From: Janis Schoetterl-Glausch <scgl@linux.ibm.com>

Date: Fri, 26 Nov 2021 17:45:49 +0100

Subject: KVM: s390: gaccess: Cleanup access to guest pages

Git-commit: bad13799e0305deb258372b7298a86be4c78aaba

Patch-mainline: v5.17-rc1

References: jsc#PED-579

Introduce a helper function for guest frame access.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

Reviewed-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

Message-Id: <20211126164549.7046-4-scgl@linux.ibm.com>

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

Acked-by: Petr Tesarik <ptesarik@suse.com>

---

 arch/s390/kvm/gaccess.c |   24 ++++++++++++++++--------

 1 file changed, 16 insertions(+), 8 deletions(-)

--- a/arch/s390/kvm/gaccess.c

+++ b/arch/s390/kvm/gaccess.c

@@ -866,6 +866,20 @@ static int guest_range_to_gpas(struct kv

 	return 0;

 }

+static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,

+			     void *data, unsigned int len)

+{

+	const unsigned int offset = offset_in_page(gpa);

+	const gfn_t gfn = gpa_to_gfn(gpa);

+	int rc;

+

+	if (mode == GACC_STORE)

+		rc = kvm_write_guest_page(kvm, gfn, data, offset, len);

+	else

+		rc = kvm_read_guest_page(kvm, gfn, data, offset, len);

+	return rc;

+}

+

 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,

 		 unsigned long len, enum gacc_mode mode)

 {

@@ -896,10 +910,7 @@ int access_guest(struct kvm_vcpu *vcpu,

 	rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode);

 	for (idx = 0; idx < nr_pages && !rc; idx++) {

 		fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len);

-		if (mode == GACC_STORE)

-			rc = kvm_write_guest(vcpu->kvm, gpas[idx], data, fragment_len);

-		else

-			rc = kvm_read_guest(vcpu->kvm, gpas[idx], data, fragment_len);

+		rc = access_guest_page(vcpu->kvm, mode, gpas[idx], data, fragment_len);

 		len -= fragment_len;

 		data += fragment_len;

 	}

@@ -920,10 +931,7 @@ int access_guest_real(struct kvm_vcpu *v

 	while (len && !rc) {

 		gpa = kvm_s390_real_to_abs(vcpu, gra);

 		fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);

-		if (mode)

-			rc = write_guest_abs(vcpu, gpa, data, fragment_len);

-		else

-			rc = read_guest_abs(vcpu, gpa, data, fragment_len);

+		rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len);

 		len -= fragment_len;

 		gra += fragment_len;

 		data += fragment_len;