KVM: s390: gaccess: Refactor gpa and length calculation

Improve readability by renaming the length variable and
not calculating the offset manually.

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: <20211126164549.7046-2-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 6af59c5..45966fb 100644 (file)
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -831,8 +831,9 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
                 unsigned long len, enum gacc_mode mode)
 {
        psw_t *psw = &vcpu->arch.sie_block->gpsw;
-       unsigned long _len, nr_pages, gpa, idx;
+       unsigned long nr_pages, gpa, idx;
        unsigned long pages_array[2];
+       unsigned int fragment_len;
        unsigned long *pages;
        int need_ipte_lock;
        union asce asce;
@@ -855,15 +856,15 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
                ipte_lock(vcpu);
        rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode);
        for (idx = 0; idx < nr_pages && !rc; idx++) {
-               gpa = *(pages + idx) + (ga & ~PAGE_MASK);
-               _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
+               gpa = pages[idx] + offset_in_page(ga);
+               fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);
                if (mode == GACC_STORE)
-                       rc = kvm_write_guest(vcpu->kvm, gpa, data, _len);
+                       rc = kvm_write_guest(vcpu->kvm, gpa, data, fragment_len);
                else
-                       rc = kvm_read_guest(vcpu->kvm, gpa, data, _len);
-               len -= _len;
-               ga += _len;
-               data += _len;
+                       rc = kvm_read_guest(vcpu->kvm, gpa, data, fragment_len);
+               len -= fragment_len;
+               ga += fragment_len;
+               data += fragment_len;
        }
        if (need_ipte_lock)
                ipte_unlock(vcpu);
@@ -875,19 +876,20 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
                      void *data, unsigned long len, enum gacc_mode mode)
 {
-       unsigned long _len, gpa;
+       unsigned int fragment_len;
+       unsigned long gpa;
        int rc = 0;
 
        while (len && !rc) {
                gpa = kvm_s390_real_to_abs(vcpu, gra);
-               _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
+               fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);
                if (mode)
-                       rc = write_guest_abs(vcpu, gpa, data, _len);
+                       rc = write_guest_abs(vcpu, gpa, data, fragment_len);
                else
-                       rc = read_guest_abs(vcpu, gpa, data, _len);
-               len -= _len;
-               gra += _len;
-               data += _len;
+                       rc = read_guest_abs(vcpu, gpa, data, fragment_len);
+               len -= fragment_len;
+               gra += fragment_len;
+               data += fragment_len;
        }
        return rc;
 }