[PATCH 3/3] x86/sysctl: Retrofit XEN_SYSCTL_cpu_featureset_{pv,hvm}_max

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Featuresets are supposed to be disappearing when the CPU policy infrastructure
is complete, but that has taken longer than expected, and isn't going to be
complete imminently either.

In the meantime, Xen does have proper default/max featuresets, and xen-cpuid
can even get them via the XEN_SYSCTL_cpu_policy_* interface, but only knows
now to render them nicely via the featureset interface.

Differences between default and max are a frequent source of errors,
frequently too in secret leading up to an embargo, so extend the featureset
sysctl to allow xen-cpuid to render them all nicely.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Christian Lindig <christian.lindig@xxxxxxxxxx>
CC: David Scott <dave@xxxxxxxxxx>
CC: Edwin Török <edwin.torok@xxxxxxxxx>
CC: Rob Hoes <Rob.Hoes@xxxxxxxxxx>

I actually this SYSCTL extention in the XenServer patchqueue for reasons that
started with the TSX fiasco; I have no idea why its taken until now to think
it would be a good idea to wire into xen-cpuid too...
---
 tools/misc/xen-cpuid.c          | 10 ++++++----
 tools/ocaml/libs/xc/xenctrl.ml  |  8 +++++++-
 tools/ocaml/libs/xc/xenctrl.mli |  8 +++++++-
 xen/arch/x86/sysctl.c           |  4 +++-
 xen/include/public/sysctl.h     |  2 ++
 5 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c
index 227df7352e2b..37a7eaa8edfc 100644
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -247,10 +247,12 @@ static const struct {
 #define COL_ALIGN "18"
 
 static const char *const fs_names[] = {
-    [XEN_SYSCTL_cpu_featureset_host] = "Host",
-    [XEN_SYSCTL_cpu_featureset_raw]  = "Raw",
-    [XEN_SYSCTL_cpu_featureset_pv]   = "PV",
-    [XEN_SYSCTL_cpu_featureset_hvm]  = "HVM",
+    [XEN_SYSCTL_cpu_featureset_raw]     = "Raw",
+    [XEN_SYSCTL_cpu_featureset_host]    = "Host",
+    [XEN_SYSCTL_cpu_featureset_pv]      = "PV Default",
+    [XEN_SYSCTL_cpu_featureset_hvm]     = "HVM Default",
+    [XEN_SYSCTL_cpu_featureset_pv_max]  = "PV Max",
+    [XEN_SYSCTL_cpu_featureset_hvm_max] = "HVM Max",
 };
 
 static void dump_leaf(uint32_t leaf, const char *const *strs)
diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml
index a59dee093897..e4096bf92c1d 100644
--- a/tools/ocaml/libs/xc/xenctrl.ml
+++ b/tools/ocaml/libs/xc/xenctrl.ml
@@ -370,7 +370,13 @@ external version_changeset: handle -> string = 
"stub_xc_version_changeset"
 external version_capabilities: handle -> string =
   "stub_xc_version_capabilities"
 
-type featureset_index = Featureset_raw | Featureset_host | Featureset_pv | 
Featureset_hvm
+type featureset_index =
+  | Featureset_raw
+  | Featureset_host
+  | Featureset_pv
+  | Featureset_hvm
+  | Featureset_pv_max
+  | Featureset_hvm_max
 external get_cpu_featureset : handle -> featureset_index -> int64 array = 
"stub_xc_get_cpu_featureset"
 
 external watchdog : handle -> int -> int32 -> int
diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli
index 3154e90f4f98..ef2254537430 100644
--- a/tools/ocaml/libs/xc/xenctrl.mli
+++ b/tools/ocaml/libs/xc/xenctrl.mli
@@ -297,7 +297,13 @@ external version_changeset : handle -> string = 
"stub_xc_version_changeset"
 external version_capabilities : handle -> string
   = "stub_xc_version_capabilities"
 
-type featureset_index = Featureset_raw | Featureset_host | Featureset_pv | 
Featureset_hvm
+type featureset_index =
+  | Featureset_raw
+  | Featureset_host
+  | Featureset_pv
+  | Featureset_hvm
+  | Featureset_pv_max
+  | Featureset_hvm_max
 external get_cpu_featureset : handle -> featureset_index -> int64 array = 
"stub_xc_get_cpu_featureset"
 
 external pages_to_kib : int64 -> int64 = "stub_pages_to_kib"
diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
index f42a3b843ba7..6600eb43471b 100644
--- a/xen/arch/x86/sysctl.c
+++ b/xen/arch/x86/sysctl.c
@@ -323,14 +323,16 @@ long arch_do_sysctl(
 
     case XEN_SYSCTL_get_cpu_featureset:
     {
-        static const struct cpuid_policy *const policy_table[4] = {
+        static const struct cpuid_policy *const policy_table[6] = {
             [XEN_SYSCTL_cpu_featureset_raw]  = &raw_cpuid_policy,
             [XEN_SYSCTL_cpu_featureset_host] = &host_cpuid_policy,
 #ifdef CONFIG_PV
             [XEN_SYSCTL_cpu_featureset_pv]   = &pv_def_cpuid_policy,
+            [XEN_SYSCTL_cpu_featureset_pv_max] = &pv_max_cpuid_policy,
 #endif
 #ifdef CONFIG_HVM
             [XEN_SYSCTL_cpu_featureset_hvm]  = &hvm_def_cpuid_policy,
+            [XEN_SYSCTL_cpu_featureset_hvm_max] = &hvm_max_cpuid_policy,
 #endif
         };
         const struct cpuid_policy *p = NULL;
diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 001a4de27375..e8dded9fb94a 100644
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -796,6 +796,8 @@ struct xen_sysctl_cpu_featureset {
 #define XEN_SYSCTL_cpu_featureset_host     1
 #define XEN_SYSCTL_cpu_featureset_pv       2
 #define XEN_SYSCTL_cpu_featureset_hvm      3
+#define XEN_SYSCTL_cpu_featureset_pv_max   4
+#define XEN_SYSCTL_cpu_featureset_hvm_max  5
     uint32_t index;       /* IN: Which featureset to query? */
     uint32_t nr_features; /* IN/OUT: Number of entries in/written to
                            * 'features', or the maximum number of features if
-- 
2.30.2