KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine

This moves the code in book3s_hv_rmhandlers.S that reads any pending
interrupt from the XICS interrupt controller, and works out whether
it is an IPI for the guest, an IPI for the host, or a device interrupt,
into a new function called kvmppc_read_intr.  Later patches will
need this.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 2bf2951..c91ae2b 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -862,46 +862,11 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206)
         * set, we know the host wants us out so let's do it now
         */
 do_ext_interrupt:
-       lbz     r0, HSTATE_HOST_IPI(r13)
-       cmpwi   r0, 0
-       bne     ext_interrupt_to_host
-
-       /* Now read the interrupt from the ICP */
-       ld      r5, HSTATE_XICS_PHYS(r13)
-       li      r7, XICS_XIRR
-       cmpdi   r5, 0
-       beq-    ext_interrupt_to_host
-       lwzcix  r3, r5, r7
-       rlwinm. r0, r3, 0, 0xffffff
-       sync
-       beq     3f              /* if nothing pending in the ICP */
-
-       /* We found something in the ICP...
-        *
-        * If it's not an IPI, stash it in the PACA and return to
-        * the host, we don't (yet) handle directing real external
-        * interrupts directly to the guest
-        */
-       cmpwi   r0, XICS_IPI
-       bne     ext_stash_for_host
-
-       /* It's an IPI, clear the MFRR and EOI it */
-       li      r0, 0xff
-       li      r6, XICS_MFRR
-       stbcix  r0, r5, r6              /* clear the IPI */
-       stwcix  r3, r5, r7              /* EOI it */
-       sync
-
-       /* We need to re-check host IPI now in case it got set in the
-        * meantime. If it's clear, we bounce the interrupt to the
-        * guest
-        */
-       lbz     r0, HSTATE_HOST_IPI(r13)
-       cmpwi   r0, 0
-       bne-    1f
+       bl      kvmppc_read_intr
+       cmpdi   r3, 0
+       bgt     ext_interrupt_to_host
 
        /* Allright, looks like an IPI for the guest, we need to set MER */
-3:
        /* Check if any CPU is heading out to the host, if so head out too */
        ld      r5, HSTATE_KVM_VCORE(r13)
        lwz     r0, VCORE_ENTRY_EXIT(r5)
@@ -930,17 +895,6 @@ do_ext_interrupt:
        mtspr   SPRN_LPCR, r8
        b       fast_guest_return
 
-       /* We raced with the host, we need to resend that IPI, bummer */
-1:     li      r0, IPI_PRIORITY
-       stbcix  r0, r5, r6              /* set the IPI */
-       sync
-       b       ext_interrupt_to_host
-
-ext_stash_for_host:
-       /* It's not an IPI and it's for the host, stash it in the PACA
-        * before exit, it will be picked up by the host ICP driver
-        */
-       stw     r3, HSTATE_SAVED_XIRR(r13)
 ext_interrupt_to_host:
 
 guest_exit_cont:               /* r9 = vcpu, r12 = trap, r13 = paca */
@@ -1816,6 +1770,71 @@ machine_check_realmode:
        b       fast_interrupt_c_return
 
 /*
+ * Determine what sort of external interrupt is pending (if any).
+ * Returns:
+ *     0 if no interrupt is pending
+ *     1 if an interrupt is pending that needs to be handled by the host
+ *     -1 if there was a guest wakeup IPI (which has now been cleared)
+ */
+kvmppc_read_intr:
+       /* see if a host IPI is pending */
+       li      r3, 1
+       lbz     r0, HSTATE_HOST_IPI(r13)
+       cmpwi   r0, 0
+       bne     1f
+
+       /* Now read the interrupt from the ICP */
+       ld      r6, HSTATE_XICS_PHYS(r13)
+       li      r7, XICS_XIRR
+       cmpdi   r6, 0
+       beq-    1f
+       lwzcix  r0, r6, r7
+       rlwinm. r3, r0, 0, 0xffffff
+       sync
+       beq     1f                      /* if nothing pending in the ICP */
+
+       /* We found something in the ICP...
+        *
+        * If it's not an IPI, stash it in the PACA and return to
+        * the host, we don't (yet) handle directing real external
+        * interrupts directly to the guest
+        */
+       cmpwi   r3, XICS_IPI            /* if there is, is it an IPI? */
+       li      r3, 1
+       bne     42f
+
+       /* It's an IPI, clear the MFRR and EOI it */
+       li      r3, 0xff
+       li      r8, XICS_MFRR
+       stbcix  r3, r6, r8              /* clear the IPI */
+       stwcix  r0, r6, r7              /* EOI it */
+       sync
+
+       /* We need to re-check host IPI now in case it got set in the
+        * meantime. If it's clear, we bounce the interrupt to the
+        * guest
+        */
+       lbz     r0, HSTATE_HOST_IPI(r13)
+       cmpwi   r0, 0
+       bne-    43f
+
+       /* OK, it's an IPI for us */
+       li      r3, -1
+1:     blr
+
+42:    /* It's not an IPI and it's for the host, stash it in the PACA
+        * before exit, it will be picked up by the host ICP driver
+        */
+       stw     r0, HSTATE_SAVED_XIRR(r13)
+       b       1b
+
+43:    /* We raced with the host, we need to resend that IPI, bummer */
+       li      r0, IPI_PRIORITY
+       stbcix  r0, r6, r8              /* set the IPI */
+       sync
+       b       1b
+
+/*
  * Save away FP, VMX and VSX registers.
  * r3 = vcpu pointer
  */