[PATCH v5 05/11] tools/libxl: add vmtrace_pt_size parameter

[Michał Leszczyński <michal.leszczynski@xxxxxxx>]

From: Michal Leszczynski <michal.leszczynski@xxxxxxx>

Allow to specify the size of per-vCPU trace buffer upon
domain creation. This is zero by default (meaning: not enabled).

Signed-off-by: Michal Leszczynski <michal.leszczynski@xxxxxxx>
---
 docs/man/xl.cfg.5.pod.in             | 11 +++++++++++
 tools/golang/xenlight/helpers.gen.go |  2 ++
 tools/golang/xenlight/types.gen.go   |  1 +
 tools/libxl/libxl.h                  |  8 ++++++++
 tools/libxl/libxl_create.c           |  1 +
 tools/libxl/libxl_types.idl          |  2 ++
 tools/xl/xl_parse.c                  | 22 ++++++++++++++++++++++
 7 files changed, 47 insertions(+)

diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 0532739c1f..670759f6bd 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -278,6 +278,17 @@ memory=8096 will report significantly less memory 
available for use
 than a system with maxmem=8096 memory=8096 due to the memory overhead
 of having to track the unused pages.
 
+=item B<processor_trace_buffer_size=BYTES>
+
+Specifies the size of processor trace buffer that would be allocated
+for each vCPU belonging to this domain. Disabled (i.e.
+B<processor_trace_buffer_size=0> by default. This must be set to
+non-zero value in order to be able to use processor tracing features
+with this domain.
+
+B<NOTE>: The size value must be between 4 kB and 4 GB and it must
+be also a power of 2.
+
 =back
 
 =head3 Guest Virtual NUMA Configuration
diff --git a/tools/golang/xenlight/helpers.gen.go 
b/tools/golang/xenlight/helpers.gen.go
index 152c7e8e6b..bfc37b69c8 100644
--- a/tools/golang/xenlight/helpers.gen.go
+++ b/tools/golang/xenlight/helpers.gen.go
@@ -1117,6 +1117,7 @@ return fmt.Errorf("invalid union key '%v'", x.Type)}
 x.ArchArm.GicVersion = GicVersion(xc.arch_arm.gic_version)
 x.ArchArm.Vuart = VuartType(xc.arch_arm.vuart)
 x.Altp2M = Altp2MMode(xc.altp2m)
+x.VmtracePtOrder = int(xc.vmtrace_pt_order)
 
  return nil}
 
@@ -1592,6 +1593,7 @@ return fmt.Errorf("invalid union key '%v'", x.Type)}
 xc.arch_arm.gic_version = C.libxl_gic_version(x.ArchArm.GicVersion)
 xc.arch_arm.vuart = C.libxl_vuart_type(x.ArchArm.Vuart)
 xc.altp2m = C.libxl_altp2m_mode(x.Altp2M)
+xc.vmtrace_pt_order = C.int(x.VmtracePtOrder)
 
  return nil
  }
diff --git a/tools/golang/xenlight/types.gen.go 
b/tools/golang/xenlight/types.gen.go
index 663c1e86b4..f9b07ac862 100644
--- a/tools/golang/xenlight/types.gen.go
+++ b/tools/golang/xenlight/types.gen.go
@@ -516,6 +516,7 @@ GicVersion GicVersion
 Vuart VuartType
 }
 Altp2M Altp2MMode
+VmtracePtOrder int
 }
 
 type domainBuildInfoTypeUnion interface {
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 1cd6c38e83..4abb521756 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -438,6 +438,14 @@
  */
 #define LIBXL_HAVE_CREATEINFO_PASSTHROUGH 1
 
+/*
+ * LIBXL_HAVE_VMTRACE_PT_ORDER indicates that
+ * libxl_domain_create_info has a vmtrace_pt_order parameter, which
+ * allows to enable pre-allocation of processor tracing buffers
+ * with the given order of size.
+ */
+#define LIBXL_HAVE_VMTRACE_PT_ORDER 1
+
 /*
  * libxl ABI compatibility
  *
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 2814818e34..82b595161a 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -608,6 +608,7 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config 
*d_config,
             .max_evtchn_port = b_info->event_channels,
             .max_grant_frames = b_info->max_grant_frames,
             .max_maptrack_frames = b_info->max_maptrack_frames,
+            .vmtrace_pt_order = b_info->vmtrace_pt_order,
         };
 
         if (info->type != LIBXL_DOMAIN_TYPE_PV) {
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 9d3f05f399..1c5dd43e4d 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -645,6 +645,8 @@ libxl_domain_build_info = Struct("domain_build_info",[
     # supported by x86 HVM and ARM support is planned.
     ("altp2m", libxl_altp2m_mode),
 
+    ("vmtrace_pt_order", integer),
+
     ], dir=DIR_IN,
        copy_deprecated_fn="libxl__domain_build_info_copy_deprecated",
 )
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index 61b4ef7b7e..279f7c14d3 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1861,6 +1861,28 @@ void parse_config_data(const char *config_source,
         }
     }
 
+    if (!xlu_cfg_get_long(config, "processor_trace_buffer_size", &l, 1) && l) {
+        int32_t shift = 0;
+
+        if (l & (l - 1))
+        {
+            fprintf(stderr, "ERROR: processor_trace_buffer_size "
+                           "- must be a power of 2\n");
+            exit(1);
+        }
+
+        while (l >>= 1) ++shift;
+
+        if (shift <= XEN_PAGE_SHIFT)
+        {
+            fprintf(stderr, "ERROR: processor_trace_buffer_size "
+                           "- value is too small\n");
+            exit(1);
+        }
+
+        b_info->vmtrace_pt_order = shift - XEN_PAGE_SHIFT;
+    }
+
     if (!xlu_cfg_get_list(config, "ioports", &ioports, &num_ioports, 0)) {
         b_info->num_ioports = num_ioports;
         b_info->ioports = calloc(num_ioports, sizeof(*b_info->ioports));
-- 
2.17.1