KVM: PPC: Book3S HV: Minor cleanups

* Remove unused kvmppc_vcore::n_busy field.
* Remove setting of RMOR, since it was only used on PPC970 and the
  PPC970 KVM support has been removed.
* Don't use r1 or r2 in setting the runlatch since they are
  conventionally reserved for other things; use r0 instead.
* Streamline the code a little and remove the ext_interrupt_to_host
  label.
* Add some comments about register usage.
* hcall_try_real_mode doesn't need to be global, and can't be
  called from C code anyway.

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

3 files changed, 19 insertions, 28 deletions

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 2f339ff9b851..3eecd8868b01 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -227,7 +227,6 @@ struct kvm_arch {
         unsigned long host_sdr1;
         int tlbie_lock;
         unsigned long lpcr;
-        unsigned long rmor;
         unsigned long vrma_slb_v;
         int hpte_setup_done;
         u32 hpt_order;
@@ -271,7 +270,6 @@ struct kvm_arch {
  */
 struct kvmppc_vcore {
         int n_runnable;
-        int n_busy;
         int num_threads;
         int entry_exit_count;
         int n_woken;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 3fea721f0da5..92ec3fcb3415 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -505,7 +505,6 @@ int main(void)
         DEFINE(KVM_NEED_FLUSH, offsetof(struct kvm, arch.need_tlb_flush.bits));
         DEFINE(KVM_ENABLED_HCALLS, offsetof(struct kvm, arch.enabled_hcalls));
         DEFINE(KVM_LPCR, offsetof(struct kvm, arch.lpcr));
-        DEFINE(KVM_RMOR, offsetof(struct kvm, arch.rmor));
         DEFINE(KVM_VRMA_SLB_V, offsetof(struct kvm, arch.vrma_slb_v));
         DEFINE(VCPU_DSISR, offsetof(struct kvm_vcpu, arch.shregs.dsisr));
         DEFINE(VCPU_DAR, offsetof(struct kvm_vcpu, arch.shregs.dar));
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index b06fe53fd509..f8267e5b3a50 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -245,9 +245,9 @@ kvm_novcpu_exit:
 kvm_start_guest:
 
         /* Set runlatch bit the minute you wake up from nap */
-        mfspr   r1, SPRN_CTRLF
-        ori     r1, r1, 1
-        mtspr   SPRN_CTRLT, r1
+        mfspr   r0, SPRN_CTRLF
+        ori     r0, r0, 1
+        mtspr   SPRN_CTRLT, r0
 
         ld      r2,PACATOC(r13)
 
@@ -493,11 +493,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
         cmpwi   r0,0
         beq     20b
 
-        /* Set LPCR and RMOR. */
+        /* Set LPCR. */
 10:     ld      r8,VCORE_LPCR(r5)
         mtspr   SPRN_LPCR,r8
-        ld      r8,KVM_RMOR(r9)
-        mtspr   SPRN_RMOR,r8
         isync
 
         /* Check if HDEC expires soon */
@@ -1075,7 +1073,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
         bne     2f
         mfspr   r3,SPRN_HDEC
         cmpwi   r3,0
-        bge     ignore_hdec
+        mr      r4,r9
+        bge     fast_guest_return
 2:
         /* See if this is an hcall we can handle in real mode */
         cmpwi   r12,BOOK3S_INTERRUPT_SYSCALL
@@ -1083,26 +1082,21 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 
         /* External interrupt ? */
         cmpwi   r12, BOOK3S_INTERRUPT_EXTERNAL
-        bne+    ext_interrupt_to_host
+        bne+    guest_exit_cont
 
         /* External interrupt, first check for host_ipi. If this is
          * set, we know the host wants us out so let's do it now
          */
         bl      kvmppc_read_intr
         cmpdi   r3, 0
-        bgt     ext_interrupt_to_host
+        bgt     guest_exit_cont
 
         /* 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)
         cmpwi   r0, 0x100
-        bge     ext_interrupt_to_host
-
-        /* Return to guest after delivering any pending interrupt */
         mr      r4, r9
-        b       deliver_guest_interrupt
-
-ext_interrupt_to_host:
+        blt     deliver_guest_interrupt
 
 guest_exit_cont:                /* r9 = vcpu, r12 = trap, r13 = paca */
         /* Save more register state  */
@@ -1763,8 +1757,10 @@ kvmppc_hisi:
  * Returns to the guest if we handle it, or continues on up to
  * the kernel if we can't (i.e. if we don't have a handler for
  * it, or if the handler returns H_TOO_HARD).
+ *
+ * r5 - r8 contain hcall args,
+ * r9 = vcpu, r10 = pc, r11 = msr, r12 = trap, r13 = paca
  */
-        .globl  hcall_try_real_mode
 hcall_try_real_mode:
         ld      r3,VCPU_GPR(R3)(r9)
         andi.   r0,r11,MSR_PR
@@ -2024,10 +2020,6 @@ hcall_real_table:
         .globl  hcall_real_table_end
 hcall_real_table_end:
 
-ignore_hdec:
-        mr      r4,r9
-        b       fast_guest_return
-
 _GLOBAL(kvmppc_h_set_xdabr)
         andi.   r0, r5, DABRX_USER | DABRX_KERNEL
         beq     6f
@@ -2066,7 +2058,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
         li      r3, 0
         blr
 
-_GLOBAL(kvmppc_h_cede)
+_GLOBAL(kvmppc_h_cede)          /* r3 = vcpu pointer, r11 = msr, r13 = paca */
         ori     r11,r11,MSR_EE
         std     r11,VCPU_MSR(r3)
         li      r0,1
@@ -2148,9 +2140,9 @@ _GLOBAL(kvmppc_h_cede)
          * runlatch bit before napping.
          */
 kvm_do_nap:
-        mfspr   r2, SPRN_CTRLF
-        clrrdi  r2, r2, 1
-        mtspr   SPRN_CTRLT, r2
+        mfspr   r0, SPRN_CTRLF
+        clrrdi  r0, r0, 1
+        mtspr   SPRN_CTRLT, r0
 
         li      r0,1
         stb     r0,HSTATE_HWTHREAD_REQ(r13)
@@ -2282,13 +2274,14 @@ machine_check_realmode:
 
 /*
  * Check the reason we woke from nap, and take appropriate action.
- * Returns:
+ * Returns (in r3):
  *      0 if nothing needs to be done
  *      1 if something happened that needs to be handled by the host
  *      -1 if there was a guest wakeup (IPI)
  *
  * Also sets r12 to the interrupt vector for any interrupt that needs
  * to be handled now by the host (0x500 for external interrupt), or zero.
+ * Modifies r0, r6, r7, r8.
  */
 kvmppc_check_wake_reason:
         mfspr   r6, SPRN_SRR1
@@ -2324,6 +2317,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
  *      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)
+ * Modifies r0, r6, r7, r8, returns value in r3.
  */
 kvmppc_read_intr:
         /* see if a host IPI is pending */