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 (file)
--- 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 @@ skip_nv_load:
 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 @@ heavyweight_exit:
 
        /* 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 @@ _GLOBAL(__kvmppc_vcpu_run)
        /* 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)