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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86/cpuid: Introduce named feature bitfields
commit 8c6510fb66847ab7c0141078b335f1acb07d1341
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Jan 11 11:59:02 2017 +0000
Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Jan 11 11:59:02 2017 +0000
x86/cpuid: Introduce named feature bitfields
It greatly aids the readibility of code to express feature checks with their
direct name (e.g. p->basic.mtrr or p->extd.lm), rarther that by a field and
a
bitmask. gen-cpuid.py is augmented to calculate a suitable declaration to
live in a union with the underlying feature word.
gen-cpuid.py doesn't know Xen's choice of naming for the feature word
indicies
(and arguably shouldn't care), so provides the declarations in terms of
their
numeric feature word index. The DECL_BITFIELD() macro (local to
cpuid_policy)
takes a feature word index name and chooses the right declaration, to aid
clarity.
All X86_FEATURE_*'s are included in the naming, other than the features
fast-forwarded from other state (APIC, OSXSAVE, OSPKE), whose value cannot
be
read out of the feature word.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
xen/include/asm-x86/cpuid.h | 61 ++++++++++++++++++++++++++++++++++++++++-----
xen/tools/gen-cpuid.py | 32 ++++++++++++++++++++++++
2 files changed, 87 insertions(+), 6 deletions(-)
diff --git a/xen/include/asm-x86/cpuid.h b/xen/include/asm-x86/cpuid.h
index 0592b38..c4ca06a 100644
--- a/xen/include/asm-x86/cpuid.h
+++ b/xen/include/asm-x86/cpuid.h
@@ -92,6 +92,10 @@ struct cpuid_policy
* Everything else should be considered inaccurate, and not necesserily 0.
*/
+#define DECL_BITFIELD(word) _DECL_BITFIELD(FEATURESET_ ## word)
+#define _DECL_BITFIELD(x) __DECL_BITFIELD(x)
+#define __DECL_BITFIELD(x) CPUID_BITFIELD_ ## x
+
/* Basic leaves: 0x000000xx */
union {
struct cpuid_leaf raw[CPUID_GUEST_NR_BASIC];
@@ -100,7 +104,15 @@ struct cpuid_policy
uint32_t max_leaf, /* b */:32, /* c */:32, /* d */:32;
/* Leaf 0x1 - Family/model/stepping and features. */
- uint32_t /* a */:32, /* b */:32, _1c, _1d;
+ uint32_t /* a */:32, /* b */:32;
+ union {
+ uint32_t _1c;
+ struct { DECL_BITFIELD(1c); };
+ };
+ union {
+ uint32_t _1d;
+ struct { DECL_BITFIELD(1d); };
+ };
};
} basic;
@@ -109,7 +121,19 @@ struct cpuid_policy
struct cpuid_leaf raw[CPUID_GUEST_NR_FEAT];
struct {
/* Subleaf 0. */
- uint32_t max_subleaf, _7b0, _7c0, _7d0;
+ uint32_t max_subleaf;
+ union {
+ uint32_t _7b0;
+ struct { DECL_BITFIELD(7b0); };
+ };
+ union {
+ uint32_t _7c0;
+ struct { DECL_BITFIELD(7c0); };
+ };
+ union {
+ uint32_t _7d0;
+ struct { DECL_BITFIELD(7d0); };
+ };
};
} feat;
@@ -121,7 +145,11 @@ struct cpuid_policy
uint32_t xcr0_low, /* b */:32, /* c */:32, xcr0_high;
/* Subleaf 1. */
- uint32_t Da1, /* b */:32, xss_low, xss_high;
+ union {
+ uint32_t Da1;
+ struct { DECL_BITFIELD(Da1); };
+ };
+ uint32_t /* b */:32, xss_low, xss_high;
};
} xstate;
@@ -133,7 +161,15 @@ struct cpuid_policy
uint32_t max_leaf, /* b */:32, /* c */:32, /* d */:32;
/* Leaf 0x80000001 - Family/model/stepping and features. */
- uint32_t /* a */:32, /* b */:32, e1c, e1d;
+ uint32_t /* a */:32, /* b */:32;
+ union {
+ uint32_t e1c;
+ struct { DECL_BITFIELD(e1c); };
+ };
+ union {
+ uint32_t e1d;
+ struct { DECL_BITFIELD(e1d); };
+ };
uint64_t :64, :64; /* Brand string. */
uint64_t :64, :64; /* Brand string. */
@@ -142,13 +178,26 @@ struct cpuid_policy
uint64_t :64, :64; /* L2/3 cache/TLB. */
/* Leaf 0x80000007 - Advanced Power Management. */
- uint32_t /* a */:32, /* b */:32, /* c */:32, e7d;
+ uint32_t /* a */:32, /* b */:32, /* c */:32;
+ union {
+ uint32_t e7d;
+ struct { DECL_BITFIELD(e7d); };
+ };
/* Leaf 0x80000008 - Misc addr/feature info. */
- uint32_t /* a */:32, e8b, /* c */:32, /* d */:32;
+ uint32_t /* a */:32;
+ union {
+ uint32_t e8b;
+ struct { DECL_BITFIELD(e8b); };
+ };
+ uint32_t /* c */:32, /* d */:32;
};
} extd;
+#undef __DECL_BITFIELD
+#undef _DECL_BITFIELD
+#undef DECL_BITFIELD
+
/* Temporary featureset bitmap. */
uint32_t fs[FSCAPINTS];
};
diff --git a/xen/tools/gen-cpuid.py b/xen/tools/gen-cpuid.py
index 4a673b0..6212e4f 100755
--- a/xen/tools/gen-cpuid.py
+++ b/xen/tools/gen-cpuid.py
@@ -29,6 +29,7 @@ class State(object):
self.pv = []
self.hvm_shadow = []
self.hvm_hap = []
+ self.bitfields = [] # Text to declare named bitfields in C
def parse_definitions(state):
"""
@@ -292,6 +293,28 @@ def crunch_numbers(state):
for k, v in state.deep_deps.iteritems():
state.deep_deps[k] = featureset_to_uint32s(v, nr_entries)
+ # Calculate the bitfield name declarations
+ for word in xrange(nr_entries):
+
+ names = []
+ for bit in xrange(32):
+
+ name = state.names.get(word * 32 + bit, "")
+
+ # Prepend an underscore if the name starts with a digit.
+ if name and name[0] in "0123456789":
+ name = "_" + name
+
+ # Don't generate names for the duplicate features, or ones
+ # fast-forwarded from other state
+ if (name.startswith("E1D_") or
+ name in ("APIC", "OSXSAVE", "OSPKE")):
+ name = ""
+
+ names.append(name.lower())
+
+ state.bitfields.append("bool " + ":1, ".join(names) + ":1")
+
def write_results(state):
state.output.write(
@@ -345,6 +368,15 @@ def write_results(state):
state.output.write(
"""}
+""")
+
+ for idx, text in enumerate(state.bitfields):
+ state.output.write(
+ "#define CPUID_BITFIELD_%d \\\n %s\n\n"
+ % (idx, text))
+
+ state.output.write(
+"""
#endif /* __XEN_X86__FEATURESET_DATA__ */
""")
--
generated by git-patchbot for /home/xen/git/xen.git#master
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