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: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S
index 2d1f56c..57e2fa4 100644
--- a/arch/powerpc/kvm/bookehv_interrupts.S
+++ b/arch/powerpc/kvm/bookehv_interrupts.S
@@ -49,7 +49,8 @@
* kernel with the -ffixed-r2 gcc option.
*/
#define HOST_R2 (3 * LONGBYTES)
-#define HOST_NV_GPRS (4 * LONGBYTES)
+#define HOST_CR (4 * LONGBYTES)
+#define HOST_NV_GPRS (5 * LONGBYTES)
#define HOST_NV_GPR(n) (HOST_NV_GPRS + ((n - 14) * LONGBYTES))
#define HOST_MIN_STACK_SIZE (HOST_NV_GPR(31) + LONGBYTES)
#define HOST_STACK_SIZE ((HOST_MIN_STACK_SIZE + 15) & ~15) /* Align. */
@@ -396,6 +397,7 @@
heavyweight_exit:
/* Not returning to guest. */
PPC_LL r5, HOST_STACK_LR(r1)
+ lwz r6, HOST_CR(r1)
/*
* We already saved guest volatile register state; now save the
@@ -442,6 +444,7 @@
/* Return to kvm_vcpu_run(). */
mtlr r5
+ mtcr r6
addi r1, r1, HOST_STACK_SIZE
/* r3 still contains the return code from kvmppc_handle_exit(). */
blr
@@ -457,8 +460,11 @@
/* Save host state to stack. */
PPC_STL r3, HOST_RUN(r1)
mflr r3
+ mfcr r5
PPC_STL r3, HOST_STACK_LR(r1)
+ stw r5, HOST_CR(r1)
+
/* Save host non-volatile register state to stack. */
PPC_STL r14, HOST_NV_GPR(r14)(r1)
PPC_STL r15, HOST_NV_GPR(r15)(r1)