[PATCH v2 11/12] libxl: add API wrapper for libxl_set_memory_target

[Olaf Hering <olaf@xxxxxxxxx>]

Upcoming changes will use different LIBXL_API_VERSION variants.

Prepare libxl_set_memory_target, which changed the storage size of
parameter "target_memkb" in Xen 4.8.

No functional change intended.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
---
 src/libxl/libxl_api_wrapper.h | 27 +++++++++++++++++++++++++++
 src/libxl/libxl_domain.c      |  6 +++---
 src/libxl/libxl_driver.c      |  4 ++--
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/src/libxl/libxl_api_wrapper.h b/src/libxl/libxl_api_wrapper.h
index 26c2215cb7..a9627f7983 100644
--- a/src/libxl/libxl_api_wrapper.h
+++ b/src/libxl/libxl_api_wrapper.h
@@ -20,6 +20,7 @@
 
 #pragma once
 
+#include <limits.h>
 #include <libxl.h>
 
 static inline int
@@ -188,3 +189,29 @@ libxlSendTriggerWrapper(libxl_ctx *ctx,
 
     return ret;
 }
+
+static inline int
+libxlSetMemoryTargetWrapper(libxl_ctx *ctx,
+                        uint32_t domid,
+                        uint64_t target_memkb,
+                        int relative,
+                        int enforce)
+{
+    int ret = -1;
+
+    /* Technically this guard could be LIBXL_HAVE_MEMKB_64BITS */
+#if LIBXL_API_VERSION < 0x040800
+    if (target_memkb < UINT_MAX) {
+        uint32_t val32 = target_memkb;
+
+        ret = libxl_set_memory_target(ctx, domid, val32, relative, enforce);
+    }
+#else
+    if (target_memkb < LLONG_MAX) {
+        int64_t val64 = target_memkb;
+        ret = libxl_set_memory_target(ctx, domid, val64, relative, enforce);
+    }
+#endif
+
+    return ret;
+}
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index ac613b96b9..7ffafb9023 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -1010,7 +1010,7 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl_domain_config *d_config)
 {
     uint64_t needed_mem;
     uint64_t free_mem;
-    int32_t target_mem;
+    uint64_t target_mem;
     int tries = 3;
     int wait_secs = 10;
 
@@ -1025,8 +1025,8 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl_domain_config *d_config)
             return 0;
 
         target_mem = free_mem - needed_mem;
-        if (libxl_set_memory_target(ctx, 0, target_mem,
-                                    /* relative */ 1, 0) < 0)
+        if (libxlSetMemoryTargetWrapper(ctx, 0, target_mem,
+                                        /* relative */ 1, 0) < 0)
             goto error;
 
         if (libxl_wait_for_memory_target(ctx, 0, wait_secs) < 0)
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 18098734fc..f130790484 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -1695,8 +1695,8 @@ libxlDomainSetMemoryFlags(virDomainPtr dom, unsigned long newmem,
 
             /* Unlock virDomainObj while ballooning memory */
             virObjectUnlock(vm);
-            res = libxl_set_memory_target(cfg->ctx, vm->def->id, newmem, 0,
-                                          /* force */ 1);
+            res = libxlSetMemoryTargetWrapper(cfg->ctx, vm->def->id, newmem, 0,
+                                              /* force */ 1);
             virObjectLock(vm);
             if (res < 0) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,