[Xen-changelog] [xen staging] libx86/CPUID: fix (not just) leaf 7 processing

[patchbot@xxxxxxx]

commit eb0bad81fceb3e81df5f73441771b49b732edf56
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Mar 27 11:40:59 2020 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Mar 27 11:40:59 2020 +0100

    libx86/CPUID: fix (not just) leaf 7 processing
    
    For one, subleaves within the respective union shouldn't live in
    separate sub-structures. And then x86_cpuid_policy_fill_native() should,
    as it did originally, iterate over all subleaves here as well as over
    all main leaves. Switch to using a "<= MIN()"-based approach similar to
    that used in x86_cpuid_copy_to_buffer(). Also follow this for the
    extended main leaves then.
    
    Fixes: 1bd2b750537b ("libx86: Fix 32bit stubdom build of 
x86_cpuid_policy_fill_native()")
    Fixes: 97e4ebdcd765 ("x86/CPUID: support leaf 7 subleaf 1 / AVX512_BF16")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/include/xen/lib/x86/cpuid.h |  3 +--
 xen/lib/x86/cpuid.c             | 12 ++++++------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/xen/include/xen/lib/x86/cpuid.h b/xen/include/xen/lib/x86/cpuid.h
index 331ef4f4f0..f4ef8a9f2f 100644
--- a/xen/include/xen/lib/x86/cpuid.h
+++ b/xen/include/xen/lib/x86/cpuid.h
@@ -181,8 +181,7 @@ struct cpuid_policy
                 uint32_t _7d0;
                 struct { DECL_BITFIELD(7d0); };
             };
-        };
-        struct {
+
             /* Subleaf 1. */
             union {
                 uint32_t _7a1;
diff --git a/xen/lib/x86/cpuid.c b/xen/lib/x86/cpuid.c
index 76b8511034..c111d43b00 100644
--- a/xen/lib/x86/cpuid.c
+++ b/xen/lib/x86/cpuid.c
@@ -71,8 +71,8 @@ void x86_cpuid_policy_fill_native(struct cpuid_policy *p)
     unsigned int i;
 
     cpuid_leaf(0, &p->basic.raw[0]);
-    for ( i = 1; i < min_t(unsigned int, ARRAY_SIZE(p->basic.raw),
-                           p->basic.max_leaf); ++i )
+    for ( i = 1; i <= MIN(p->basic.max_leaf,
+                          ARRAY_SIZE(p->basic.raw) - 1); ++i )
     {
         switch ( i )
         {
@@ -116,8 +116,8 @@ void x86_cpuid_policy_fill_native(struct cpuid_policy *p)
     {
         cpuid_count_leaf(7, 0, &p->feat.raw[0]);
 
-        for ( i = 1; i < min_t(unsigned int, ARRAY_SIZE(p->feat.raw),
-                               p->feat.max_subleaf); ++i )
+        for ( i = 1; i <= MIN(p->feat.max_subleaf,
+                              ARRAY_SIZE(p->feat.raw) - 1); ++i )
             cpuid_count_leaf(7, i, &p->feat.raw[i]);
     }
 
@@ -172,8 +172,8 @@ void x86_cpuid_policy_fill_native(struct cpuid_policy *p)
 
     /* Extended leaves. */
     cpuid_leaf(0x80000000, &p->extd.raw[0]);
-    for ( i = 1; i < min_t(unsigned int, ARRAY_SIZE(p->extd.raw),
-                           p->extd.max_leaf + 1 - 0x80000000); ++i )
+    for ( i = 1; i <= MIN(p->extd.max_leaf & 0xffffU,
+                          ARRAY_SIZE(p->extd.raw) - 1); ++i )
         cpuid_leaf(0x80000000 + i, &p->extd.raw[i]);
 
     x86_cpuid_policy_recalc_synth(p);
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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