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Commit dd9e5b7b authored by Alexander Yarygin's avatar Alexander Yarygin Committed by Christian Borntraeger
Browse files

KVM: s390: Fix low-address protection for real addresses 



The kvm_s390_check_low_addr_protection() function is used only with real
addresses. According to the POP (the "Low-Address Protection"
paragraph in chapter 3), if the effective address is real or absolute,
the low-address protection procedure should raise a PROTECTION exception
only when the low-address protection is enabled in the control register
0 and the address is low.
This patch removes ASCE checks from the function and renames it to
better reflect its behavior.

Cc: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: default avatarAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 40f5b735

arch/s390/kvm/gaccess.c

+6 −5
Original line number Diff line number Diff line
@@ -697,28 +697,29 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, 
}



/**

 * kvm_s390_check_low_addr_protection - check for low-address protection

 * @ga: Guest address

 * kvm_s390_check_low_addr_prot_real - check for low-address protection

 * @gra: Guest real address

 *

 * Checks whether an address is subject to low-address protection and set

 * up vcpu->arch.pgm accordingly if necessary.

 *

 * Return: 0 if no protection exception, or PGM_PROTECTION if protected.

 */

int kvm_s390_check_low_addr_protection(struct kvm_vcpu *vcpu, unsigned long ga)

int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)

{

	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;

	psw_t *psw = &vcpu->arch.sie_block->gpsw;

	struct trans_exc_code_bits *tec_bits;

	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};



	if (!is_low_address(ga) || !low_address_protection_enabled(vcpu))

	if (!ctlreg0.lap || !is_low_address(gra))

		return 0;



	memset(pgm, 0, sizeof(*pgm));

	tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;

	tec_bits->fsi = FSI_STORE;

	tec_bits->as = psw_bits(*psw).as;

	tec_bits->addr = ga >> PAGE_SHIFT;

	tec_bits->addr = gra >> PAGE_SHIFT;

	pgm->code = PGM_PROTECTION;



	return pgm->code;

arch/s390/kvm/gaccess.h

+1 −1
Original line number Diff line number Diff line
@@ -330,6 +330,6 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 
void ipte_lock(struct kvm_vcpu *vcpu);

void ipte_unlock(struct kvm_vcpu *vcpu);

int ipte_lock_held(struct kvm_vcpu *vcpu);

int kvm_s390_check_low_addr_protection(struct kvm_vcpu *vcpu, unsigned long ga);

int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);



#endif /* __KVM_S390_GACCESS_H */

arch/s390/kvm/priv.c

+2 −2
Original line number Diff line number Diff line
@@ -207,7 +207,7 @@ static int handle_test_block(struct kvm_vcpu *vcpu) 
	kvm_s390_get_regs_rre(vcpu, NULL, &reg2);

	addr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;

	addr = kvm_s390_logical_to_effective(vcpu, addr);

	if (kvm_s390_check_low_addr_protection(vcpu, addr))

	if (kvm_s390_check_low_addr_prot_real(vcpu, addr))

		return kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm);

	addr = kvm_s390_real_to_abs(vcpu, addr);
@@ -680,7 +680,7 @@ static int handle_pfmf(struct kvm_vcpu *vcpu) 
	}



	if (vcpu->run->s.regs.gprs[reg1] & PFMF_CF) {

		if (kvm_s390_check_low_addr_protection(vcpu, start))

		if (kvm_s390_check_low_addr_prot_real(vcpu, start))

			return kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm);

	}