diff options
| author | Bharat Bhushan <r65777@freescale.com> | 2011-10-13 15:17:08 +0530 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-03-05 14:52:24 +0200 |
| commit | f9208427f72e6cb52c71767af3bf8c14c43c27ac (patch) | |
| tree | 051bd94371fa20d83848237a9a89ff6670a4b466 /arch/powerpc/kernel | |
| parent | 95325e6b190bb4ec3383aa1241d10675057bff45 (diff) | |
PPC: Fix race in mtmsr paravirt implementation
The current implementation of mtmsr and mtmsrd are racy in that it does:
* check (int_pending == 0)
---> host sets int_pending = 1 <---
* write shared page
* done
while instead we should check for int_pending after the shared page is written.
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/kvm_emul.S | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S index f2b1b2523e6..3d64c5704fd 100644 --- a/arch/powerpc/kernel/kvm_emul.S +++ b/arch/powerpc/kernel/kvm_emul.S @@ -167,6 +167,9 @@ maybe_stay_in_guest: kvm_emulate_mtmsr_reg2: ori r30, r0, 0 + /* Put MSR into magic page because we don't call mtmsr */ + STL64(r30, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0) + /* Check if we have to fetch an interrupt */ lwz r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0) cmpwi r31, 0 @@ -174,15 +177,10 @@ kvm_emulate_mtmsr_reg2: /* Check if we may trigger an interrupt */ andi. r31, r30, MSR_EE - beq no_mtmsr - - b do_mtmsr + bne do_mtmsr no_mtmsr: - /* Put MSR into magic page because we don't call mtmsr */ - STL64(r30, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0) - SCRATCH_RESTORE /* Go back to caller */ |