[PATCH v2 1/7] s390/kvm: Support for I/O interrupts.

Cornelia Huck
2012-09-04T15:13:24Z

Add support for handling I/O interrupts (standard, subchannel-related
ones and rudimentary adapter interrupts).

The subchannel-identifying parameters are encoded into the interrupt
type.

I/O interrupts are floating, so they can't be injected on a specific
vcpu.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
arch/s390/include/asm/kvm_host.h | 2 +
arch/s390/kvm/interrupt.c | 115 +++++++++++++++++++++++++++++++++++++--
include/linux/kvm.h | 6 ++
3 files changed, 118 insertions(+), 5 deletions(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index b784154..e47f697 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -76,6 +76,7 @@ struct kvm_s390_sie_block {
__u64 epoch; /* 0x0038 */
__u8 reserved40[4]; /* 0x0040 */
#define LCTL_CR0 0x8000
+#define LCTL_CR6 0x0200
__u16 lctl; /* 0x0044 */
__s16 icpua; /* 0x0046 */
__u32 ictl; /* 0x0048 */
@@ -127,6 +128,7 @@ struct kvm_vcpu_stat {
u32 deliver_prefix_signal;
u32 deliver_restart_signal;
u32 deliver_program_int;
+ u32 deliver_io_int;
u32 exit_wait_state;
u32 instruction_stidp;
u32 instruction_spx;
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 7556231..1dccfe7 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -21,11 +21,26 @@
#include "gaccess.h"
#include "trace-s390.h"

+#define IOINT_SCHID_MASK 0x0000ffff
+#define IOINT_SSID_MASK 0x00030000
+#define IOINT_CSSID_MASK 0x03fc0000
+#define IOINT_AI_MASK 0x04000000
+
+static int is_ioint(u64 type)
+{
+ return ((type & 0xfffe0000u) != 0xfffe0000u);
+}
+
static int psw_extint_disabled(struct kvm_vcpu *vcpu)
{
return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT);
}

+static int psw_ioint_disabled(struct kvm_vcpu *vcpu)
+{
+ return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_IO);
+}
+
static int psw_interrupts_disabled(struct kvm_vcpu *vcpu)
{
if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) ||
@@ -68,7 +83,18 @@ static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,
case KVM_S390_RESTART:
return 1;
default:
- BUG();
+ if (is_ioint(inti->type)) {
+ if (psw_ioint_disabled(vcpu))
+ return 0;
+ if (vcpu->arch.sie_block->gcr[6] &
+ inti->io.io_int_word)
+ return 1;
+ return 0;
+ } else {
+ printk(KERN_WARNING "illegal interrupt type %llx\n",
+ inti->type);
+ BUG();
+ }
}
return 0;
}
@@ -117,6 +143,13 @@ static void __set_intercept_indicator(struct kvm_vcpu *vcpu,
__set_cpuflag(vcpu, CPUSTAT_STOP_INT);
break;
default:
+ if (is_ioint(inti->type)) {
+ if (psw_ioint_disabled(vcpu))
+ __set_cpuflag(vcpu, CPUSTAT_IO_INT);
+ else
+ vcpu->arch.sie_block->lctl |= LCTL_CR6;
+ break;
+ }
BUG();
}
}
@@ -298,7 +331,49 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu,
break;

default:
- BUG();
+ if (is_ioint(inti->type)) {
+ __u32 param0 = ((__u32)inti->io.subchannel_id << 16) |
+ inti->io.subchannel_nr;
+ __u64 param1 = ((__u64)inti->io.io_int_parm << 32) |
+ inti->io.io_int_word;
+ VCPU_EVENT(vcpu, 4,
+ "interrupt: I/O %llx", inti->type);
+ vcpu->stat.deliver_io_int++;
+ trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id, inti->type,
+ 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,
+ inti->io.subchannel_nr);
+ if (rc == -EFAULT)
+ exception = 1;
+
+ 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,
+ inti->io.io_int_word);
+ if (rc == -EFAULT)
+ exception = 1;
+
+ 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,
+ __LC_IO_NEW_PSW, sizeof(psw_t));
+ if (rc == -EFAULT)
+ exception = 1;
+ break;
+ } else
+ BUG();
}
if (exception) {
printk("kvm: The guest lowcore is not mapped during interrupt "
@@ -547,7 +622,7 @@ int kvm_s390_inject_vm(struct kvm *kvm,
{
struct kvm_s390_local_interrupt *li;
struct kvm_s390_float_interrupt *fi;
- struct kvm_s390_interrupt_info *inti;
+ struct kvm_s390_interrupt_info *inti, *iter;
int sigcpu;

inti = kzalloc(sizeof(*inti), GFP_KERNEL);
@@ -571,9 +646,26 @@ int kvm_s390_inject_vm(struct kvm *kvm,
case KVM_S390_SIGP_STOP:
case KVM_S390_INT_EXTERNAL_CALL:
case KVM_S390_INT_EMERGENCY:
- default:
kfree(inti);
return -EINVAL;
+ default:
+ if (!is_ioint(s390int->type)) {
+ kfree(inti);
+ return -EINVAL;
+ }
+ if (s390int->type & IOINT_AI_MASK)
+ VM_EVENT(kvm, 5, "%s", "inject: I/O (AI)");
+ else
+ VM_EVENT(kvm, 5, "inject: I/O css %x ss %x schid %04x",
+ s390int->type & IOINT_CSSID_MASK,
+ s390int->type & IOINT_SSID_MASK,
+ s390int->type & IOINT_SCHID_MASK);
+ inti->type = s390int->type;
+ inti->io.subchannel_id = s390int->parm >> 16;
+ inti->io.subchannel_nr = s390int->parm & 0x0000ffffu;
+ inti->io.io_int_parm = s390int->parm64 >> 32;
+ inti->io.io_int_word = s390int->parm64 & 0x00000000ffffffffull;
+ break;
}
trace_kvm_s390_inject_vm(s390int->type, s390int->parm, s390int->parm64,
2);
@@ -581,7 +673,19 @@ int kvm_s390_inject_vm(struct kvm *kvm,
mutex_lock(&kvm->lock);
fi = &kvm->arch.float_int;
spin_lock(&fi->lock);
- list_add_tail(&inti->list, &fi->list);
+ if (!is_ioint(inti->type))
+ list_add_tail(&inti->list, &fi->list);
+ else {
+ /* 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)
+ continue;
+ break;
+ }
+ list_add_tail(&inti->list, &iter->list);
+ }
atomic_set(&fi->active, 1);
sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS);
if (sigcpu == KVM_MAX_VCPUS) {
@@ -639,6 +743,7 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
case KVM_S390_INT_VIRTIO:
case KVM_S390_INT_SERVICE:
default:
+ /* also includes IOINT */
kfree(inti);
return -EINVAL;
}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index d808694..5a36e65 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -396,6 +396,12 @@ struct kvm_s390_psw {
#define KVM_S390_INT_SERVICE 0xffff2401u
#define KVM_S390_INT_EMERGENCY 0xffff1201u
#define KVM_S390_INT_EXTERNAL_CALL 0xffff1202u
+#define KVM_S390_INT_IO(ai,cssid,ssid,schid) \
+ (((schid)) | \
+ ((ssid) << 16) | \
+ ((cssid) << 18) | \
+ ((ai) << 26))
+

struct kvm_s390_interrupt {
__u32 type;
--
1.7.11.5