[PATCH v2 01/20] KVM: s390: vsie: Add SCAO read and write helpers

[Christoph Schlameuss <schlameuss@linux.ibm.com>]

Introduce some small helper functions to get and set the system control
area origin address from the SIE control block.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
---
 arch/s390/kvm/vsie.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index eb60a359d0aa..010327a6ebee 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -71,6 +71,22 @@ static_assert(sizeof(struct vsie_page) == PAGE_SIZE);
 static_assert(offsetof(struct vsie_page, mcck_info) == offsetof(struct sie_page, mcck_info));
 static_assert(IS_ALIGNED(offsetof(struct vsie_page, crycb), 8));
 
+static unsigned long read_scao(struct kvm *kvm, struct kvm_s390_sie_block *scb)
+{
+	unsigned long vsie_sca = READ_ONCE(scb->scaol) & ~0xfUL;
+
+	if (test_kvm_cpu_feat(kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
+		vsie_sca |= (u64)READ_ONCE(scb->scaoh) << 32;
+
+	return vsie_sca;
+}
+
+static void write_scao(struct kvm_s390_sie_block *scb, unsigned long hpa)
+{
+	scb->scaoh = (u32)((u64)hpa >> 32);
+	scb->scaol = (u32)(u64)hpa;
+}
+
 /* trigger a validity icpt for the given scb */
 static int set_validity_icpt(struct kvm_s390_sie_block *scb,
 			     __u16 reason_code)
@@ -715,8 +731,7 @@ static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	if (hpa) {
 		unpin_guest_page(vcpu->kvm, vsie_page->sca_gpa, hpa);
 		vsie_page->sca_gpa = 0;
-		scb_s->scaol = 0;
-		scb_s->scaoh = 0;
+		write_scao(scb_s, 0);
 	}
 
 	hpa = scb_s->itdba;
@@ -770,9 +785,7 @@ static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	gpa_t gpa;
 	int rc = 0;
 
-	gpa = READ_ONCE(scb_o->scaol) & ~0xfUL;
-	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
-		gpa |= (u64) READ_ONCE(scb_o->scaoh) << 32;
+	gpa = read_scao(vcpu->kvm, scb_o);
 	if (gpa) {
 		if (gpa < 2 * PAGE_SIZE)
 			rc = set_validity_icpt(scb_s, 0x0038U);
@@ -789,8 +802,7 @@ static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 		if (rc)
 			goto unpin;
 		vsie_page->sca_gpa = gpa;
-		scb_s->scaoh = (u32)((u64)hpa >> 32);
-		scb_s->scaol = (u32)(u64)hpa;
+		write_scao(scb_s, hpa);
 	}
 
 	gpa = READ_ONCE(scb_o->itdba) & ~0xffUL;

-- 
2.55.0