xen+tools: Introduce XEN_SYSCTL_PHYSCAP_vmtrace

We're about to introduce support for Intel Processor Trace, but similar
functionality exists in other platforms.

Aspects of vmtrace can reasonably can be common, so start with
XEN_SYSCTL_PHYSCAP_vmtrace and plumb the signal from Xen all the way down into
`xl info`.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/golang/xenlight/helpers.gen.go

@@ -3348,6 +3348,7 @@ x.CapHvmDirectio = bool(xc.cap_hvm_directio)
 x.CapHap = bool(xc.cap_hap)
 x.CapShadow = bool(xc.cap_shadow)
 x.CapIommuHapPtShare = bool(xc.cap_iommu_hap_pt_share)
+x.CapVmtrace = bool(xc.cap_vmtrace)
 
  return nil}
 
@@ -3378,6 +3379,7 @@ xc.cap_hvm_directio = C.bool(x.CapHvmDirectio)
 xc.cap_hap = C.bool(x.CapHap)
 xc.cap_shadow = C.bool(x.CapShadow)
 xc.cap_iommu_hap_pt_share = C.bool(x.CapIommuHapPtShare)
+xc.cap_vmtrace = C.bool(x.CapVmtrace)
 
  return nil
  }

tools/golang/xenlight/types.gen.go

@@ -1000,6 +1000,7 @@ CapHvmDirectio bool
 CapHap bool
 CapShadow bool
 CapIommuHapPtShare bool
+CapVmtrace bool
 }
 
 type Connectorinfo struct {

tools/include/libxl.h

@@ -481,6 +481,13 @@
  */
 #define LIBXL_HAVE_DEVICE_PCI_NAME 1
 
+/*
+ * LIBXL_HAVE_PHYSINFO_CAP_VMTRACE indicates that libxl_physinfo has a
+ * cap_vmtrace field, which indicates the availability of platform tracing
+ * functionality.
+ */
+#define LIBXL_HAVE_PHYSINFO_CAP_VMTRACE 1
+
 /*
  * libxl ABI compatibility
  *

tools/libs/light/libxl.c

@@ -402,6 +402,8 @@ int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
         !!(xcphysinfo.capabilities & XEN_SYSCTL_PHYSCAP_shadow);
     physinfo->cap_iommu_hap_pt_share =
         !!(xcphysinfo.capabilities & XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share);
+    physinfo->cap_vmtrace =
+        !!(xcphysinfo.capabilities & XEN_SYSCTL_PHYSCAP_vmtrace);
 
     GC_FREE;
     return 0;

tools/libs/light/libxl_types.idl

@@ -1053,6 +1053,7 @@ libxl_physinfo = Struct("physinfo", [
     ("cap_hap", bool),
     ("cap_shadow", bool),
     ("cap_iommu_hap_pt_share", bool),
+    ("cap_vmtrace", bool),
     ], dir=DIR_OUT)
 
 libxl_connectorinfo = Struct("connectorinfo", [

tools/ocaml/libs/xc/xenctrl.ml

@@ -116,6 +116,7 @@ type physinfo_cap_flag =
 	| CAP_HAP
 	| CAP_Shadow
 	| CAP_IOMMU_HAP_PT_SHARE
+	| CAP_Vmtrace
 
 type physinfo =
 {

tools/ocaml/libs/xc/xenctrl.mli

@@ -101,6 +101,7 @@ type physinfo_cap_flag =
   | CAP_HAP
   | CAP_Shadow
   | CAP_IOMMU_HAP_PT_SHARE
+  | CAP_Vmtrace
 
 type physinfo = {
   threads_per_core : int;

tools/xl/xl_info.c

@@ -210,14 +210,15 @@ static void output_physinfo(void)
          info.hw_cap[4], info.hw_cap[5], info.hw_cap[6], info.hw_cap[7]
         );
 
-    maybe_printf("virt_caps              :%s%s%s%s%s%s%s\n",
+    maybe_printf("virt_caps              :%s%s%s%s%s%s%s%s\n",
          info.cap_pv ? " pv" : "",
          info.cap_hvm ? " hvm" : "",
          info.cap_hvm && info.cap_hvm_directio ? " hvm_directio" : "",
          info.cap_pv && info.cap_hvm_directio ? " pv_directio" : "",
          info.cap_hap ? " hap" : "",
          info.cap_shadow ? " shadow" : "",
-         info.cap_iommu_hap_pt_share ? " iommu_hap_pt_share" : ""
+         info.cap_iommu_hap_pt_share ? " iommu_hap_pt_share" : "",
+         info.cap_vmtrace ? " vmtrace" : ""
         );
 
     vinfo = libxl_get_version_info(ctx);

xen/common/domain.c

@@ -82,6 +82,8 @@ struct vcpu *idle_vcpu[NR_CPUS] __read_mostly;
 
 vcpu_info_t dummy_vcpu_info;
 
+bool __read_mostly vmtrace_available;
+
 static void __domain_finalise_shutdown(struct domain *d)
 {
     struct vcpu *v;

xen/common/sysctl.c

@@ -277,6 +277,8 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
             if ( iommu_hap_pt_share )
                 pi->capabilities |= XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share;
         }
+        if ( vmtrace_available )
+            pi->capabilities |= XEN_SYSCTL_PHYSCAP_vmtrace;
 
         if ( copy_to_guest(u_sysctl, op, 1) )
             ret = -EFAULT;

xen/include/public/sysctl.h

@@ -100,9 +100,10 @@ struct xen_sysctl_tbuf_op {
 #define _XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share 5
 #define XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share  \
     (1u << _XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share)
+#define XEN_SYSCTL_PHYSCAP_vmtrace       (1 << 6)
 
 /* Max XEN_SYSCTL_PHYSCAP_* constant.  Used for ABI checking. */
-#define XEN_SYSCTL_PHYSCAP_MAX XEN_SYSCTL_PHYSCAP_iommu_hap_pt_share
+#define XEN_SYSCTL_PHYSCAP_MAX XEN_SYSCTL_PHYSCAP_vmtrace
 
 struct xen_sysctl_physinfo {
     uint32_t threads_per_core;

xen/include/xen/domain.h

@@ -131,4 +131,6 @@ void vnuma_destroy(struct vnuma_info *vnuma);
 static inline void vnuma_destroy(struct vnuma_info *vnuma) { ASSERT(!vnuma); }
 #endif
 
+extern bool vmtrace_available;
+
 #endif /* __XEN_DOMAIN_H__ */