 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
 {
+       pte_t **ptes;
        unsigned long addr;
        unsigned long i;
 
+       if (shared == gnttab_status_vm_area.area->addr)
+               ptes = gnttab_status_vm_area.ptes;
+       else
+               ptes = gnttab_shared_vm_area.ptes;
+
        addr = (unsigned long)shared;
 
        for (i = 0; i < nr_gframes; i++) {
-               set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
-                          __pte(0));
+               set_pte_at(&init_mm, addr, ptes[i], __pte(0));
                addr += PAGE_SIZE;
        }
 }
@@ -102,12 +129,35 @@ static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
        return 0;
 }
 
-int arch_gnttab_init(unsigned long nr_shared)
+static void arch_gnttab_vfree(struct gnttab_vm_area *area)
 {
+       free_vm_area(area->area);
+       kfree(area->ptes);
+}
+
+int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
+{
+       int ret;
+
        if (!xen_pv_domain())
                return 0;
 
-       return arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
+       ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
+       if (ret < 0)
+               return ret;
+
+       /*
+        * Always allocate the space for the status frames in case
+        * we're migrated to a host with V2 support.
+        */
+       ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
+       if (ret < 0)
+               goto err;
+
+       return 0;
+err:
+       arch_gnttab_vfree(&gnttab_shared_vm_area);
+       return -ENOMEM;
 }
 
 #ifdef CONFIG_XEN_PVH