KVM: x86: fix root cause for missed hardware breakpoints

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commit 70e4da7a8f upstream.

Commit 172b2386ed ("KVM: x86: fix missed hardware breakpoints",
2016-02-10) worked around a case where the debug registers are not loaded
correctly on preemption and on the first entry to KVM_RUN.

However, Xiao Guangrong pointed out that the root cause must be that
KVM_DEBUGREG_BP_ENABLED is not being set correctly.  This can indeed
happen due to the lazy debug exit mechanism, which does not call
kvm_update_dr7.  Fix it by replacing the existing loop (more or less
equivalent to kvm_update_dr0123) with calls to all the kvm_update_dr*
functions.

Fixes: 172b2386ed
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Paolo Bonzini 2016-02-26 12:28:40 +01:00 • committed by Greg Kroah-Hartman

parent 7931825da8

commit 25e8618619

1 changed files with 4 additions and 5 deletions

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arch/x86/kvm/x86.c

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