KVM: PPC: Book3S HV: Add helpers for lock/unlock hpte

This adds helper routines for locking and unlocking HPTEs, and uses
them in the rest of the code.  We don't change any locking rules in
this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/kvm_book3s_64.h

@@ -85,6 +85,20 @@ static inline long try_lock_hpte(__be64 *hpte, unsigned long bits)
 	return old == 0;
 }
 
+static inline void unlock_hpte(__be64 *hpte, unsigned long hpte_v)
+{
+	hpte_v &= ~HPTE_V_HVLOCK;
+	asm volatile(PPC_RELEASE_BARRIER "" : : : "memory");
+	hpte[0] = cpu_to_be64(hpte_v);
+}
+
+/* Without barrier */
+static inline void __unlock_hpte(__be64 *hpte, unsigned long hpte_v)
+{
+	hpte_v &= ~HPTE_V_HVLOCK;
+	hpte[0] = cpu_to_be64(hpte_v);
+}
+
 static inline int __hpte_actual_psize(unsigned int lp, int psize)
 {
 	int i, shift;

arch/powerpc/kvm/book3s_64_mmu_hv.c

@@ -338,9 +338,7 @@ static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 	v = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
 	gr = kvm->arch.revmap[index].guest_rpte;
 
-	/* Unlock the HPTE */
+	unlock_hpte(hptep, v);
-	asm volatile("lwsync" : : : "memory");
-	hptep[0] = cpu_to_be64(v);
 	preempt_enable();
 
 	gpte->eaddr = eaddr;
@@ -469,8 +467,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	hpte[0] = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
 	hpte[1] = be64_to_cpu(hptep[1]);
 	hpte[2] = r = rev->guest_rpte;
-	asm volatile("lwsync" : : : "memory");
+	unlock_hpte(hptep, hpte[0]);
-	hptep[0] = cpu_to_be64(hpte[0]);
 	preempt_enable();
 
 	if (hpte[0] != vcpu->arch.pgfault_hpte[0] ||
@@ -621,7 +618,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 
 	hptep[1] = cpu_to_be64(r);
 	eieio();
-	hptep[0] = cpu_to_be64(hpte[0]);
+	__unlock_hpte(hptep, hpte[0]);
 	asm volatile("ptesync" : : : "memory");
 	preempt_enable();
 	if (page && hpte_is_writable(r))
@@ -642,7 +639,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	return ret;
 
  out_unlock:
-	hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
+	__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
 	preempt_enable();
 	goto out_put;
 }
@@ -771,7 +768,7 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			}
 		}
 		unlock_rmap(rmapp);
-		hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
+		__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
 	}
 	return 0;
 }
@@ -857,7 +854,7 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			}
 			ret = 1;
 		}
-		hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
+		__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
 	} while ((i = j) != head);
 
 	unlock_rmap(rmapp);
@@ -974,8 +971,7 @@ static int kvm_test_clear_dirty_npages(struct kvm *kvm, unsigned long *rmapp)
 
 		/* Now check and modify the HPTE */
 		if (!(hptep[0] & cpu_to_be64(HPTE_V_VALID))) {
-			/* unlock and continue */
+			__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
-			hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
 			continue;
 		}
 
@@ -996,9 +992,9 @@ static int kvm_test_clear_dirty_npages(struct kvm *kvm, unsigned long *rmapp)
 				npages_dirty = n;
 			eieio();
 		}
-		v &= ~(HPTE_V_ABSENT | HPTE_V_HVLOCK);
+		v &= ~HPTE_V_ABSENT;
 		v |= HPTE_V_VALID;
-		hptep[0] = cpu_to_be64(v);
+		__unlock_hpte(hptep, v);
 	} while ((i = j) != head);
 
 	unlock_rmap(rmapp);
@@ -1218,8 +1214,7 @@ static long record_hpte(unsigned long flags, __be64 *hptp,
 			r &= ~HPTE_GR_MODIFIED;
 			revp->guest_rpte = r;
 		}
-		asm volatile(PPC_RELEASE_BARRIER "" : : : "memory");
+		unlock_hpte(hptp, be64_to_cpu(hptp[0]));
-		hptp[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
 		preempt_enable();
 		if (!(valid == want_valid && (first_pass || dirty)))
 			ok = 0;

arch/powerpc/kvm/book3s_hv_rm_mmu.c

@@ -150,12 +150,6 @@ static pte_t lookup_linux_pte_and_update(pgd_t *pgdir, unsigned long hva,
 	return kvmppc_read_update_linux_pte(ptep, writing, hugepage_shift);
 }
 
