[PATCH 42/56] KVM: PPC: Book3S HV: Save and restore CR in __kvmppc_vcore_entry

Alexander Graf
2012-03-15T12:11:11Z

From: Paul Mackerras <paulus@samba.org>

The ABI specifies that CR fields CR2--CR4 are nonvolatile across function
calls. Currently __kvmppc_vcore_entry doesn't save and restore the CR,
leading to CR2--CR4 getting corrupted with guest values, possibly leading
to incorrect behaviour in its caller. This adds instructions to save
and restore CR at the points where we save and restore the nonvolatile
GPRs.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/kvm/book3s_hv_interrupts.S | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_interrupts.S b/arch/powerpc/kvm/book3s_hv_interrupts.S
index 3f7b674..d3fb4df 100644
--- a/arch/powerpc/kvm/book3s_hv_interrupts.S
+++ b/arch/powerpc/kvm/book3s_hv_interrupts.S
@@ -46,8 +46,10 @@ _GLOBAL(__kvmppc_vcore_entry)
/* Save host state to the stack */
stdu r1, -SWITCH_FRAME_SIZE(r1)

- /* Save non-volatile registers (r14 - r31) */
+ /* Save non-volatile registers (r14 - r31) and CR */
SAVE_NVGPRS(r1)
+ mfcr r3
+ std r3, _CCR(r1)

/* Save host DSCR */
BEGIN_FTR_SECTION
@@ -157,8 +159,10 @@ kvmppc_handler_highmem:
* R13 = PACA
*/

- /* Restore non-volatile host registers (r14 - r31) */
+ /* Restore non-volatile host registers (r14 - r31) and CR */
REST_NVGPRS(r1)
+ ld r4, _CCR(r1)
+ mtcr r4

addi r1, r1, SWITCH_FRAME_SIZE
ld r0, PPC_LR_STKOFF(r1)
--
1.6.0.2