1 files changed, 13 insertions, 10 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index bc8de75b1925..be4fa04a37c9 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -153,7 +153,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 
 13:     b       machine_check_fwnmi
 
-
 /*
  * We come in here when wakened from nap mode on a secondary hw thread.
  * Relocation is off and most register values are lost.
@@ -224,6 +223,11 @@ kvm_start_guest:
         /* Clear our vcpu pointer so we don't come back in early */
         li      r0, 0
         std     r0, HSTATE_KVM_VCPU(r13)
+        /*
+         * Make sure we clear HSTATE_KVM_VCPU(r13) before incrementing
+         * the nap_count, because once the increment to nap_count is
+         * visible we could be given another vcpu.
+         */
         lwsync
         /* Clear any pending IPI - we're an offline thread */
         ld      r5, HSTATE_XICS_PHYS(r13)
@@ -241,7 +245,6 @@ kvm_start_guest:
         /* increment the nap count and then go to nap mode */
         ld      r4, HSTATE_KVM_VCORE(r13)
         addi    r4, r4, VCORE_NAP_COUNT
-        lwsync                          /* make previous updates visible */
 51:     lwarx   r3, 0, r4
         addi    r3, r3, 1
         stwcx.  r3, 0, r4
@@ -751,15 +754,14 @@ kvmppc_interrupt_hv:
          * guest CR, R12 saved in shadow VCPU SCRATCH1/0
          * guest R13 saved in SPRN_SCRATCH0
          */
-        /* abuse host_r2 as third scratch area; we get r2 from PACATOC(r13) */
-        std     r9, HSTATE_HOST_R2(r13)
+        std     r9, HSTATE_SCRATCH2(r13)
 
         lbz     r9, HSTATE_IN_GUEST(r13)
         cmpwi   r9, KVM_GUEST_MODE_HOST_HV
         beq     kvmppc_bad_host_intr
 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
         cmpwi   r9, KVM_GUEST_MODE_GUEST
-        ld      r9, HSTATE_HOST_R2(r13)
+        ld      r9, HSTATE_SCRATCH2(r13)
         beq     kvmppc_interrupt_pr
 #endif
         /* We're now back in the host but in guest MMU context */
@@ -779,7 +781,7 @@ kvmppc_interrupt_hv:
         std     r6, VCPU_GPR(R6)(r9)
         std     r7, VCPU_GPR(R7)(r9)
         std     r8, VCPU_GPR(R8)(r9)
-        ld      r0, HSTATE_HOST_R2(r13)
+        ld      r0, HSTATE_SCRATCH2(r13)
         std     r0, VCPU_GPR(R9)(r9)
         std     r10, VCPU_GPR(R10)(r9)
         std     r11, VCPU_GPR(R11)(r9)
@@ -990,14 +992,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
          */
         /* Increment the threads-exiting-guest count in the 0xff00
            bits of vcore->entry_exit_count */
-        lwsync
         ld      r5,HSTATE_KVM_VCORE(r13)
         addi    r6,r5,VCORE_ENTRY_EXIT
 41:     lwarx   r3,0,r6
         addi    r0,r3,0x100
         stwcx.  r0,0,r6
         bne     41b
-        lwsync
+        isync           /* order stwcx. vs. reading napping_threads */
 
         /*
          * At this point we have an interrupt that we have to pass
@@ -1030,6 +1031,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
         sld     r0,r0,r4
         andc.   r3,r3,r0                /* no sense IPI'ing ourselves */
         beq     43f
+        /* Order entry/exit update vs. IPIs */
+        sync
         mulli   r4,r4,PACA_SIZE         /* get paca for thread 0 */
         subf    r6,r4,r13
 42:     andi.   r0,r3,1
@@ -1638,10 +1641,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206)
         bge     kvm_cede_exit
         stwcx.  r4,0,r6
         bne     31b
+        /* order napping_threads update vs testing entry_exit_count */
+        isync
         li      r0,1
         stb     r0,HSTATE_NAPPING(r13)
-        /* order napping_threads update vs testing entry_exit_count */
-        lwsync
         mr      r4,r3
         lwz     r7,VCORE_ENTRY_EXIT(r5)
         cmpwi   r7,0x100