xen: Use newly added dmops for mapping VGA memory

Xen unstable (to be in 4.11) has two new dmops, relocate_memory and
pin_memory_cacheattr. Use these to set up the VGA memory, replacing the
previous calls to libxc. This allows the VGA console to work properly
when QEMU is running restricted (-xen-domid-restrict).

Wrapper functions are provided to allow QEMU to work with older versions
of Xen.

Tweak the error handling while making this change:
* Report pin_memory_cacheattr errors.
* Report errors even when DEBUG_HVM is not set. This is useful for
trying to understand why VGA is not working, since otherwise it just
fails silently.
* Fix the return values when an error occurs. The functions now
consistently return -1 and set errno.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 4bd30a3..2eed6fc 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -89,6 +89,38 @@ typedef xc_interface xendevicemodel_handle;
 
 #endif
 
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41100
+
+static inline int xendevicemodel_relocate_memory(
+    xendevicemodel_handle *dmod, domid_t domid, uint32_t size, uint64_t src_gfn,
+    uint64_t dst_gfn)
+{
+    uint32_t i;
+    int rc;
+
+    for (i = 0; i < size; i++) {
+        unsigned long idx = src_gfn + i;
+        xen_pfn_t gpfn = dst_gfn + i;
+
+        rc = xc_domain_add_to_physmap(xen_xc, domid, XENMAPSPACE_gmfn, idx,
+                                      gpfn);
+        if (rc) {
+            return rc;
+        }
+    }
+
+    return 0;
+}
+
+static inline int xendevicemodel_pin_memory_cacheattr(
+    xendevicemodel_handle *dmod, domid_t domid, uint64_t start, uint64_t end,
+    uint32_t type)
+{
+    return xc_domain_pin_memory_cacheattr(xen_xc, domid, start, end, type);
+}
+
+#endif /* CONFIG_XEN_CTRL_INTERFACE_VERSION < 41100 */
+
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41000
 
 #define XEN_COMPAT_PHYSMAP