KVM: PPC: Call SLB patching code in interrupt safe manner

[deliverable/linux.git] / arch / powerpc / kvm / book3s_64_rmhandlers.S

diff --git a/arch/powerpc/kvm/book3s_64_rmhandlers.S b/arch/powerpc/kvm/book3s_64_rmhandlers.S
index fb7dd2e9ac8863fdfc48be3088cd73dcb6337df4..e7091c9459a8b599a5c8c96e61e25ac0d20087ea 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_64_rmhandlers.S
@@ -45,36 +45,25 @@ kvmppc_trampoline_\intno:
         * 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
+       cmpwi   r12, KVM_GUEST_MODE_NONE
        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)
+       /* Should we just skip the faulting instruction? */
+       cmpwi   r12, KVM_GUEST_MODE_SKIP
+       beq     kvmppc_handler_skip_ins
 
        /* Let's store which interrupt we're handling */
        li      r12, \intno
@@ -101,24 +90,74 @@ INTERRUPT_TRAMPOLINE       BOOK3S_INTERRUPT_PERFMON
 INTERRUPT_TRAMPOLINE   BOOK3S_INTERRUPT_ALTIVEC
 INTERRUPT_TRAMPOLINE   BOOK3S_INTERRUPT_VSX
 
+/*
+ * Bring us back to the faulting code, but skip the
+ * faulting instruction.
+ *
+ * This is a generic exit path from the interrupt
+ * trampolines above.
+ *
+ * Input Registers:
+ *
+ * R12               = free
+ * R13               = PACA
+ * PACA.KVM.SCRATCH0 = guest R12
+ * PACA.KVM.SCRATCH1 = guest CR
+ * SPRG_SCRATCH0     = guest R13
+ *
+ */
+kvmppc_handler_skip_ins:
+
+       /* Patch the IP to the next instruction */
+       mfsrr0  r12
+       addi    r12, r12, 4
+       mtsrr0  r12
+
+       /* Clean up all state */
+       lwz     r12, PACA_KVM_SCRATCH1(r13)
+       mtcr    r12
+       ld      r12, PACA_KVM_SCRATCH0(r13)
+       mfspr   r13, SPRN_SPRG_SCRATCH0
+
+       /* And get back into the code */
+       RFI
+
 /*
  * This trampoline brings us back to a real mode handler
  *
  * 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:
 
+/*
+ * Call a function in real mode
+ *
+ * Input Registers:
+ *
+ * R3 = function
+ * R4 = MSR
+ * R5 = CTR
+ *
+ */
+_GLOBAL(kvmppc_rmcall)
+       mtmsr   r4              /* Disable relocation, so mtsrr
+                                  doesn't get interrupted */
+       mtctr   r5
+       mtsrr0  r3
+       mtsrr1  r4
+       RFI
+
 .global kvmppc_trampoline_lowmem
 kvmppc_trampoline_lowmem:
        .long kvmppc_handler_lowmem_trampoline - _stext