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Commit dc5008b9 authored by Heiko Carstens's avatar Heiko Carstens Committed by Marcelo Tosatti
Browse files

s390/kvm: remove explicit -EFAULT return code checking on guest access 



Let's change to the paradigm that every return code from guest memory
access functions that is not zero translates to -EFAULT and do not
explictly compare.
Explictly comparing the return value with -EFAULT has already shown to
be a bit fragile. In addition this is closer to the handling of
copy_to/from_user functions, which imho is in general a good idea.

Also shorten the return code handling in interrupt.c a bit.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 59a1fa2d

arch/s390/kvm/intercept.c

+2 −2
Original line number Diff line number Diff line
@@ -45,7 +45,7 @@ static int handle_lctlg(struct kvm_vcpu *vcpu) 
	do {

		rc = get_guest_u64(vcpu, useraddr,

				   &vcpu->arch.sie_block->gcr[reg]);

		if (rc == -EFAULT) {

		if (rc) {

			kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

			break;

		}
@@ -79,7 +79,7 @@ static int handle_lctl(struct kvm_vcpu *vcpu) 
	reg = reg1;

	do {

		rc = get_guest_u32(vcpu, useraddr, &val);

		if (rc == -EFAULT) {

		if (rc) {

			kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

			break;

		}

arch/s390/kvm/interrupt.c

+69 −172
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
				   struct kvm_s390_interrupt_info *inti)

{

	const unsigned short table[] = { 2, 4, 4, 6 };

	int rc, exception = 0;

	int rc = 0;



	switch (inti->type) {

	case KVM_S390_INT_EMERGENCY:
@@ -189,48 +189,24 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
		trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,

						 inti->emerg.code, 0);

		rc  = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1201);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->emerg.code);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

		rc |= put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->emerg.code);

		rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_EXT_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;

		break;



	case KVM_S390_INT_EXTERNAL_CALL:

		VCPU_EVENT(vcpu, 4, "%s", "interrupt: sigp ext call");

		vcpu->stat.deliver_external_call++;

		trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,

						 inti->extcall.code, 0);

		rc  = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1202);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->extcall.code);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

		rc |= put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, inti->extcall.code);

		rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_EXT_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;

		break;



	case KVM_S390_INT_SERVICE:

		VCPU_EVENT(vcpu, 4, "interrupt: sclp parm:%x",

			   inti->ext.ext_params);
@@ -238,24 +214,12 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
		trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,

						 inti->ext.ext_params, 0);

		rc  = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2401);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

		rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_EXT_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);

		if (rc == -EFAULT)

			exception = 1;

		rc |= put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);

		break;



	case KVM_S390_INT_VIRTIO:

		VCPU_EVENT(vcpu, 4, "interrupt: virtio parm:%x,parm64:%llx",

			   inti->ext.ext_params, inti->ext.ext_params2);
@@ -264,33 +228,15 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
						 inti->ext.ext_params,

						 inti->ext.ext_params2);

		rc  = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2603);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, 0x0d00);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

		rc |= put_guest_u16(vcpu, __LC_EXT_CPU_ADDR, 0x0d00);

		rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_EXT_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u64(vcpu, __LC_EXT_PARAMS2,

		rc |= put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);

		rc |= put_guest_u64(vcpu, __LC_EXT_PARAMS2,

				    inti->ext.ext_params2);

		if (rc == -EFAULT)

			exception = 1;

		break;



	case KVM_S390_SIGP_STOP:

		VCPU_EVENT(vcpu, 4, "%s", "interrupt: cpu stop");

		vcpu->stat.deliver_stop_signal++;
@@ -313,18 +259,14 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
		vcpu->stat.deliver_restart_signal++;

		trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,

						 0, 0);

		rc = copy_to_guest(vcpu, offsetof(struct _lowcore,

		  restart_old_psw), &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

			offsetof(struct _lowcore, restart_psw), sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;

		rc  = copy_to_guest(vcpu,

				    offsetof(struct _lowcore, restart_old_psw),

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      offsetof(struct _lowcore, restart_psw),

				      sizeof(psw_t));

		atomic_clear_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);

		break;



	case KVM_S390_PROGRAM_INT:

