[PATCH v4 03/10] tools/libxl: add vmtrace_pt_size parameter

From: "Michał Leszczyński" <michal.leszczynski@cert.pl>
To: xen-devel@lists.xenproject.org
Cc: Julien Grall <julien@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	tamas.lengyel@intel.com, Wei Liu <wl@xen.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Michal Leszczynski <michal.leszczynski@cert.pl>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	George Dunlap <george.dunlap@citrix.com>,
	Jan Beulich <jbeulich@suse.com>,
	Anthony PERARD <anthony.perard@citrix.com>,
	luwei.kang@intel.com
Subject: [PATCH v4 03/10] tools/libxl: add vmtrace_pt_size parameter
Date: Tue, 30 Jun 2020 14:33:46 +0200	[thread overview]
Message-ID: <5f4f4b1afa432258daff43f2dc8119b6a441fff4.1593519420.git.michal.leszczynski@cert.pl> (raw)
In-Reply-To: <cover.1593519420.git.michal.leszczynski@cert.pl>
In-Reply-To: <cover.1593519420.git.michal.leszczynski@cert.pl>

From: Michal Leszczynski <michal.leszczynski@cert.pl>

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@cert.pl>
---
 docs/man/xl.cfg.5.pod.in             | 10 ++++++++++
 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                  | 20 ++++++++++++++++++++
 xen/common/domain.c                  | 12 ++++++++++++
 xen/include/public/domctl.h          |  1 +
 9 files changed, 57 insertions(+)

diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 0532739c1f..78f434b722 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -278,6 +278,16 @@ 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<vmtrace_pt_size=BYTES>
+
+Specifies the size of processor trace buffer that would be allocated
+for each vCPU belonging to this domain. Disabled (i.e. B<vmtrace_pt_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 935d3bc50a..ecace9634e 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 71709dc585..891e8e28d6 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 75862dc6ed..651d1f4c0f 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..4eba224590 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1861,6 +1861,26 @@ void parse_config_data(const char *config_source,
         }
     }
 
+    if (!xlu_cfg_get_long(config, "vmtrace_pt_size", &l, 1) && l) {
+        int32_t shift = 0;
+
+        if (l & (l - 1))
+        {
+            fprintf(stderr, "ERROR: pt buffer size must be a power of 2\n");
+            exit(1);
+        }
+
+        while (l >>= 1) ++shift;
+
+        if (shift <= XEN_PAGE_SHIFT)
+        {
+            fprintf(stderr, "ERROR: too small pt buffer\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));
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 0a33e0dfd6..27dcfbac8c 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -338,6 +338,12 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( config->vmtrace_pt_order && !vmtrace_supported )
+    {
+        dprintk(XENLOG_INFO, "Processor tracing is not supported\n");
+        return -EINVAL;
+    }
+
     return arch_sanitise_domain_config(config);
 }
 
@@ -443,6 +449,12 @@ struct domain *domain_create(domid_t domid,
         d->nr_pirqs = min(d->nr_pirqs, nr_irqs);
 
         radix_tree_init(&d->pirq_tree);
+
+        if ( config->vmtrace_pt_order )
+        {
+            uint32_t shift_val = config->vmtrace_pt_order + PAGE_SHIFT;
+            d->vmtrace_pt_size = (1ULL << shift_val);
+        }
     }
 
     if ( (err = arch_domain_create(d, config)) != 0 )
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 59bdc28c89..7b8289d436 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -92,6 +92,7 @@ struct xen_domctl_createdomain {
     uint32_t max_evtchn_port;
     int32_t max_grant_frames;
     int32_t max_maptrack_frames;
+    uint8_t vmtrace_pt_order;
 
     struct xen_arch_domainconfig arch;
 };
-- 
2.20.1


