KVM: PPC: e500: don't use MAS0 as intermediate storage.

This avoids races.  It also means that we use the shadow TLB way,
rather than the hardware hint -- if this is a problem, we could do
a tlbsx before inserting a TLB0 entry.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index e0ab2160932a1b3cc7de031adfc9512dd95c1a2e..f1b37e0de86cd041f58979e4986183a30d7040ca 100644 (file)
--- a/arch/powerpc/kvm/e500_tlb.c
+++ b/arch/powerpc/kvm/e500_tlb.c
@@ -112,13 +112,18 @@ static inline u32 e500_shadow_mas2_attrib(u32 mas2, int usermode)
 /*
  * writing shadow tlb entry to host TLB
  */
-static inline void __write_host_tlbe(struct tlbe *stlbe)
+static inline void __write_host_tlbe(struct tlbe *stlbe, uint32_t mas0)
 {
+       unsigned long flags;
+
+       local_irq_save(flags);
+       mtspr(SPRN_MAS0, mas0);
        mtspr(SPRN_MAS1, stlbe->mas1);
        mtspr(SPRN_MAS2, stlbe->mas2);
        mtspr(SPRN_MAS3, stlbe->mas3);
        mtspr(SPRN_MAS7, stlbe->mas7);
-       __asm__ __volatile__ ("tlbwe\n" : : );
+       asm volatile("isync; tlbwe" : : : "memory");
+       local_irq_restore(flags);
 }
 
 static inline void write_host_tlbe(struct kvmppc_vcpu_e500 *vcpu_e500,
@@ -126,20 +131,15 @@ static inline void write_host_tlbe(struct kvmppc_vcpu_e500 *vcpu_e500,
 {
        struct tlbe *stlbe = &vcpu_e500->shadow_tlb[tlbsel][esel];
 
-       local_irq_disable();
        if (tlbsel == 0) {
-               __write_host_tlbe(stlbe);
+               __write_host_tlbe(stlbe,
+                                 MAS0_TLBSEL(0) |
+                                 MAS0_ESEL(esel & (KVM_E500_TLB0_WAY_NUM - 1)));
        } else {
-               unsigned register mas0;
-
-               mas0 = mfspr(SPRN_MAS0);
-
-               mtspr(SPRN_MAS0, MAS0_TLBSEL(1) | MAS0_ESEL(to_htlb1_esel(esel)));
-               __write_host_tlbe(stlbe);
-
-               mtspr(SPRN_MAS0, mas0);
+               __write_host_tlbe(stlbe,
+                                 MAS0_TLBSEL(1) |
+                                 MAS0_ESEL(to_htlb1_esel(esel)));
        }
-       local_irq_enable();
 }
 
 void kvmppc_e500_tlb_load(struct kvm_vcpu *vcpu, int cpu)