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KVM: PPC: bookehv: disable MAS register updates early

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We need to make sure that no MAS updates happen automatically while we
have the guest MAS registers loaded. So move the disabling code a bit
higher up so that it covers the full time we have guest values in MAS
registers.

The race this patch fixes should never occur, but it makes the code a
bit more logical to do it this way around.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Alexander Graf 2012-02-16 14:53:04 +00:00 committed by Avi Kivity
parent 8a3da55784
commit e9ba39c1f3
1 changed files with 6 additions and 4 deletions
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10
arch/powerpc/kvm/bookehv_interrupts.S
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@ -358,6 +358,7 @@ _GLOBAL(kvmppc_resume_host)
mtspr SPRN_MAS4, r6
stw r5, VCPU_SHARED_MAS7_3+0(r11)
mtspr SPRN_MAS6, r8
/* Enable MAS register updates via exception */
mfspr r3, SPRN_EPCR
rlwinm r3, r3, 0, ~SPRN_EPCR_DMIUH
mtspr SPRN_EPCR, r3
@ -515,6 +516,11 @@ lightweight_exit:
mtspr SPRN_PID, r3
PPC_LL r11, VCPU_SHARED(r4)
/* Disable MAS register updates via exception */
mfspr r3, SPRN_EPCR
oris r3, r3, SPRN_EPCR_DMIUH@h
mtspr SPRN_EPCR, r3
isync
/* Save host mas4 and mas6 and load guest MAS registers */
mfspr r3, SPRN_MAS4
stw r3, VCPU_HOST_MAS4(r4)
@ -538,10 +544,6 @@ lightweight_exit:
lwz r5, VCPU_SHARED_MAS7_3+0(r11)
mtspr SPRN_MAS6, r3
mtspr SPRN_MAS7, r5
/* Disable MAS register updates via exception */
mfspr r3, SPRN_EPCR
oris r3, r3, SPRN_EPCR_DMIUH@h
mtspr SPRN_EPCR, r3
/*
* Host interrupt handlers may have clobbered these guest-readable