KVM: s390: gaccess: Cleanup access to guest pages

[ Upstream commit bad13799e0305deb258372b7298a86be4c78aaba ]

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>
Stable-dep-of: e8061f06185b ("KVM: s390: gaccess: Check if guest address is in memslot")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 9b9bfc333e62d08f2da1deefb62dddd30ce91e48..164f96ba61dd216dd8451ecd22a4e1721676ab1a 100644 (file)
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -866,6 +866,20 @@ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
        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, unsigned long ga, u8 ar, void *data,
        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 *vcpu, unsigned long gra,
        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;