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From:   Pierre Morel <pmorel@linux.ibm.com>
To:     kvm@vger.kernel.org
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        borntraeger@de.ibm.com, frankja@linux.ibm.com, cohuck@redhat.com,
        david@redhat.com, thuth@redhat.com, imbrenda@linux.ibm.com,
        hca@linux.ibm.com, gor@linux.ibm.com, pmorel@linux.ibm.com,
        wintera@linux.ibm.com, seiden@linux.ibm.com, nrb@linux.ibm.com
Subject: [PATCH v10 1/3] KVM: s390: ipte lock for SCA access should be contained in KVM
Date:   Mon, 20 Jun 2022 14:54:35 +0200
Message-Id: <20220620125437.37122-2-pmorel@linux.ibm.com>
In-Reply-To: <20220620125437.37122-1-pmorel@linux.ibm.com>
References: <20220620125437.37122-1-pmorel@linux.ibm.com>
MIME-Version: 1.0
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We can check if SIIF is enabled by testing the sclp_info struct
instead of testing the sie control block eca variable.
sclp.has_ssif is the only requirement to set ECA_SII anyway
so we can go straight to the source for that.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
 arch/s390/kvm/gaccess.c | 96 ++++++++++++++++++++---------------------
 arch/s390/kvm/gaccess.h |  6 +--
 arch/s390/kvm/priv.c    |  6 +--
 3 files changed, 54 insertions(+), 54 deletions(-)

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 227ed0009354..082ec5f2c3a5 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -262,77 +262,77 @@ struct aste {
 	/* .. more fields there */
 };
 
-int ipte_lock_held(struct kvm_vcpu *vcpu)
+int ipte_lock_held(struct kvm *kvm)
 {
-	if (vcpu->arch.sie_block->eca & ECA_SII) {
+	if (sclp.has_siif) {
 		int rc;
 
-		read_lock(&vcpu->kvm->arch.sca_lock);
-		rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0;
-		read_unlock(&vcpu->kvm->arch.sca_lock);
+		read_lock(&kvm->arch.sca_lock);
+		rc = kvm_s390_get_ipte_control(kvm)->kh != 0;
+		read_unlock(&kvm->arch.sca_lock);
 		return rc;
 	}
-	return vcpu->kvm->arch.ipte_lock_count != 0;
+	return kvm->arch.ipte_lock_count != 0;
 }
 
-static void ipte_lock_simple(struct kvm_vcpu *vcpu)
+static void ipte_lock_simple(struct kvm *kvm)
 {
 	union ipte_control old, new, *ic;
 
-	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
-	vcpu->kvm->arch.ipte_lock_count++;
-	if (vcpu->kvm->arch.ipte_lock_count > 1)
+	mutex_lock(&kvm->arch.ipte_mutex);
+	kvm->arch.ipte_lock_count++;
+	if (kvm->arch.ipte_lock_count > 1)
 		goto out;
 retry:
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
 	do {
 		old = READ_ONCE(*ic);
 		if (old.k) {
-			read_unlock(&vcpu->kvm->arch.sca_lock);
+			read_unlock(&kvm->arch.sca_lock);
 			cond_resched();
 			goto retry;
 		}
 		new = old;
 		new.k = 1;
 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
-	read_unlock(&vcpu->kvm->arch.sca_lock);
+	read_unlock(&kvm->arch.sca_lock);
 out:
-	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+	mutex_unlock(&kvm->arch.ipte_mutex);
 }
 
-static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
+static void ipte_unlock_simple(struct kvm *kvm)
 {
 	union ipte_control old, new, *ic;
 
-	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
-	vcpu->kvm->arch.ipte_lock_count--;
-	if (vcpu->kvm->arch.ipte_lock_count)
+	mutex_lock(&kvm->arch.ipte_mutex);
+	kvm->arch.ipte_lock_count--;
+	if (kvm->arch.ipte_lock_count)
 		goto out;
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
 	do {
 		old = READ_ONCE(*ic);
 		new = old;
 		new.k = 0;
 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
-	read_unlock(&vcpu->kvm->arch.sca_lock);
-	wake_up(&vcpu->kvm->arch.ipte_wq);
+	read_unlock(&kvm->arch.sca_lock);
+	wake_up(&kvm->arch.ipte_wq);
 out:
-	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
+	mutex_unlock(&kvm->arch.ipte_mutex);
 }
 
-static void ipte_lock_siif(struct kvm_vcpu *vcpu)
+static void ipte_lock_siif(struct kvm *kvm)
 {
 	union ipte_control old, new, *ic;
 
 retry:
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
 	do {
 		old = READ_ONCE(*ic);
 		if (old.kg) {
-			read_unlock(&vcpu->kvm->arch.sca_lock);
+			read_unlock(&kvm->arch.sca_lock);
 			cond_resched();
 			goto retry;
 		}
@@ -340,15 +340,15 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu)
 		new.k = 1;
 		new.kh++;
 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
-	read_unlock(&vcpu->kvm->arch.sca_lock);
+	read_unlock(&kvm->arch.sca_lock);
 }
 
