Such helper allow converting a cpu policy into an array of
xen_cpuid_leaf_t and xen_msr_entry_t elements, which matches the
current interface of the CPUID/MSR functions. This is required in
order for the user to be able to parse the CPUID/MSR data.

No user of the interface introduced in this patch.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 tools/include/xenctrl.h         |  5 +++++
 tools/libs/guest/xg_cpuid_x86.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 34d979d11da..a4827b1ae6a 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -2602,6 +2602,11 @@ int xc_cpu_policy_get_system(xc_interface *xch, unsigned int policy_idx,
 int xc_cpu_policy_get_domain(xc_interface *xch, uint32_t domid,
                              xc_cpu_policy_t policy);
 
+/* Manipulate a policy via architectural representations. */
+int xc_cpu_policy_serialise(xc_interface *xch, const xc_cpu_policy_t policy,
+                            xen_cpuid_leaf_t *leaves, uint32_t *nr_leaves,
+                            xen_msr_entry_t *msrs, uint32_t *nr_msrs);
+
 int xc_get_cpu_levelling_caps(xc_interface *xch, uint32_t *caps);
 int xc_get_cpu_featureset(xc_interface *xch, uint32_t index,
                           uint32_t *nr_features, uint32_t *featureset);
diff --git a/tools/libs/guest/xg_cpuid_x86.c b/tools/libs/guest/xg_cpuid_x86.c
index 1394e503f3d..918591a128c 100644
--- a/tools/libs/guest/xg_cpuid_x86.c
+++ b/tools/libs/guest/xg_cpuid_x86.c
@@ -757,3 +757,35 @@ int xc_cpu_policy_get_domain(xc_interface *xch, uint32_t domid,
 
     return rc;
 }
+
+int xc_cpu_policy_serialise(xc_interface *xch, const xc_cpu_policy_t p,
+                            xen_cpuid_leaf_t *leaves, uint32_t *nr_leaves,
+                            xen_msr_entry_t *msrs, uint32_t *nr_msrs)
+{
+    int rc;
+
+    if ( leaves )
+    {
+        rc = x86_cpuid_copy_to_buffer(&p->cpuid, leaves, nr_leaves);
+        if ( rc )
+        {
+            ERROR("Failed to serialize CPUID policy");
+            errno = -rc;
+            return -1;
+        }
+    }
+
+    if ( msrs )
+    {
+        rc = x86_msr_copy_to_buffer(&p->msr, msrs, nr_msrs);
+        if ( rc )
+        {
+            ERROR("Failed to serialize MSR policy");
+            errno = -rc;
+            return -1;
+        }
+    }
+
+    errno = 0;
+    return 0;
+}
-- 
2.30.1