KVM: only abort guest entry if timer count goes from 0->1

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Only abort guest entry if the timer count went from 0->1, since for 1->2
or larger the bit will either be set already or a timer irq will have
been injected.

Using atomic_inc_and_test() for it also introduces an SMP barrier
to the LAPIC version (thought it was unecessary because of timer
migration, but guest can be scheduled to a different pCPU between exit
and kvm_vcpu_block(), so there is the possibility for a race).

Noticed by Avi.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

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This commit is contained in:

Marcelo Tosatti 2008-06-11 19:52:53 -03:00 • committed by Avi Kivity

parent 7f39f8ac17

commit 622395a9e6

2 changed files with 6 additions and 9 deletions

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11

arch/x86/kvm/i8254.c

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4

arch/x86/kvm/lapic.c

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