[PATCH v6 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             | 13 +++++++++++++
 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          |  4 ++++
 tools/xl/xl_parse.c                  | 22 ++++++++++++++++++++++
 7 files changed, 51 insertions(+)

diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 0532739c1f..ddef9b6014 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -683,6 +683,19 @@ If this option is not specified then it will default to 
B<false>.
 
 =back
 
+=item B<processor_trace_buf_kb=KBYTES>
+
+Specifies the size of processor trace buffer that would be allocated
+for each vCPU belonging to this domain. Disabled (i.e.
+B<processor_trace_buf_kb=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>: In order to use Intel Processor Trace feature, this value
+must be between 8 kB and 4 GB and it must be a power of 2.
+
+=back
+
 =head2 Devices
 
 The following options define the paravirtual, emulated and physical
diff --git a/tools/golang/xenlight/helpers.gen.go 
b/tools/golang/xenlight/helpers.gen.go
index 152c7e8e6b..3ce6f2374b 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.ProcessorTraceBufKb = int(xc.processor_trace_buf_kb)
 
  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.processor_trace_buf_kb = C.int(x.ProcessorTraceBufKb)
 
  return nil
  }
diff --git a/tools/golang/xenlight/types.gen.go 
b/tools/golang/xenlight/types.gen.go
index 663c1e86b4..f4bc16c0fd 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
+ProcessorTraceBufKb int
 }
 
 type domainBuildInfoTypeUnion interface {
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 1cd6c38e83..fbf222967a 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -438,6 +438,14 @@
  */
 #define LIBXL_HAVE_CREATEINFO_PASSTHROUGH 1
 
+/*
+ * LIBXL_HAVE_PROCESSOR_TRACE_BUF_KB indicates that
+ * libxl_domain_create_info has a processor_trace_buf_kb parameter, which
+ * allows to enable pre-allocation of processor tracing buffers of given
+ * size.
+ */
+#define LIBXL_HAVE_PROCESSOR_TRACE_BUF_KB 1
+
 /*
  * libxl ABI compatibility
  *
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 2814818e34..4d6318124a 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,
+            .processor_trace_buf_kb = b_info->processor_trace_buf_kb,
         };
 
         if (info->type != LIBXL_DOMAIN_TYPE_PV) {
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 9d3f05f399..748fde65ab 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -645,6 +645,10 @@ libxl_domain_build_info = Struct("domain_build_info",[
     # supported by x86 HVM and ARM support is planned.
     ("altp2m", libxl_altp2m_mode),
 
+    # Size of preallocated processor trace buffers (in KBYTES).
+    # Use zero value to disable this feature.
+    ("processor_trace_buf_kb", 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..87e373b413 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_buf_kb", &l, 1) && l) {
+        if (l & (l - 1)) {
+            fprintf(stderr, "ERROR: processor_trace_buf_kb"
+                            " - must be a power of 2\n");
+            exit(1);
+        }
+
+        if (l < 8) {
+            fprintf(stderr, "ERROR: processor_trace_buf_kb"
+                            " - value is too small\n");
+            exit(1);
+        }
+
+        if (l > 1024*1024*4) {
+            fprintf(stderr, "ERROR: processor_trace_buf_kb"
+                            " - value is too large\n");
+            exit(1);
+        }
+
+        b_info->processor_trace_buf_kb = l;
+    }
+
     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