Merge tag 'kvm-ppc-fixes-4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master

Fix for PPC KVM for 4.16

- Fix bug leading to lost IPIs on POWER9 and hence to other CPUs reporting
  lockups in smp_call_function_many().

1 files changed, 5 insertions, 5 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index f31f357b8c5a..d33264697a31 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -320,7 +320,6 @@ kvm_novcpu_exit:
         stw     r12, STACK_SLOT_TRAP(r1)
         bl      kvmhv_commence_exit
         nop
-        lwz     r12, STACK_SLOT_TRAP(r1)
         b       kvmhv_switch_to_host
 
 /*
@@ -1220,6 +1219,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 
 secondary_too_late:
         li      r12, 0
+        stw     r12, STACK_SLOT_TRAP(r1)
         cmpdi   r4, 0
         beq     11f
         stw     r12, VCPU_TRAP(r4)
@@ -1558,12 +1558,12 @@ mc_cont:
 3:      stw     r5,VCPU_SLB_MAX(r9)
 
 guest_bypass:
+        stw     r12, STACK_SLOT_TRAP(r1)
         mr      r3, r12
         /* Increment exit count, poke other threads to exit */
         bl      kvmhv_commence_exit
         nop
         ld      r9, HSTATE_KVM_VCPU(r13)
-        lwz     r12, VCPU_TRAP(r9)
 
         /* Stop others sending VCPU interrupts to this physical CPU */
         li      r0, -1
@@ -1898,6 +1898,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_POWER9_DD1)
          * POWER7/POWER8 guest -> host partition switch code.
          * We don't have to lock against tlbies but we do
          * have to coordinate the hardware threads.
+         * Here STACK_SLOT_TRAP(r1) contains the trap number.
          */
 kvmhv_switch_to_host:
         /* Secondary threads wait for primary to do partition switch */
@@ -1950,12 +1951,12 @@ BEGIN_FTR_SECTION
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 
         /* If HMI, call kvmppc_realmode_hmi_handler() */
+        lwz     r12, STACK_SLOT_TRAP(r1)
         cmpwi   r12, BOOK3S_INTERRUPT_HMI
         bne     27f
         bl      kvmppc_realmode_hmi_handler
         nop
         cmpdi   r3, 0
-        li      r12, BOOK3S_INTERRUPT_HMI
         /*
          * At this point kvmppc_realmode_hmi_handler may have resync-ed
          * the TB, and if it has, we must not subtract the guest timebase
@@ -2008,10 +2009,8 @@ BEGIN_FTR_SECTION
         lwz     r8, KVM_SPLIT_DO_RESTORE(r3)
         cmpwi   r8, 0
         beq     47f
-        stw     r12, STACK_SLOT_TRAP(r1)
         bl      kvmhv_p9_restore_lpcr
         nop
-        lwz     r12, STACK_SLOT_TRAP(r1)
         b       48f
 47:
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
@@ -2049,6 +2048,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX)
         li      r0, KVM_GUEST_MODE_NONE
         stb     r0, HSTATE_IN_GUEST(r13)
 
+        lwz     r12, STACK_SLOT_TRAP(r1)        /* return trap # in r12 */
         ld      r0, SFS+PPC_LR_STKOFF(r1)
         addi    r1, r1, SFS
         mtlr    r0