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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>
This commit is contained in:
Cornelia Huck 2012-12-20 15:32:12 +01:00 committed by Marcelo Tosatti
parent d6712df95b
commit fa6b7fe992
10 changed files with 202 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
Documentation/virtual/kvm/api.txt
View File

@ -2350,6 +2350,22 @@ The possible hypercalls are defined in the Power Architecture Platform
Requirements (PAPR) document available from www.power.org (free
developer registration required to access it).
/* KVM_EXIT_S390_TSCH */
struct {
__u16 subchannel_id;
__u16 subchannel_nr;
__u32 io_int_parm;
__u32 io_int_word;
__u32 ipb;
__u8 dequeued;
} s390_tsch;
s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled
and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O
interrupt for the target subchannel has been dequeued and subchannel_id,
subchannel_nr, io_int_parm and io_int_word contain the parameters for that
interrupt. ipb is needed for instruction parameter decoding.
/* Fix the size of the union. */
char padding[256];
};
@ -2471,3 +2487,17 @@ For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV:
where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value.
- The tsize field of mas1 shall be set to 4K on TLB0, even though the
hardware ignores this value for TLB0.
6.4 KVM_CAP_S390_CSS_SUPPORT
Architectures: s390
Parameters: none
Returns: 0 on success; -1 on error
This capability enables support for handling of channel I/O instructions.
TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are
handled in-kernel, while the other I/O instructions are passed to userspace.
When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST
SUBCHANNEL intercepts.

1
arch/s390/include/asm/kvm_host.h
View File

@ -262,6 +262,7 @@ struct kvm_arch{
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 *);

1
arch/s390/kvm/intercept.c
View File

@ -264,6 +264,7 @@ static const intercept_handler_t intercept_funcs[] = {
[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,

37
arch/s390/kvm/interrupt.c
View File

@ -709,6 +709,43 @@ int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code)
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)
{

12
arch/s390/kvm/kvm-s390.c
View File

@ -141,6 +141,7 @@ int kvm_dev_ioctl_check_extension(long ext)
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 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
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 @@ rerun_vcpu:
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 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
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;

2
arch/s390/kvm/kvm-s390.h
View File

@ -113,6 +113,8 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
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);

91
arch/s390/kvm/priv.c
View File

@ -127,13 +127,96 @@ static int handle_skey(struct kvm_vcpu *vcpu)
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)

20
arch/s390/kvm/trace-s390.h
View File

@ -204,6 +204,26 @@ TRACE_EVENT(kvm_s390_stop_request,
);
/*
* 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 */

2
include/trace/events/kvm.h
View File

@ -14,7 +14,7 @@
ERSN(SHUTDOWN), ERSN(FAIL_ENTRY), ERSN(INTR), ERSN(SET_TPR), \
ERSN(TPR_ACCESS), ERSN(S390_SIEIC), ERSN(S390_RESET), ERSN(DCR),\
ERSN(NMI), ERSN(INTERNAL_ERROR), ERSN(OSI), ERSN(PAPR_HCALL), \
ERSN(S390_UCONTROL)
ERSN(S390_UCONTROL), ERSN(S390_TSCH)
TRACE_EVENT(kvm_userspace_exit,
TP_PROTO(__u32 reason, int errno),

11
include/uapi/linux/kvm.h
View File

@ -168,6 +168,7 @@ struct kvm_pit_config {
#define KVM_EXIT_PAPR_HCALL 19
#define KVM_EXIT_S390_UCONTROL 20
#define KVM_EXIT_WATCHDOG 21
#define KVM_EXIT_S390_TSCH 22
/* For KVM_EXIT_INTERNAL_ERROR */
/* Emulate instruction failed. */
@ -285,6 +286,15 @@ struct kvm_run {
__u64 ret;
__u64 args[9];
} papr_hcall;
/* KVM_EXIT_S390_TSCH */
struct {
__u16 subchannel_id;
__u16 subchannel_nr;
__u32 io_int_parm;
__u32 io_int_word;
__u32 ipb;
__u8 dequeued;
} s390_tsch;
/* Fix the size of the union. */
char padding[256];
};
@ -645,6 +655,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_IRQFD_RESAMPLE 82
#define KVM_CAP_PPC_BOOKE_WATCHDOG 83
#define KVM_CAP_PPC_HTAB_FD 84
#define KVM_CAP_S390_CSS_SUPPORT 85
#ifdef KVM_CAP_IRQ_ROUTING