		VCPU_EVENT(vcpu, 4, "interrupt: pgm check code:%x, ilc:%x",

			   inti->pgm.code,
@@ -333,23 +275,12 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
		trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,

						 inti->pgm.code, 0);

		rc  = put_guest_u16(vcpu, __LC_PGM_INT_CODE, inti->pgm.code);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u16(vcpu, __LC_PGM_ILC,

		rc |= put_guest_u16(vcpu, __LC_PGM_ILC,

				    table[vcpu->arch.sie_block->ipa >> 14]);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_PGM_OLD_PSW,

		rc |= copy_to_guest(vcpu, __LC_PGM_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_PGM_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;

		break;



	case KVM_S390_MCHK:
@@ -360,22 +291,11 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
						 inti->mchk.mcic);

		rc  = kvm_s390_vcpu_store_status(vcpu,

						 KVM_S390_STORE_STATUS_PREFIXED);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u64(vcpu, __LC_MCCK_CODE, inti->mchk.mcic);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_MCK_OLD_PSW,

		rc |= put_guest_u64(vcpu, __LC_MCCK_CODE, inti->mchk.mcic);

		rc |= copy_to_guest(vcpu, __LC_MCK_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_MCK_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;

		break;



	case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
@@ -390,39 +310,22 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 
						 param0, param1);

		rc  = put_guest_u16(vcpu, __LC_SUBCHANNEL_ID,

				    inti->io.subchannel_id);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u16(vcpu, __LC_SUBCHANNEL_NR,

		rc |= put_guest_u16(vcpu, __LC_SUBCHANNEL_NR,

				    inti->io.subchannel_nr);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u32(vcpu, __LC_IO_INT_PARM,

		rc |= put_guest_u32(vcpu, __LC_IO_INT_PARM,

				    inti->io.io_int_parm);

		if (rc == -EFAULT)

			exception = 1;



		rc = put_guest_u32(vcpu, __LC_IO_INT_WORD,

		rc |= put_guest_u32(vcpu, __LC_IO_INT_WORD,

				    inti->io.io_int_word);

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_to_guest(vcpu, __LC_IO_OLD_PSW,

		rc |= copy_to_guest(vcpu, __LC_IO_OLD_PSW,

				    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;



		rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

		rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

				      __LC_IO_NEW_PSW, sizeof(psw_t));

		if (rc == -EFAULT)

			exception = 1;

		break;

	}

	default:

		BUG();

	}

	if (exception) {

	if (rc) {

		printk("kvm: The guest lowcore is not mapped during interrupt "

		       "delivery, killing userspace\n");

		do_exit(SIGKILL);
@@ -431,24 +334,18 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, 


static int __try_deliver_ckc_interrupt(struct kvm_vcpu *vcpu)

{

	int rc, exception = 0;

	int rc;



	if (psw_extint_disabled(vcpu))

		return 0;

	if (!(vcpu->arch.sie_block->gcr[0] & 0x800ul))

		return 0;

	rc  = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1004);

	if (rc == -EFAULT)

		exception = 1;

	rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

	rc |= copy_to_guest(vcpu, __LC_EXT_OLD_PSW,

			    &vcpu->arch.sie_block->gpsw, sizeof(psw_t));

	if (rc == -EFAULT)

		exception = 1;

	rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

	rc |= copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,

			      __LC_EXT_NEW_PSW, sizeof(psw_t));

	if (rc == -EFAULT)

		exception = 1;

	if (exception) {

	if (rc) {

		printk("kvm: The guest lowcore is not mapped during interrupt "

			"delivery, killing userspace\n");

		do_exit(SIGKILL);

arch/s390/kvm/priv.c

+3 −3
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ static int handle_store_cpu_address(struct kvm_vcpu *vcpu) 
	}



	rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);

	if (rc == -EFAULT) {

	if (rc) {

		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

		goto out;

	}
@@ -230,7 +230,7 @@ static int handle_stfl(struct kvm_vcpu *vcpu) 


	rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),

			   &facility_list, sizeof(facility_list));

	if (rc == -EFAULT)

	if (rc)

		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

	else {

		VCPU_EVENT(vcpu, 5, "store facility list value %x",
@@ -348,7 +348,7 @@ static int handle_stidp(struct kvm_vcpu *vcpu) 
	}



	rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);

	if (rc == -EFAULT) {

	if (rc) {

		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

		goto out;

	}