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/book3s_interrupts.S b/arch/powerpc/kvm/book3s_interrupts.S
index 0a8515a..3e35383 100644 (file)
--- a/arch/powerpc/kvm/book3s_interrupts.S
+++ b/arch/powerpc/kvm/book3s_interrupts.S
@@ -84,6 +84,10 @@ kvm_start_entry:
        /* Save non-volatile registers (r14 - r31) */
        SAVE_NVGPRS(r1)
 
+       /* Save CR */
+       mfcr    r14
+       stw     r14, _CCR(r1)
+
        /* Save LR */
        PPC_STL r0, _LINK(r1)
 
@@ -165,6 +169,9 @@ kvm_exit_loop:
        PPC_LL  r4, _LINK(r1)
        mtlr    r4
 
+       lwz     r14, _CCR(r1)
+       mtcr    r14
+
        /* Restore non-volatile host registers (r14 - r31) */
        REST_NVGPRS(r1)
 

diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index 10d8ef6..c8c4b87 100644 (file)
--- 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 @@ heavyweight_exit:
 
        /* 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 @@ _GLOBAL(__kvmppc_vcpu_run)
        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)