[PATCH 43/56] KVM: PPC: Save/Restore CR over vcpu_run

Alexander Graf
2012-03-15T12:11:12Z

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>
---
arch/powerpc/kvm/book3s_interrupts.S | 7 +++++++
arch/powerpc/kvm/booke_interrupts.S | 7 ++++++-
arch/powerpc/kvm/bookehv_interrupts.S | 8 +++++++-
3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_interrupts.S b/arch/powerpc/kvm/book3s_interrupts.S
index 0a8515a..3e35383 100644
--- 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
--- 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)
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 @@ 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)
--
1.6.0.2