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: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Cornelia Huck 2013-02-07 13:20:52 +01:00 committed by Gleb Natapov
parent 24db2734ad
commit 79fd50c67f

View File

@ -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;
}