KVM: PPC: Use PACA backed shadow vcpu
We're being horribly racy right now. All the entry and exit code hijacks
random fields from the PACA that could easily be used by different code in
case we get interrupted, for example by a #MC or even page fault.
After discussing this with Ben, we figured it's best to reserve some more
space in the PACA and just shove off some vcpu state to there.
That way we can drastically improve the readability of the code, make it
less racy and less complex.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_64_rmhandlers.S b/arch/powerpc/kvm/book3s_64_rmhandlers.S
index fb7dd2e..cd9f0b6 100644
--- a/arch/powerpc/kvm/book3s_64_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_64_rmhandlers.S
@@ -45,37 +45,21 @@
* To distinguish, we check a magic byte in the PACA
*/
mfspr r13, SPRN_SPRG_PACA /* r13 = PACA */
- std r12, (PACA_EXMC + EX_R12)(r13)
+ std r12, PACA_KVM_SCRATCH0(r13)
mfcr r12
- stw r12, (PACA_EXMC + EX_CCR)(r13)
+ stw r12, PACA_KVM_SCRATCH1(r13)
lbz r12, PACA_KVM_IN_GUEST(r13)
cmpwi r12, 0
bne ..kvmppc_handler_hasmagic_\intno
/* No KVM guest? Then jump back to the Linux handler! */
- lwz r12, (PACA_EXMC + EX_CCR)(r13)
+ lwz r12, PACA_KVM_SCRATCH1(r13)
mtcr r12
- ld r12, (PACA_EXMC + EX_R12)(r13)
+ ld r12, PACA_KVM_SCRATCH0(r13)
mfspr r13, SPRN_SPRG_SCRATCH0 /* r13 = original r13 */
b kvmppc_resume_\intno /* Get back original handler */
/* Now we know we're handling a KVM guest */
..kvmppc_handler_hasmagic_\intno:
- /* Unset guest state */
- li r12, 0
- stb r12, PACA_KVM_IN_GUEST(r13)
-
- std r1, (PACA_EXMC+EX_R9)(r13)
- std r10, (PACA_EXMC+EX_R10)(r13)
- std r11, (PACA_EXMC+EX_R11)(r13)
- std r2, (PACA_EXMC+EX_R13)(r13)
-
- mfsrr0 r10
- mfsrr1 r11
-
- /* Restore R1/R2 so we can handle faults */
- ld r1, PACAR1(r13)
- ld r2, (PACA_EXMC+EX_SRR0)(r13)
-
/* Let's store which interrupt we're handling */
li r12, \intno
@@ -106,16 +90,16 @@
*
* Input Registers:
*
- * R6 = SRR0
- * R7 = SRR1
+ * R5 = SRR0
+ * R6 = SRR1
* LR = real-mode IP
*
*/
.global kvmppc_handler_lowmem_trampoline
kvmppc_handler_lowmem_trampoline:
- mtsrr0 r6
- mtsrr1 r7
+ mtsrr0 r5
+ mtsrr1 r6
blr
kvmppc_handler_lowmem_trampoline_end: