[xen stable-4.7] x86: Fix "x86: further CPUID handling adjustments"
Author: Andrew Cooper <[hidden email]>
AuthorDate: Tue May 29 10:23:47 2018 +0200
Commit: Jan Beulich <[hidden email]>
CommitDate: Tue May 29 10:23:47 2018 +0200
x86: Fix "x86: further CPUID handling adjustments"
c/s 62b187969 "x86: further CPUID handling adjustments" make some adjustments.
However, it breaks levelling of guests, making it impossible for the toolstack
to hide STIBP or IBPB from guests on hardware with up-to-date microcode.
The dom0 issue referenced in the commit message was fixed by the hunk
adjusting the zeroing alone. STIBP and IBPB don't need (and indeed, must not
be for levelling purposes) OR'd into the leaf.
Signed-off-by: Andrew Cooper <[hidden email]>
Reviewed-by: Jan Beulich <[hidden email]>
xen/arch/x86/hvm/hvm.c | 3 ---
xen/arch/x86/traps.c | 3 ---
2 files changed, 6 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index ff1c6fa59a..f62b021c5e 100644
@@ -3496,8 +3496,6 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx,