xen: Introduce xen_modified_memory.

This function is to be used during live migration. Every write access to the
guest memory should call this funcion so the Xen tools knows which pages are
dirty.

Backport of 910b38e4dc4c37683c8b821e75a7f4cf095e4b21

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alex Bligh <alex@alex.org.uk>

diff --git a/hw/xen.h b/hw/xen.h
index 21621115e48624ef8a0c0f351cbdb7e9e8c9aafa..359a275e7e3f4cfc8f008270f125c721a0ebea6c 100644 (file)
--- a/hw/xen.h
+++ b/hw/xen.h
@@ -45,6 +45,7 @@ void xenstore_store_pv_console_info(int i, struct CharDriverState *chr);
 
 #if defined(NEED_CPU_H) && !defined(CONFIG_USER_ONLY)
 void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size);
+void xen_modified_memory(ram_addr_t start, ram_addr_t length);
 #endif
 
 #if defined(CONFIG_XEN) && CONFIG_XEN_CTRL_INTERFACE_VERSION < 400

diff --git a/xen-all.c b/xen-all.c
index 6b4e511822f7174d4449a2200ab97c70278c4d30..121289da7d7f6d491653b88237d9648b5dc5ac2e 100644 (file)
--- a/xen-all.c
+++ b/xen-all.c
@@ -1135,3 +1135,24 @@ void destroy_hvm_domain(bool reboot)
         xc_interface_close(xc_handle);
     }
 }
+
+void xen_modified_memory(ram_addr_t start, ram_addr_t length)
+{
+    if (unlikely(cpu_physical_memory_get_dirty_tracking())) {
+        int rc;
+        ram_addr_t start_pfn, nb_pages;
+
+        if (length == 0) {
+            length = TARGET_PAGE_SIZE;
+        }
+        start_pfn = start >> TARGET_PAGE_BITS;
+        nb_pages = ((start + length + TARGET_PAGE_SIZE - 1) >> TARGET_PAGE_BITS)
+            - start_pfn;
+        rc = xc_hvm_modified_memory(xen_xc, xen_domid, start_pfn, nb_pages);
+        if (rc) {
+            fprintf(stderr,
+                    "%s failed for "RAM_ADDR_FMT" ("RAM_ADDR_FMT"): %i, %s\n",
+                    __func__, start, nb_pages, rc, strerror(-rc));
+        }
+    }
+}

diff --git a/xen-stub.c b/xen-stub.c
index 25317ec2ffb38948cb027e483832b6ad78a75de9..7b5447764f097f0a52ad0105160b970240269a14 100644 (file)
--- a/xen-stub.c
+++ b/xen-stub.c
@@ -48,3 +48,7 @@ int xen_init(void)
 void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
 {
 }
+
+void xen_modified_memory(ram_addr_t start, ram_addr_t length)
+{
+}