[Xen-changelog] [xen master] x86/cpuid: Remove BUG_ON() condition from guest_cpuid()

[patchbot@xxxxxxx]

commit 2073a26f8920ac9c26323122308873d0bcc84be1
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Jan 17 11:44:29 2017 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri Jan 20 16:12:10 2017 +0000

    x86/cpuid: Remove BUG_ON() condition from guest_cpuid()
    
    Include a min() against the appropriate ARRAY_SIZE(), and ASSERT() that
    max_subleaf is within ARRAY_SIZE().
    
    This is more robust to unexpected problems in a release build of Xen.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Doug Goldstein <cardoe@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpuid.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index 7b9af1b..076fab3 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -856,10 +856,11 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
         switch ( leaf )
         {
         case 0x7:
-            if ( subleaf > p->feat.max_subleaf )
+            ASSERT(p->feat.max_subleaf < ARRAY_SIZE(p->feat.raw));
+            if ( subleaf > min_t(uint32_t, p->feat.max_subleaf,
+                                 ARRAY_SIZE(p->feat.raw) - 1) )
                 return;
 
-            BUG_ON(subleaf >= ARRAY_SIZE(p->feat.raw));
             *res = p->feat.raw[subleaf];
             break;
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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