KVM: PPC: Save/Restore CR over vcpu_run
On PPC, CR2-CR4 are nonvolatile, thus have to be saved across function calls.
We didn't respect that for any architecture until Paul spotted it in his
patch for Book3S-HV. This patch saves/restores CR for all KVM capable PPC hosts.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index 10d8ef6..c8c4b87 100644
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -34,7 +34,8 @@
/* r2 is special: it holds 'current', and it made nonvolatile in the
* kernel with the -ffixed-r2 gcc option. */
#define HOST_R2 12
-#define HOST_NV_GPRS 16
+#define HOST_CR 16
+#define HOST_NV_GPRS 20
#define HOST_NV_GPR(n) (HOST_NV_GPRS + ((n - 14) * 4))
#define HOST_MIN_STACK_SIZE (HOST_NV_GPR(31) + 4)
#define HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
@@ -296,8 +297,10 @@
/* Return to kvm_vcpu_run(). */
lwz r4, HOST_STACK_LR(r1)
+ lwz r5, HOST_CR(r1)
addi r1, r1, HOST_STACK_SIZE
mtlr r4
+ mtcr r5
/* r3 still contains the return code from kvmppc_handle_exit(). */
blr
@@ -314,6 +317,8 @@
stw r3, HOST_RUN(r1)
mflr r3
stw r3, HOST_STACK_LR(r1)
+ mfcr r5
+ stw r5, HOST_CR(r1)
/* Save host non-volatile register state to stack. */
stw r14, HOST_NV_GPR(r14)(r1)