xen: implement the privcmd user-space device

This device is only attached to priviledged domains, and allows the
toolstack to interact with Xen. The two functions of the privcmd
interface is to allow the execution of hypercalls from user-space, and
the mapping of foreign domain memory.

Sponsored by: Citrix Systems R&D

i386/include/xen/hypercall.h:
amd64/include/xen/hypercall.h:
 - Introduce a function to make generic hypercalls into Xen.

xen/interface/xen.h:
xen/interface/memory.h:
 - Import the new hypercall XENMEM_add_to_physmap_range used by
   auto-translated guests to map memory from foreign domains.

dev/xen/privcmd/privcmd.c:
 - This device has the following functions:
   - Allow user-space applications to make hypercalls into Xen.
   - Allow user-space applications to map memory from foreign domains,
     this is accomplished using the newly introduced hypercall
     (XENMEM_add_to_physmap_range).

xen/privcmd.h:
 - Public ioctl interface for the privcmd device.

x86/xen/hvm.c:
 - Remove declaration of hypercall_page, now it's declared in
   hypercall.h.

conf/files:
 - Add the privcmd device to the build process.

2 files changed, 34 insertions, 0 deletions

diff --git a/sys/xen/interface/memory.h b/sys/xen/interface/memory.h
index 86d02c8..cdb7a58 100644
--- a/sys/xen/interface/memory.h
+++ b/sys/xen/interface/memory.h
@@ -198,6 +198,14 @@ struct xen_machphys_mapping {
 typedef struct xen_machphys_mapping xen_machphys_mapping_t;
 DEFINE_XEN_GUEST_HANDLE(xen_machphys_mapping_t);
 
+#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, XENMEM_add_to_physmap only. */
+#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another dom,
+                                    * XENMEM_add_to_physmap_range only.
+                                    */
+
 /*
  * Sets the GPFN at which a particular page appears in the specified guest's
  * pseudophysical address space.
@@ -248,6 +256,31 @@ DEFINE_XEN_GUEST_HANDLE(xen_remove_from_physmap_t);
 /*** REMOVED ***/
 /*#define XENMEM_translate_gpfn_list  8*/
 
+#define XENMEM_add_to_physmap_range 23
+struct xen_add_to_physmap_range {
+    /* IN */
+    /* Which domain to change the mapping for. */
+    domid_t domid;
+    uint16_t space; /* => enum phys_map_space */
+
+    /* Number of pages to go through */
+    uint16_t size;
+    domid_t foreign_domid; /* IFF gmfn_foreign */
+
+    /* Indexes into space being mapped. */
+    XEN_GUEST_HANDLE(xen_ulong_t) idxs;
+
+    /* GPFN in domid where the source mapping page should appear. */
+    XEN_GUEST_HANDLE(xen_pfn_t) gpfns;
+
+    /* OUT */
+
+    /* Per index error code. */
+    XEN_GUEST_HANDLE(int) errs;
+};
+typedef struct xen_add_to_physmap_range xen_add_to_physmap_range_t;
+DEFINE_XEN_GUEST_HANDLE(xen_add_to_physmap_range_t);
+
 /*
  * Returns the pseudo-physical memory map as it was when the domain
  * was started (specified by XENMEM_set_memory_map).
diff --git a/sys/xen/interface/xen.h b/sys/xen/interface/xen.h
index b2f6c50..9425520 100644
--- a/sys/xen/interface/xen.h
+++ b/sys/xen/interface/xen.h
@@ -51,6 +51,7 @@ DEFINE_XEN_GUEST_HANDLE(void);
 
 DEFINE_XEN_GUEST_HANDLE(uint64_t);
 DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
+DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
 #endif
 
 /*