-static inline void unlock_hpte(__be64 *hpte, unsigned long hpte_v)
-{
-	asm volatile(PPC_RELEASE_BARRIER "" : : : "memory");
-	hpte[0] = cpu_to_be64(hpte_v);
-}
-
 long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 		       long pte_index, unsigned long pteh, unsigned long ptel,
 		       pgd_t *pgdir, bool realmode, unsigned long *pte_idx_ret)
@@ -271,10 +265,10 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 				u64 pte;
 				while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
 					cpu_relax();
-				pte = be64_to_cpu(*hpte);
+				pte = be64_to_cpu(hpte[0]);
 				if (!(pte & (HPTE_V_VALID | HPTE_V_ABSENT)))
 					break;
-				*hpte &= ~cpu_to_be64(HPTE_V_HVLOCK);
+				__unlock_hpte(hpte, pte);
 				hpte += 2;
 			}
 			if (i == 8)
@@ -290,9 +284,9 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 
 			while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
 				cpu_relax();
-			pte = be64_to_cpu(*hpte);
+			pte = be64_to_cpu(hpte[0]);
 			if (pte & (HPTE_V_VALID | HPTE_V_ABSENT)) {
-				*hpte &= ~cpu_to_be64(HPTE_V_HVLOCK);
+				__unlock_hpte(hpte, pte);
 				return H_PTEG_FULL;
 			}
 		}
@@ -331,7 +325,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 
 	/* Write the first HPTE dword, unlocking the HPTE and making it valid */
 	eieio();
-	hpte[0] = cpu_to_be64(pteh);
+	__unlock_hpte(hpte, pteh);
 	asm volatile("ptesync" : : : "memory");
 
 	*pte_idx_ret = pte_index;
@@ -412,7 +406,7 @@ long kvmppc_do_h_remove(struct kvm *kvm, unsigned long flags,
 	if ((pte & (HPTE_V_ABSENT | HPTE_V_VALID)) == 0 ||
 	    ((flags & H_AVPN) && (pte & ~0x7fUL) != avpn) ||
 	    ((flags & H_ANDCOND) && (pte & avpn) != 0)) {
-		hpte[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
+		__unlock_hpte(hpte, pte);
 		return H_NOT_FOUND;
 	}
 
@@ -548,7 +542,7 @@ long kvmppc_h_bulk_remove(struct kvm_vcpu *vcpu)
 				be64_to_cpu(hp[0]), be64_to_cpu(hp[1]));
 			rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
 			args[j] |= rcbits << (56 - 5);
-			hp[0] = 0;
+			__unlock_hpte(hp, 0);
 		}
 	}
 
@@ -574,7 +568,7 @@ long kvmppc_h_protect(struct kvm_vcpu *vcpu, unsigned long flags,
 	pte = be64_to_cpu(hpte[0]);
 	if ((pte & (HPTE_V_ABSENT | HPTE_V_VALID)) == 0 ||
 	    ((flags & H_AVPN) && (pte & ~0x7fUL) != avpn)) {
-		hpte[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
+		__unlock_hpte(hpte, pte);
 		return H_NOT_FOUND;
 	}
 
@@ -755,8 +749,7 @@ long kvmppc_hv_find_lock_hpte(struct kvm *kvm, gva_t eaddr, unsigned long slb_v,
 				/* Return with the HPTE still locked */
 				return (hash << 3) + (i >> 1);
 
-			/* Unlock and move on */
+			__unlock_hpte(&hpte[i], v);
-			hpte[i] = cpu_to_be64(v);
 		}
 
 		if (val & HPTE_V_SECONDARY)