[PATCH 29/30] KVM: PPC: bookehv: disable MAS register updates early
From: Alexander Graf <hidden>
Date: 2012-02-17 17:14:12
Also in:
linuxppc-dev
Subsystem:
kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted> --- arch/powerpc/kvm/bookehv_interrupts.S | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S
index 8a297c3..7d558a8 100644
--- a/arch/powerpc/kvm/bookehv_interrupts.S
+++ b/arch/powerpc/kvm/bookehv_interrupts.S@@ -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
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1.6.0.2