From: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
This patch adds a function for translating logical guest addresses into
physical guest addresses without touching the memory at the given location.
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
arch/s390/kvm/gaccess.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++
arch/s390/kvm/gaccess.h | 3 +++
2 files changed, 56 insertions(+)
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index db608c3..5f73826 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -645,6 +645,59 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
}
/**
+ * guest_translate_address - translate guest logical into guest absolute address
+ *
+ * Parameter semantics are the same as the ones from guest_translate.
+ * The memory contents at the guest address are not changed.
+ *
+ * Note: The IPTE lock is not taken during this function, so the caller
+ * has to take care of this.
+ */
+int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
+ unsigned long *gpa, int write)
+{
+ struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
+ psw_t *psw = &vcpu->arch.sie_block->gpsw;
+ struct trans_exc_code_bits *tec;
+ union asce asce;
+ int rc;
+
+ /* Access register mode is not supported yet. */
+ if (psw_bits(*psw).t && psw_bits(*psw).as == PSW_AS_ACCREG)
+ return -EOPNOTSUPP;
+
+ gva = kvm_s390_logical_to_effective(vcpu, gva);
+ memset(pgm, 0, sizeof(*pgm));
+ tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
+ tec->as = psw_bits(*psw).as;
+ tec->fsi = write ? FSI_STORE : FSI_FETCH;
+ tec->addr = gva >> PAGE_SHIFT;
+ if (is_low_address(gva) && low_address_protection_enabled(vcpu)) {
+ if (write) {
+ rc = pgm->code = PGM_PROTECTION;
+ return rc;
+ }
+ }
+
+ asce.val = get_vcpu_asce(vcpu);
+ if (psw_bits(*psw).t && !asce.r) { /* Use DAT? */
+ rc = guest_translate(vcpu, gva, gpa, write);
+ if (rc > 0) {
+ if (rc == PGM_PROTECTION)
+ tec->b61 = 1;
+ pgm->code = rc;
+ }
+ } else {
+ rc = 0;
+ *gpa = kvm_s390_real_to_abs(vcpu, gva);
+ if (kvm_is_error_gpa(vcpu->kvm, *gpa))
+ rc = pgm->code = PGM_ADDRESSING;
+ }
+
+ return rc;
+}
+
+/**
* kvm_s390_check_low_addr_protection - check for low-address protection
* @ga: Guest address
*
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index a07ee08..2d37a46 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -155,6 +155,9 @@ int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
return kvm_read_guest(vcpu->kvm, gpa, data, len);
}
+int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
+ unsigned long *gpa, int write);
+
int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
unsigned long len, int write);
--
1.8.4.2
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