[Xen-API] [PATCH] CA-38844: Add support for Intel FlexMigration on Nehalem/Westmere

[Rob Hoes <rob.hoes@xxxxxxxxxx>]

# HG changeset patch
# User Rob Hoes <rob.hoes@xxxxxxxxxx>
CA-38844: Add support for Intel FlexMigration on Nehalem/Westmere

Note: this patch should go in together with the flex-maskability patch in 
xen-api.hg.

Signed-off-by: Rob Hoes <rob.hoes@xxxxxxxxxx>

diff -r b4c441b39984 cpuid/cpuid.ml
--- a/cpuid/cpuid.ml    Wed Apr 07 11:57:42 2010 +0100
+++ b/cpuid/cpuid.ml    Thu Apr 08 13:37:38 2010 +0100
@@ -23,6 +23,7 @@
 (* === Types and conversion === *)
 
 type manufacturer = AMD | Intel | Unknown
+and maskability = No | Base | Full
 and features =
        {
                base_ecx: int32;
@@ -38,7 +39,7 @@
                stepping: int32;
                features: features;
                physical_features: features;
-               maskable: bool;
+               maskable: maskability;
        }
 
 let features_to_string f =
@@ -109,23 +110,31 @@
 (* Does this Intel CPU support "FlexMigration"? 
  * It's not sensibly documented, so check by model *)
 let has_flexmigration family model stepping = 
-       family > 0x6l || (model > 0x17l || (model = 0x17l && stepping >= 4l))
+       if family <> 0x6l then
+               No
+       else if model = 0x1dl || (model = 0x17l && stepping >= 4l) then
+               Base
+       else if (model = 0x1al && stepping > 2l) ||
+               model = 0x1el || model = 0x25l || model = 0x2cl ||
+               model = 0x2el || model = 0x2fl then
+               Full
+       else
+               No
 
 (* Does this AMD CPU have Extended Migration Technology? 
  * Known good on Barcelona and better; did exist on some older CPUs 
  * but not really documented which ones *)
 let has_emt family = 
-       family >= 0x10l
+       if family >= 0x10l then
+               Full
+       else
+               No
        
 let is_maskable manufacturer family model stepping =
        match manufacturer with 
-       | Unknown -> false
-       | Intel ->
-               if has_flexmigration family model stepping then true
-               else false
-       | AMD ->
-               if has_emt family then true
-               else false
+       | Unknown -> No
+       | Intel -> has_flexmigration family model stepping
+       | AMD -> has_emt family
 
 let get_features_from_xen () =
        let features = 
@@ -193,29 +202,25 @@
        (* Manufacturers need to be the same *)
        if manufacturer != cpu.manufacturer then 
                raise ManufacturersDiffer;
-       (* Check whether masking is supported on the CPU *)
-       if not cpu.maskable then 
+       (* Check whether the features can be obtained by masking the physical 
features *)
+       let base = (logand cpu.physical_features.base_ecx features.base_ecx) = 
features.base_ecx 
+               && (logand cpu.physical_features.base_edx features.base_edx) = 
features.base_edx in
+       match cpu.maskable with
+       | No ->
                begin match cpu.manufacturer with 
                | Unknown -> raise (MaskingNotSupported "Unknown CPU 
manufacturer")
                | Intel -> raise (MaskingNotSupported "CPU does not have 
FlexMigration")
                | AMD -> raise (MaskingNotSupported "CPU does not have Extended 
Migration Technology")
-               end;
-       (* Check whether the features can be obtained by masking the physical 
features *)
-       let possible = (logand cpu.physical_features.base_ecx 
features.base_ecx) = features.base_ecx 
-               && (logand cpu.physical_features.base_edx features.base_edx) = 
features.base_edx
-               && begin match manufacturer with 
-               | Intel ->
-                       (* Intel can't mask extented features but doesn't (yet) 
need to *)
-                       cpu.physical_features.ext_ecx = features.ext_ecx
-                               && cpu.physical_features.ext_edx = 
features.ext_edx
-               | AMD ->
-                       (logand cpu.physical_features.ext_ecx features.ext_ecx) 
= features.ext_ecx 
-                               && (logand cpu.physical_features.ext_edx 
features.ext_edx) = features.ext_edx
-               | _ -> false
                end
-       in
-       if not possible then
-               raise (InvalidFeatureString "CPU features cannot be masked to 
obtain given features")
+       | Base ->
+               if not (base && cpu.physical_features.ext_ecx = features.ext_ecx
+                       && cpu.physical_features.ext_edx = features.ext_edx) 
then
+                       raise (InvalidFeatureString "CPU features cannot be 
masked to obtain \
+                               given features (only base features can be 
masked)")
+       | Full ->
+               if not (base && (logand cpu.physical_features.ext_ecx 
features.ext_ecx) = features.ext_ecx 
+                       && (logand cpu.physical_features.ext_edx 
features.ext_edx) = features.ext_edx) then
+                       raise (InvalidFeatureString "CPU features cannot be 
masked to obtain given features")
 
 let xen_masking_string cpu features = 
        let rec stringify reglist = 
diff -r b4c441b39984 cpuid/cpuid.mli
--- a/cpuid/cpuid.mli   Wed Apr 07 11:57:42 2010 +0100
+++ b/cpuid/cpuid.mli   Thu Apr 08 13:37:38 2010 +0100
@@ -21,6 +21,12 @@
 | Intel                (** Intel *)
 | Unknown      (** Other manufacturer *)
 
+(** Indicates whether CPUID features can be masked. *)
+and maskability =
+| No           (** No masking possible *)
+| Base         (** Only base features can be masked *)
+| Full         (** Both base and extended features can be masked *)
+
 (** CPU feature bit vector. *)
 and features
 
@@ -33,7 +39,7 @@
                stepping: int32;                                (** Stepping 
number of the CPU *)
                features: features;                             (** Feature bit 
vector of the CPU *)
                physical_features: features;    (** Physical Feature bit vector 
of the CPU *)
-               maskable: bool;                                 (** Boolean 
indicating whether the CPU supports
+               maskable: maskability;                  (** Indicates whether 
the CPU supports
                                                                                
Intel FlexMigration or AMD Extended Migration,
                                                                                
or cannot be masked *)
        }

Attachment: flexmigration
Description: Text document

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