tools: introduce a new parameter to set a predefined rdm boundary

Previously we always fix that predefined boundary as 2G to handle
conflict between memory and rdm, but now this predefined boundar
can be changes with the parameter "rdm_mem_boundary" in .cfg file.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Checked-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index e6e0f70a81f98487e8facae6943ea962ebee5853..ce7ce85acdcf44697e1950981789aa66d173e1d5 100644 (file)
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -845,6 +845,28 @@ More information about Xen gfx_passthru feature is available
 on the XenVGAPassthrough L<http://wiki.xen.org/wiki/XenVGAPassthrough>
 wiki page.
 
+=item B<rdm_mem_boundary=MBYTES>
+
+Number of megabytes to set a boundary for checking rdm conflict.
+
+When RDM conflicts with RAM, RDM probably scatter the whole RAM space.
+Especially multiple RDM entries would worsen this to lead a complicated
+memory layout. So here we're trying to figure out a simple solution to
+avoid breaking existing layout. So when a conflict occurs,
+
+    #1. Above a predefined boundary
+        - move lowmem_end below reserved region to solve conflict;
+
+    #2. Below a predefined boundary
+        - Check strict/relaxed policy.
+        "strict" policy leads to fail libxl. Note when both policies
+        are specified on a given region, 'strict' is always preferred.
+        "relaxed" policy issue a warning message and also mask this
+        entry INVALID to indicate we shouldn't expose this entry to
+        hvmloader.
+
+Here the default is 2G.
+
 =item B<dtdev=[ "DTDEV_PATH", "DTDEV_PATH", ... ]>
 
 Specifies the host device tree nodes to passthrough to this guest. Each

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 5a7308d8420f85653341ebbbcb8fbcd6be4b604f..927b2d8c7365681e57200c7ba0e475e9b4842c07 100644 (file)
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -909,6 +909,12 @@ const char *libxl_defbool_to_string(libxl_defbool b);
 #define LIBXL_TIMER_MODE_DEFAULT -1
 #define LIBXL_MEMKB_DEFAULT ~0ULL
 
+/*
+ * We'd like to set a memory boundary to determine if we need to check
+ * any overlap with reserved device memory.
+ */
+#define LIBXL_RDM_MEM_BOUNDARY_MEMKB_DEFAULT (2048 * 1024)
+
 #define LIBXL_MS_VM_GENID_LEN 16
 typedef struct {
     uint8_t bytes[LIBXL_MS_VM_GENID_LEN];

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 5b5706203f314b88c1bb2780cfcab35126d4ec76..b27c53a627f70a8ab0f9b4ffb815d4b0c26d8680 100644 (file)
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -54,6 +54,10 @@ void libxl__rdm_setdefault(libxl__gc *gc, libxl_domain_build_info *b_info)
 {
     if (b_info->u.hvm.rdm.policy == LIBXL_RDM_RESERVE_POLICY_INVALID)
         b_info->u.hvm.rdm.policy = LIBXL_RDM_RESERVE_POLICY_RELAXED;
+
+    if (b_info->u.hvm.rdm_mem_boundary_memkb == LIBXL_MEMKB_DEFAULT)
+        b_info->u.hvm.rdm_mem_boundary_memkb =
+                            LIBXL_RDM_MEM_BOUNDARY_MEMKB_DEFAULT;
 }
 
 int libxl__domain_build_info_setdefault(libxl__gc *gc,

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 9af3b210dfcba57b4d55c204f208a9ad3b7bc645..0b7c39dbb2270eec329dc789e6130ce4011fd6c2 100644 (file)
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -930,12 +930,6 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
     int ret, rc = ERROR_FAIL;
     uint64_t mmio_start, lowmem_end, highmem_end;
     libxl_domain_build_info *const info = &d_config->b_info;
-    /*
-     * Currently we fix this as 2G to guarantee how to handle
-     * our rdm policy. But we'll provide a parameter to set
-     * this dynamically.
-     */
-    uint64_t rdm_mem_boundary = 0x80000000;
 
     memset(&args, 0, sizeof(struct xc_hvm_build_args));
     /* The params from the configuration file are in Mb, which are then
@@ -974,7 +968,7 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
     args.mmio_start = mmio_start;
 
     rc = libxl__domain_device_construct_rdm(gc, d_config,
-                                            rdm_mem_boundary,
+                                            info->u.hvm.rdm_mem_boundary_memkb*1024,
                                             &args);
     if (rc) {
         LOG(ERROR, "checking reserved device memory failed");

diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 157fa591ac9fccd580a65d0b51df62ed7e0b207a..9caaf442c9e12b24a340c2f6ab0ca64e3732698e 100644 (file)
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -503,6 +503,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
                                        ("ms_vm_genid",      libxl_ms_vm_genid),
                                        ("serial_list",      libxl_string_list),
                                        ("rdm", libxl_rdm_reserve),
+                                       ("rdm_mem_boundary_memkb", MemKB),
                                        ])),
                  ("pv", Struct(None, [("kernel", string),
                                       ("slack_memkb", MemKB),

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 1d45dd56a87bb880ec9edf6d5c517ee450c2fc94..c567a6a73aac9827176a890cc99bbfa604e3fe26 100644 (file)
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1583,6 +1583,9 @@ static void parse_config_data(const char *config_source,
                     exit(1);
             }
         }
+
+        if (!xlu_cfg_get_long (config, "rdm_mem_boundary", &l, 0))
+            b_info->u.hvm.rdm_mem_boundary_memkb = l * 1024;
         break;
     case LIBXL_DOMAIN_TYPE_PV:
     {