KVM: s390: Add support for channel I/O instructions.
Add a new capability, KVM_CAP_S390_CSS_SUPPORT, which will pass
intercepts for channel I/O instructions to userspace. Only I/O
instructions interacting with I/O interrupts need to be handled
in-kernel:
- TEST PENDING INTERRUPTION (tpi) dequeues and stores pending
interrupts entirely in-kernel.
- TEST SUBCHANNEL (tsch) dequeues pending interrupts in-kernel
and exits via KVM_EXIT_S390_TSCH to userspace for subchannel-
related processing.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 29363d1..16bd5d1 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -262,6 +262,7 @@
debug_info_t *dbf;
struct kvm_s390_float_interrupt float_int;
struct gmap *gmap;
+ int css_support;
};
extern int sie64a(struct kvm_s390_sie_block *, u64 *);
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 71af87d..f26ff1e 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -264,6 +264,7 @@
[0x0C >> 2] = handle_instruction_and_prog,
[0x10 >> 2] = handle_noop,
[0x14 >> 2] = handle_noop,
+ [0x18 >> 2] = handle_noop,
[0x1C >> 2] = kvm_s390_handle_wait,
[0x20 >> 2] = handle_validity,
[0x28 >> 2] = handle_stop,
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index b3b4748..9a12835 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -709,6 +709,43 @@
return 0;
}
+struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm,
+ u64 cr6, u64 schid)
+{
+ struct kvm_s390_float_interrupt *fi;
+ struct kvm_s390_interrupt_info *inti, *iter;
+
+ if ((!schid && !cr6) || (schid && cr6))
+ return NULL;
+ mutex_lock(&kvm->lock);
+ fi = &kvm->arch.float_int;
+ spin_lock(&fi->lock);
+ inti = NULL;
+ list_for_each_entry(iter, &fi->list, list) {
+ if (!is_ioint(iter->type))
+ continue;
+ if (cr6 && ((cr6 & iter->io.io_int_word) == 0))
+ continue;
+ if (schid) {
+ if (((schid & 0x00000000ffff0000) >> 16) !=
+ iter->io.subchannel_id)
+ continue;
+ if ((schid & 0x000000000000ffff) !=
+ iter->io.subchannel_nr)
+ continue;
+ }
+ inti = iter;
+ break;
+ }
+ if (inti)
+ list_del_init(&inti->list);
+ if (list_empty(&fi->list))
+ atomic_set(&fi->active, 0);
+ spin_unlock(&fi->lock);
+ mutex_unlock(&kvm->lock);
+ return inti;
+}
+
int kvm_s390_inject_vm(struct kvm *kvm,
struct kvm_s390_interrupt *s390int)
{
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 5ff2603..5b01f09 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -141,6 +141,7 @@
case KVM_CAP_SYNC_REGS:
case KVM_CAP_ONE_REG:
case KVM_CAP_ENABLE_CAP:
+ case KVM_CAP_S390_CSS_SUPPORT:
r = 1;
break;
case KVM_CAP_NR_VCPUS:
@@ -235,6 +236,9 @@
if (!kvm->arch.gmap)
goto out_nogmap;
}
+
+ kvm->arch.css_support = 0;
+
return 0;
out_nogmap:
debug_unregister(kvm->arch.dbf);
@@ -658,6 +662,7 @@
case KVM_EXIT_INTR:
case KVM_EXIT_S390_RESET:
case KVM_EXIT_S390_UCONTROL:
+ case KVM_EXIT_S390_TSCH:
break;
default:
BUG();
@@ -818,6 +823,13 @@
return -EINVAL;
switch (cap->cap) {
+ case KVM_CAP_S390_CSS_SUPPORT:
+ if (!vcpu->kvm->arch.css_support) {
+ vcpu->kvm->arch.css_support = 1;
+ trace_kvm_s390_enable_css(vcpu->kvm);
+ }
+ r = 0;
+ break;
default:
r = -EINVAL;
break;
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 211b340..3e05def 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -113,6 +113,8 @@
struct kvm_s390_interrupt *s390int);
int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
int kvm_s390_inject_sigp_stop(struct kvm_vcpu *vcpu, int action);
+struct kvm_s390_interrupt_info *kvm_s390_get_io_int(struct kvm *kvm,
+ u64 cr6, u64 schid);
/* implemented in priv.c */
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu);
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 8ad776f..0ef9894 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -127,13 +127,96 @@
return 0;
}
+static int handle_tpi(struct kvm_vcpu *vcpu)
+{
+ u64 addr;
+ struct kvm_s390_interrupt_info *inti;
+ int cc;
+
+ addr = kvm_s390_get_base_disp_s(vcpu);
+
+ inti = kvm_s390_get_io_int(vcpu->kvm, vcpu->run->s.regs.crs[6], 0);
+ if (inti) {
+ if (addr) {
+ /*
+ * Store the two-word I/O interruption code into the
+ * provided area.
