2 files changed, 27 insertions, 6 deletions

diff --git a/arch/powerpc/include/asm/kvm_asm.h b/arch/powerpc/include/asm/kvm_asm.h
index e2d4d467ee93..1bd92fd43cfb 100644
--- a/arch/powerpc/include/asm/kvm_asm.h
+++ b/arch/powerpc/include/asm/kvm_asm.h
@@ -138,6 +138,8 @@
 #define KVM_GUEST_MODE_NONE     0
 #define KVM_GUEST_MODE_GUEST    1
 #define KVM_GUEST_MODE_SKIP     2
+#define KVM_GUEST_MODE_GUEST_HV 3
+#define KVM_GUEST_MODE_HOST_HV  4
 
 #define KVM_INST_FETCH_FAILED   -1
 
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 6e3370f42a63..84105eb18a0e 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -387,6 +387,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
         mtspr   SPRN_DAR, r5
         mtspr   SPRN_DSISR, r6
 
+        li      r6, KVM_GUEST_MODE_HOST_HV
+        stb     r6, HSTATE_IN_GUEST(r13)
+
 BEGIN_FTR_SECTION
         /* Restore AMR and UAMOR, set AMOR to all 1s */
         ld      r5,VCPU_AMR(r4)
@@ -690,7 +693,7 @@ fast_guest_return:
         mtspr   SPRN_HSRR1,r11
 
         /* Activate guest mode, so faults get handled by KVM */
-        li      r9, KVM_GUEST_MODE_GUEST
+        li      r9, KVM_GUEST_MODE_GUEST_HV
         stb     r9, HSTATE_IN_GUEST(r13)
 
         /* Enter guest */
@@ -750,6 +753,14 @@ kvmppc_interrupt:
          */
         /* abuse host_r2 as third scratch area; we get r2 from PACATOC(r13) */
         std     r9, HSTATE_HOST_R2(r13)
+
+        lbz     r9, HSTATE_IN_GUEST(r13)
+        cmpwi   r9, KVM_GUEST_MODE_HOST_HV
+        beq     kvmppc_bad_host_intr
+        /* We're now back in the host but in guest MMU context */
+        li      r9, KVM_GUEST_MODE_HOST_HV
+        stb     r9, HSTATE_IN_GUEST(r13)
+
         ld      r9, HSTATE_KVM_VCPU(r13)
 
         /* Save registers */
@@ -801,10 +812,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
         std     r3, VCPU_GPR(R13)(r9)
         std     r4, VCPU_LR(r9)
 
-        /* Unset guest mode */
-        li      r0, KVM_GUEST_MODE_NONE
-        stb     r0, HSTATE_IN_GUEST(r13)
-
         stw     r12,VCPU_TRAP(r9)
 
         /* Save HEIR (HV emulation assist reg) in last_inst
@@ -1198,6 +1205,10 @@ BEGIN_FTR_SECTION
         mtspr   SPRN_AMR,r6
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 
+        /* Unset guest mode */
+        li      r0, KVM_GUEST_MODE_NONE
+        stb     r0, HSTATE_IN_GUEST(r13)
+
         /* Switch DSCR back to host value */
 BEGIN_FTR_SECTION
         mfspr   r8, SPRN_DSCR
@@ -1400,7 +1411,7 @@ fast_interrupt_c_return:
         stw     r8, VCPU_LAST_INST(r9)
 
         /* Unset guest mode. */
-        li      r0, KVM_GUEST_MODE_NONE
+        li      r0, KVM_GUEST_MODE_HOST_HV
         stb     r0, HSTATE_IN_GUEST(r13)
         b       guest_exit_cont
 
@@ -1949,3 +1960,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
         lwz     r7,VCPU_VRSAVE(r4)
         mtspr   SPRN_VRSAVE,r7
         blr
+
+/*
+ * We come here if we get any exception or interrupt while we are
+ * executing host real mode code while in guest MMU context.
+ * For now just spin, but we should do something better.
+ */
+kvmppc_bad_host_intr:
+        b       .