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Commit 9fbc0276 authored by Thomas Huth's avatar Thomas Huth Committed by Christian Borntraeger
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KVM: s390: Add a generic function for translating guest addresses 



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: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 1f854112

arch/s390/kvm/gaccess.c

+53 −0
Original line number Diff line number Diff line
@@ -644,6 +644,59 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, 
	return rc;

}



/**

 * 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

arch/s390/kvm/gaccess.h

+3 −0
Original line number Diff line number Diff line
@@ -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);