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Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_rm_mmu.c')
-rw-r--r--arch/powerpc/kvm/book3s_hv_rm_mmu.c63
1 files changed, 34 insertions, 29 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 84dae821b230..a28a6030ec90 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -53,26 +53,6 @@ static void *real_vmalloc_addr(void *x)
return __va(addr);
}
-#define HPTE_V_HVLOCK 0x40UL
-
-static inline long lock_hpte(unsigned long *hpte, unsigned long bits)
-{
- unsigned long tmp, old;
-
- asm volatile(" ldarx %0,0,%2\n"
- " and. %1,%0,%3\n"
- " bne 2f\n"
- " ori %0,%0,%4\n"
- " stdcx. %0,0,%2\n"
- " beq+ 2f\n"
- " li %1,%3\n"
- "2: isync"
- : "=&r" (tmp), "=&r" (old)
- : "r" (hpte), "r" (bits), "i" (HPTE_V_HVLOCK)
- : "cc", "memory");
- return old == 0;
-}
-
long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel)
{
@@ -126,24 +106,49 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
pteh &= ~0x60UL;
ptel &= ~(HPTE_R_PP0 - kvm->arch.ram_psize);
ptel |= pa;
+
if (pte_index >= HPT_NPTE)
return H_PARAMETER;
if (likely((flags & H_EXACT) == 0)) {
pte_index &= ~7UL;
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
- for (i = 0; ; ++i) {
- if (i == 8)
- return H_PTEG_FULL;
+ for (i = 0; i < 8; ++i) {
if ((*hpte & HPTE_V_VALID) == 0 &&
- lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID))
+ try_lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID))
break;
hpte += 2;
}
+ if (i == 8) {
+ /*
+ * Since try_lock_hpte doesn't retry (not even stdcx.
+ * failures), it could be that there is a free slot
+ * but we transiently failed to lock it. Try again,
+ * actually locking each slot and checking it.
+ */
+ hpte -= 16;
+ for (i = 0; i < 8; ++i) {
+ while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
+ cpu_relax();
+ if ((*hpte & HPTE_V_VALID) == 0)
+ break;
+ *hpte &= ~HPTE_V_HVLOCK;
+ hpte += 2;
+ }
+ if (i == 8)
+ return H_PTEG_FULL;
+ }
pte_index += i;
} else {
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
- if (!lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID))
- return H_PTEG_FULL;
+ if (!try_lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID)) {
+ /* Lock the slot and check again */
+ while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
+ cpu_relax();
+ if (*hpte & HPTE_V_VALID) {
+ *hpte &= ~HPTE_V_HVLOCK;
+ return H_PTEG_FULL;
+ }
+ }
}
/* Save away the guest's idea of the second HPTE dword */
@@ -189,7 +194,7 @@ long kvmppc_h_remove(struct kvm_vcpu *vcpu, unsigned long flags,
if (pte_index >= HPT_NPTE)
return H_PARAMETER;
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
- while (!lock_hpte(hpte, HPTE_V_HVLOCK))
+ while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
cpu_relax();
if ((hpte[0] & HPTE_V_VALID) == 0 ||
((flags & H_AVPN) && (hpte[0] & ~0x7fUL) != avpn) ||
@@ -248,7 +253,7 @@ long kvmppc_h_bulk_remove(struct kvm_vcpu *vcpu)
break;
}
hp = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
- while (!lock_hpte(hp, HPTE_V_HVLOCK))
+ while (!try_lock_hpte(hp, HPTE_V_HVLOCK))
cpu_relax();
found = 0;
if (hp[0] & HPTE_V_VALID) {
@@ -310,7 +315,7 @@ long kvmppc_h_protect(struct kvm_vcpu *vcpu, unsigned long flags,
if (pte_index >= HPT_NPTE)
return H_PARAMETER;
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
- while (!lock_hpte(hpte, HPTE_V_HVLOCK))
+ while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
cpu_relax();
if ((hpte[0] & HPTE_V_VALID) == 0 ||
((flags & H_AVPN) && (hpte[0] & ~0x7fUL) != avpn)) {

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