On Mon, 10 Dec 2012 08:33:10 +0100
Alexander Graf <agraf@xxxxxxx> wrote:
>
> On 07.12.2012, at 13:30, Cornelia Huck wrote:
>
> > 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.
> >
> > Reviewed-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
> > Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
> > ---
> > Documentation/virtual/kvm/api.txt | 4 ++
> > arch/s390/include/asm/kvm_host.h | 2 +
> > arch/s390/kvm/interrupt.c | 115 ++++++++++++++++++++++++++++++++++++--
> > include/uapi/linux/kvm.h | 6 ++
> > 4 files changed, 122 insertions(+), 5 deletions(-)
> >
> > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> > index 6671fdc..e298a72 100644
> > --- a/Documentation/virtual/kvm/api.txt
> > +++ b/Documentation/virtual/kvm/api.txt
> > @@ -2068,6 +2068,10 @@ KVM_S390_INT_VIRTIO (vm) - virtio external interrupt; external interrupt
> > KVM_S390_INT_SERVICE (vm) - sclp external interrupt; sclp parameter in parm
> > KVM_S390_INT_EMERGENCY (vcpu) - sigp emergency; source cpu in parm
> > KVM_S390_INT_EXTERNAL_CALL (vcpu) - sigp external call; source cpu in parm
> > +KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) - compound value to indicate an
> > + I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel);
> > + I/O interruption parameters in parm (subchannel) and parm64 (intparm,
> > + interruption subclass)
> >
> > Note that the vcpu ioctl is asynchronous to vcpu execution.
> >
> > 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 c30615e..070ba22 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)) {
>
> Though I usually like if (...) { positive) } else { abort(); } coding style in general, it makes code quite hard to read when you are limited to 80 characters per line :)
>
> I think it'd really help readability if you instead would write
>
> if (!is_ioint(...)) {
> BUG();
> }
>
> and then continue without indent. That problem gets even more obvious further down the file.
Hm, "bad state last" seems to parse, though.
>
> > + 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();
>
> Please reverse the logic here, just like you did above :).
Hm, they're both the same?
>
> > }
> > }
> > @@ -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 "
> > @@ -545,7 +620,7 @@ 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);
> > @@ -569,9 +644,26 @@ 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);
> > @@ -579,7 +671,19 @@ 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) {
> > @@ -654,6 +758,7 @@ 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/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > index 494a84c..e676940 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -401,6 +401,12 @@ 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) \
>
> This one wants a comment saying that the namespace for everything not starting with 0xfffe/0xffff is taken by INT_IO.
Sounds reasonable.
>
>
> Alex
>
> > + (((schid)) | \
> > + ((ssid) << 16) | \
> > + ((cssid) << 18) | \
> > + ((ai) << 26))
> > +
> >
> > struct kvm_s390_interrupt {
> > __u32 type;
> > --
> > 1.7.12.4
> >
>
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