KVM: PPC: Book3S HV: Save/restore XER in checkpointed register state
When switching from/to a guest that has a transaction in progress,
we need to save/restore the checkpointed register state. Although
XER is part of the CPU state that gets checkpointed, the code that
does this saving and restoring doesn't save/restore XER.
This fixes it by saving and restoring the XER. To allow userspace
to read/write the checkpointed XER value, we also add a new ONE_REG
specifier.
The visible effect of this bug is that the guest may see its XER
value being corrupted when it uses transactions.
Fixes: e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support")
Fixes: 0a8eccefcb34 ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index c3c1d1b..6f81adb 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -2600,11 +2600,13 @@
mfctr r7
mfspr r8, SPRN_AMR
mfspr r10, SPRN_TAR
+ mfxer r11
std r5, VCPU_LR_TM(r9)
stw r6, VCPU_CR_TM(r9)
std r7, VCPU_CTR_TM(r9)
std r8, VCPU_AMR_TM(r9)
std r10, VCPU_TAR_TM(r9)
+ std r11, VCPU_XER_TM(r9)
/* Restore r12 as trap number. */
lwz r12, VCPU_TRAP(r9)
@@ -2697,11 +2699,13 @@
ld r7, VCPU_CTR_TM(r4)
ld r8, VCPU_AMR_TM(r4)
ld r9, VCPU_TAR_TM(r4)
+ ld r10, VCPU_XER_TM(r4)
mtlr r5
mtcr r6
mtctr r7
mtspr SPRN_AMR, r8
mtspr SPRN_TAR, r9
+ mtxer r10
/*
* Load up PPR and DSCR values but don't put them in the actual SPRs
