(* === Types and conversion === *)
type manufacturer = AMD | Intel | Unknown
-and maskability = No | Base | Full
and features =
{
base_ecx: int32;
stepping: int32;
features: features;
physical_features: features;
- maskable: maskability;
+ maskable: bool;
}
let features_to_string f =
(* Does this Intel CPU support "FlexMigration"?
* It's not sensibly documented, so check by model *)
let has_flexmigration family model stepping =
- 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
+ family > 0x6l || (model > 0x17l || (model = 0x17l && stepping >= 4l))
(* 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 =
- if family >= 0x10l then
- Full
- else
- No
+ family >= 0x10l
let is_maskable manufacturer family model stepping =
match manufacturer with
- | Unknown -> No
- | Intel -> has_flexmigration family model stepping
- | AMD -> has_emt family
-
-let get_features_from_xen () =
- let features =
- try Xc.with_intf (fun xc -> Xc.get_boot_cpufeatures xc)
- with _ -> 0l, 0l, 0l, 0l, 0l, 0l, 0l, 0l
- in
- match features with
- | base_ecx, base_edx, ext_ecx, ext_edx,
- masked_base_ecx, masked_base_edx, masked_ext_ecx, masked_ext_edx ->
- {
- base_ecx = masked_base_ecx;
- base_edx = masked_base_edx;
- ext_ecx = masked_ext_ecx;
- ext_edx = masked_ext_edx
- },
- {
- base_ecx = base_ecx;
- base_edx = base_edx;
- ext_ecx = ext_ecx;
- ext_edx = ext_edx
- }
-
-let get_current_mask () =
- let masks = Xen_cmdline.list_cpuid_masks () in
- let get_mask m =
- if List.mem_assoc m masks = false then
- 0xffffffffl
- else
- Int32.of_string (List.assoc m masks)
- in
- {
- base_ecx = get_mask "cpuid_mask_ecx";
- base_edx = get_mask "cpuid_mask_edx";
- ext_ecx = get_mask "cpuid_mask_ext_ecx";
- ext_edx = get_mask "cpuid_mask_ext_edx"
- }
-
+ | Unknown -> false
+ | Intel ->
+ if has_flexmigration family model stepping then true
+ else false
+ | AMD ->
+ if has_emt family then true
+ else false
+
+let get_physical_features features =
+ let features_file = "/var/xapi/features" in
+ try
+ let data = Unixext.read_whole_file_to_string features_file in
+ string_to_features data
+ with _ ->
+ let data = features_to_string features in
+ Unixext.write_string_to_file features_file data;
+ features
+
let read_cpu_info () =
let manufacturer = read_manufacturer () in
let family = read_family () in
let model = read_model () in
- let features, phy_features = get_features_from_xen () in
+ let features = read_features () in
let stepping = read_stepping () in
{
manufacturer = manufacturer;
model = model;
stepping = stepping;
features = features;
- physical_features = phy_features;
+ physical_features = get_physical_features features;
maskable = is_maskable manufacturer family model stepping;
}
(* === Masking checks === *)
-let mask_features features mask =
- {
- base_ecx = logand features.base_ecx mask.base_ecx;
- base_edx = logand features.base_edx mask.base_edx;
- ext_ecx = logand features.ext_ecx mask.ext_ecx;
- ext_edx = logand features.ext_edx mask.ext_edx;
- }
-
let assert_maskability cpu manufacturer features =
(* Manufacturers need to be the same *)
if manufacturer != cpu.manufacturer then
raise ManufacturersDiffer;
- (* 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 ->
+ (* Check whether masking is supported on the CPU *)
+ if not cpu.maskable then
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
- | 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")
+ in
+ if not possible then
+ raise (InvalidFeatureString "CPU features cannot be masked to obtain given features")
let xen_masking_string cpu features =
let rec stringify reglist =
| 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
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: maskability; (** Indicates whether the CPU supports
+ maskable: bool; (** Boolean indicating whether the CPU supports
Intel FlexMigration or AMD Extended Migration,
or cannot be masked *)
}
(** {2 Masking Checks} *)
-(** Apply a mask to given features. *)
-val mask_features : features -> features -> features
-
-(** Check that this CPU can be masked to fit the pool. Raises exception
- * indicating the reason if this is not possible. *)
+(** Check that this CPU can be masked to fit the pool. Raises {!CannotMaskCpu}
+ * including a reason string if this is not possible. *)
val assert_maskability : cpu_info -> manufacturer -> features -> unit
(** Return the CPU masking string to add to the Xen command-line,
projects / xcp / xen-api-libs.git / commitdiff