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Commit 79fd50c6 authored by Cornelia Huck's avatar Cornelia Huck Committed by Gleb Natapov
Browse files

KVM: s390: Fix handling of iscs. 



There are two ways to express an interruption subclass:
- As a bitmask, as used in cr6.
- As a number, as used in the I/O interruption word.

Unfortunately, we have treated the I/O interruption word as if it
contained the bitmask as well, which went unnoticed so far as
- (not-yet-released) qemu made the same mistake, and
- Linux guest kernels don't check the isc value in the I/O interruption
  word for subchannel interrupts.

Make sure that we treat the I/O interruption word correctly.

Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 24db2734

arch/s390/kvm/interrupt.c

+15 −3
Original line number Diff line number Diff line
@@ -55,6 +55,13 @@ static int psw_interrupts_disabled(struct kvm_vcpu *vcpu) 
	return 1;

}



static u64 int_word_to_isc_bits(u32 int_word)

{

	u8 isc = (int_word & 0x38000000) >> 27;



	return (0x80 >> isc) << 24;

}



static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,

				      struct kvm_s390_interrupt_info *inti)

{
@@ -96,7 +103,8 @@ static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu, 
	case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:

		if (psw_ioint_disabled(vcpu))

			return 0;

		if (vcpu->arch.sie_block->gcr[6] & inti->io.io_int_word)

		if (vcpu->arch.sie_block->gcr[6] &

		    int_word_to_isc_bits(inti->io.io_int_word))

			return 1;

		return 0;

	default:
@@ -724,7 +732,8 @@ struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm, 
	list_for_each_entry(iter, &fi->list, list) {

		if (!is_ioint(iter->type))

			continue;

		if (cr6 && ((cr6 & iter->io.io_int_word) == 0))

		if (cr6 &&

		    ((cr6 & int_word_to_isc_bits(iter->io.io_int_word)) == 0))

			continue;

		if (schid) {

			if (((schid & 0x00000000ffff0000) >> 16) !=
@@ -811,11 +820,14 @@ int kvm_s390_inject_vm(struct kvm *kvm, 
	if (!is_ioint(inti->type))

		list_add_tail(&inti->list, &fi->list);

	else {

		u64 isc_bits = int_word_to_isc_bits(inti->io.io_int_word);



		/* Keep I/O interrupts sorted in isc order. */

		list_for_each_entry(iter, &fi->list, list) {

			if (!is_ioint(iter->type))

				continue;

			if (iter->io.io_int_word <= inti->io.io_int_word)

			if (int_word_to_isc_bits(iter->io.io_int_word)

			    <= isc_bits)

				continue;

			break;

		}