[PATCH 09/15] KVM: PPC: e500: don't use MAS0 as intermediate storage.

Alexander Graf
2011-06-17T14:49:46Z

From: Scott Wood <scottwood@freescale.com>

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>
---
arch/powerpc/kvm/e500_tlb.c | 26 +++++++++++++-------------
1 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index e0ab216..f1b37e0 100644
--- 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)
--
1.6.0.2