-static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
+static void ipte_unlock_siif(struct kvm *kvm)
 {
 	union ipte_control old, new, *ic;
 
-	read_lock(&vcpu->kvm->arch.sca_lock);
-	ic = kvm_s390_get_ipte_control(vcpu->kvm);
+	read_lock(&kvm->arch.sca_lock);
+	ic = kvm_s390_get_ipte_control(kvm);
 	do {
 		old = READ_ONCE(*ic);
 		new = old;
@@ -356,25 +356,25 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
 		if (!new.kh)
 			new.k = 0;
 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
-	read_unlock(&vcpu->kvm->arch.sca_lock);
+	read_unlock(&kvm->arch.sca_lock);
 	if (!new.kh)
-		wake_up(&vcpu->kvm->arch.ipte_wq);
+		wake_up(&kvm->arch.ipte_wq);
 }
 
-void ipte_lock(struct kvm_vcpu *vcpu)
+void ipte_lock(struct kvm *kvm)
 {
-	if (vcpu->arch.sie_block->eca & ECA_SII)
-		ipte_lock_siif(vcpu);
+	if (sclp.has_siif)
+		ipte_lock_siif(kvm);
 	else
-		ipte_lock_simple(vcpu);
+		ipte_lock_simple(kvm);
 }
 
-void ipte_unlock(struct kvm_vcpu *vcpu)
+void ipte_unlock(struct kvm *kvm)
 {
-	if (vcpu->arch.sie_block->eca & ECA_SII)
-		ipte_unlock_siif(vcpu);
+	if (sclp.has_siif)
+		ipte_unlock_siif(kvm);
 	else
-		ipte_unlock_simple(vcpu);
+		ipte_unlock_simple(kvm);
 }
 
 static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
@@ -1086,7 +1086,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
 	try_storage_prot_override = storage_prot_override_applicable(vcpu);
 	need_ipte_lock = psw_bits(*psw).dat && !asce.r;
 	if (need_ipte_lock)
-		ipte_lock(vcpu);
+		ipte_lock(vcpu->kvm);
 	/*
 	 * Since we do the access further down ultimately via a move instruction
 	 * that does key checking and returns an error in case of a protection
@@ -1127,7 +1127,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
 	}
 out_unlock:
 	if (need_ipte_lock)
-		ipte_unlock(vcpu);
+		ipte_unlock(vcpu->kvm);
 	if (nr_pages > ARRAY_SIZE(gpa_array))
 		vfree(gpas);
 	return rc;
@@ -1199,10 +1199,10 @@ int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
 	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
 	if (rc)
 		return rc;
-	ipte_lock(vcpu);
+	ipte_lock(vcpu->kvm);
 	rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode,
 				 access_key);
-	ipte_unlock(vcpu);
+	ipte_unlock(vcpu->kvm);
 
 	return rc;
 }
@@ -1465,7 +1465,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
 	 * tables/pointers we read stay valid - unshadowing is however
 	 * always possible - only guest_table_lock protects us.
 	 */
-	ipte_lock(vcpu);
+	ipte_lock(vcpu->kvm);
 
 	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
 	if (rc)
@@ -1499,7 +1499,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
 	pte.p |= dat_protection;
 	if (!rc)
 		rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
-	ipte_unlock(vcpu);
+	ipte_unlock(vcpu->kvm);
 	mmap_read_unlock(sg->mm);
 	return rc;
 }
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 1124ff282012..9408d6cc8e2c 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -440,9 +440,9 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 	return access_guest_real(vcpu, gra, data, len, 0);
 }
 
-void ipte_lock(struct kvm_vcpu *vcpu);
-void ipte_unlock(struct kvm_vcpu *vcpu);
-int ipte_lock_held(struct kvm_vcpu *vcpu);
+void ipte_lock(struct kvm *kvm);
+void ipte_unlock(struct kvm *kvm);
+int ipte_lock_held(struct kvm *kvm);
 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
 
 /* MVPG PEI indication bits */
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 83bb5cf97282..12c464c7cddf 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -442,7 +442,7 @@ static int handle_ipte_interlock(struct kvm_vcpu *vcpu)
 	vcpu->stat.instruction_ipte_interlock++;
 	if (psw_bits(vcpu->arch.sie_block->gpsw).pstate)
 		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
-	wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu));
+	wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu->kvm));
 	kvm_s390_retry_instr(vcpu);
 	VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation");
 	return 0;
@@ -1471,7 +1471,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
 	access_key = (operand2 & 0xf0) >> 4;
 
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
-		ipte_lock(vcpu);
+		ipte_lock(vcpu->kvm);
 
 	ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,
 					       GACC_STORE, access_key);
@@ -1508,7 +1508,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu)
 	}
 
 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
-		ipte_unlock(vcpu);
+		ipte_unlock(vcpu->kvm);
 	return ret;
 }
 
-- 
2.31.1