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| H A D | step.c | diff 4ba51fd75cc3789be83f0d6f878dabbb0cb19bca Thu Apr 03 16:18:55 CDT 2008 Roland McGrath <roland@redhat.com> x86 ptrace: avoid unnecessary wrmsr
This avoids using wrmsr on MSR_IA32_DEBUGCTLMSR when it's not needed.
No wrmsr ever needs to be done if noone has ever used block stepping.
Without this change, using ptrace on 2.6.25 on an x86 KVM guest
will tickle KVM's missing support for the MSR and crash the guest
kernel. Though host KVM is the buggy one, this makes for a regression
in the guest behavior from 2.6.24->2.6.25 that we can easily avoid.
I also corrected some bad whitespace.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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