[PATCH v3 3/3] KVM: s390: gaccess: Cleanup access to guest pages

Janis Schoetterl-Glausch
2021-11-26T16:48:07Z

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>
---
arch/s390/kvm/gaccess.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index c09659609d68..9193f0de40b1 100644
--- 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;
--
2.32.0