+ */
+ put_guest_u16(vcpu, addr, inti->io.subchannel_id);
+ put_guest_u16(vcpu, addr + 2, inti->io.subchannel_nr);
+ put_guest_u32(vcpu, addr + 4, inti->io.io_int_parm);
+ } else {
+ /*
+ * Store the three-word I/O interruption code into
+ * the appropriate lowcore area.
+ */
+ put_guest_u16(vcpu, 184, inti->io.subchannel_id);
+ put_guest_u16(vcpu, 186, inti->io.subchannel_nr);
+ put_guest_u32(vcpu, 188, inti->io.io_int_parm);
+ put_guest_u32(vcpu, 192, inti->io.io_int_word);
+ }
+ cc = 1;
+ } else
+ cc = 0;
+ kfree(inti);
+ /* Set condition code and we're done. */
+ vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+ vcpu->arch.sie_block->gpsw.mask |= (cc & 3ul) << 44;
+ return 0;
+}
+
+static int handle_tsch(struct kvm_vcpu *vcpu)
+{
+ struct kvm_s390_interrupt_info *inti;
+
+ inti = kvm_s390_get_io_int(vcpu->kvm, 0,
+ vcpu->run->s.regs.gprs[1]);
+
+ /*
+ * Prepare exit to userspace.
+ * We indicate whether we dequeued a pending I/O interrupt
+ * so that userspace can re-inject it if the instruction gets
+ * a program check. While this may re-order the pending I/O
+ * interrupts, this is no problem since the priority is kept
+ * intact.
+ */
+ vcpu->run->exit_reason = KVM_EXIT_S390_TSCH;
+ vcpu->run->s390_tsch.dequeued = !!inti;
+ if (inti) {
+ vcpu->run->s390_tsch.subchannel_id = inti->io.subchannel_id;
+ vcpu->run->s390_tsch.subchannel_nr = inti->io.subchannel_nr;
+ vcpu->run->s390_tsch.io_int_parm = inti->io.io_int_parm;
+ vcpu->run->s390_tsch.io_int_word = inti->io.io_int_word;
+ }
+ vcpu->run->s390_tsch.ipb = vcpu->arch.sie_block->ipb;
+ kfree(inti);
+ return -EREMOTE;
+}
+
static int handle_io_inst(struct kvm_vcpu *vcpu)
{
VCPU_EVENT(vcpu, 4, "%s", "I/O instruction");
- /* condition code 3 */
- vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
- vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
- return 0;
+
+ if (vcpu->kvm->arch.css_support) {
+ /*
+ * Most I/O instructions will be handled by userspace.
+ * Exceptions are tpi and the interrupt portion of tsch.
+ */
+ if (vcpu->arch.sie_block->ipa == 0xb236)
+ return handle_tpi(vcpu);
+ if (vcpu->arch.sie_block->ipa == 0xb235)
+ return handle_tsch(vcpu);
+ /* Handle in userspace. */
+ return -EOPNOTSUPP;
+ } else {
+ /*
+ * Set condition code 3 to stop the guest from issueing channel
+ * I/O instructions.
+ */
+ vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+ vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
+ return 0;
+ }
}
static int handle_stfl(struct kvm_vcpu *vcpu)
diff --git a/arch/s390/kvm/trace-s390.h b/arch/s390/kvm/trace-s390.h
index 95fbc1ab..13f30f5 100644
--- a/arch/s390/kvm/trace-s390.h
+++ b/arch/s390/kvm/trace-s390.h
@@ -204,6 +204,26 @@
);
+/*
+ * Trace point for enabling channel I/O instruction support.
+ */
+TRACE_EVENT(kvm_s390_enable_css,
+ TP_PROTO(void *kvm),
+ TP_ARGS(kvm),
+
+ TP_STRUCT__entry(
+ __field(void *, kvm)
+ ),
+
+ TP_fast_assign(
+ __entry->kvm = kvm;
+ ),
+
+ TP_printk("enabling channel I/O support (kvm @ %p)\n",
+ __entry->kvm)
+ );
+
+
#endif /* _TRACE_KVMS390_H */
/* This part must be outside protection */