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KVM: s390: add functions to (un)register GISC with GISA

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Add the Interruption Alert Mask (IAM) to the architecture specific
kvm struct. This mask in the GISA is used to define for which ISC
a GIB alert will be issued.

The functions kvm_s390_gisc_register() and kvm_s390_gisc_unregister()
are used to (un)register a GISC (guest ISC) with a virtual machine and
its GISA.

Upon successful completion, kvm_s390_gisc_register() returns the
ISC to be used for GIB alert interruptions. A negative return code
indicates an error during registration.

Theses functions will be used by other adapter types like AP and PCI to
request pass-through interruption support.

Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20190131085247.13826-12-mimu@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Michael Mueller 2019-01-31 09:52:42 +01:00 committed by Christian Borntraeger
parent 25c84dbaec
commit 6cff2e1046
2 changed files with 125 additions and 0 deletions
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13
arch/s390/include/asm/kvm_host.h
View File

@ -781,6 +781,9 @@ struct kvm_s390_gisa {
u8 reserved03[11];
u32 airq_count;
} g1;
struct {
u64 word[4];
} u64;
};
};
@ -813,8 +816,15 @@ struct kvm_s390_vsie {
struct page *pages[KVM_MAX_VCPUS];
};
struct kvm_s390_gisa_iam {
u8 mask;
spinlock_t ref_lock;
u32 ref_count[MAX_ISC + 1];
};
struct kvm_s390_gisa_interrupt {
struct kvm_s390_gisa *origin;
struct kvm_s390_gisa_iam alert;
};
struct kvm_arch{
@ -885,6 +895,9 @@ void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
extern int sie64a(struct kvm_s390_sie_block *, u64 *);
extern char sie_exit;
extern int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc);
extern int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc);
static inline void kvm_arch_hardware_disable(void) {}
static inline void kvm_arch_check_processor_compat(void *rtn) {}
static inline void kvm_arch_sync_events(struct kvm *kvm) {}

112
arch/s390/kvm/interrupt.c
View File

@ -222,6 +222,33 @@ static inline u8 int_word_to_isc(u32 int_word)
*/
#define IPM_BIT_OFFSET (offsetof(struct kvm_s390_gisa, ipm) * BITS_PER_BYTE)
/**
* gisa_set_iam - change the GISA interruption alert mask
*
* @gisa: gisa to operate on
* @iam: new IAM value to use
*
* Change the IAM atomically with the next alert address and the IPM
* of the GISA if the GISA is not part of the GIB alert list. All three
* fields are located in the first long word of the GISA.
*
* Returns: 0 on success
* -EBUSY in case the gisa is part of the alert list
*/
static inline int gisa_set_iam(struct kvm_s390_gisa *gisa, u8 iam)
{
u64 word, _word;
do {
word = READ_ONCE(gisa->u64.word[0]);
if ((u64)gisa != word >> 32)
return -EBUSY;
_word = (word & ~0xffUL) | iam;
} while (cmpxchg(&gisa->u64.word[0], word, _word) != word);
return 0;
}
static inline void gisa_set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc)
{
set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa);
@ -2911,6 +2938,8 @@ void kvm_s390_gisa_init(struct kvm *kvm)
if (!css_general_characteristics.aiv)
return;
gi->origin = &kvm->arch.sie_page2->gisa;
gi->alert.mask = 0;
spin_lock_init(&gi->alert.ref_lock);
kvm_s390_gisa_clear(kvm);
VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin);
}
@ -2920,6 +2949,89 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
kvm->arch.gisa_int.origin = NULL;
}
/**
* kvm_s390_gisc_register - register a guest ISC
*
* @kvm: the kernel vm to work with
* @gisc: the guest interruption sub class to register
*
* The function extends the vm specific alert mask to use.
* The effective IAM mask in the GISA is updated as well
* in case the GISA is not part of the GIB alert list.
* It will be updated latest when the IAM gets restored
* by gisa_get_ipm_or_restore_iam().
*
* Returns: the nonspecific ISC (NISC) the gib alert mechanism
* has registered with the channel subsystem.
* -ENODEV in case the vm uses no GISA
* -ERANGE in case the guest ISC is invalid
*/
int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc)
{
struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
if (!gi->origin)
return -ENODEV;
if (gisc > MAX_ISC)
return -ERANGE;
spin_lock(&gi->alert.ref_lock);
gi->alert.ref_count[gisc]++;
if (gi->alert.ref_count[gisc] == 1) {
gi->alert.mask |= 0x80 >> gisc;
gisa_set_iam(gi->origin, gi->alert.mask);
}
spin_unlock(&gi->alert.ref_lock);
return gib->nisc;
}
EXPORT_SYMBOL_GPL(kvm_s390_gisc_register);
/**
* kvm_s390_gisc_unregister - unregister a guest ISC
*
* @kvm: the kernel vm to work with
* @gisc: the guest interruption sub class to register
*
* The function reduces the vm specific alert mask to use.
* The effective IAM mask in the GISA is updated as well
* in case the GISA is not part of the GIB alert list.
* It will be updated latest when the IAM gets restored
* by gisa_get_ipm_or_restore_iam().
*
* Returns: the nonspecific ISC (NISC) the gib alert mechanism
* has registered with the channel subsystem.
* -ENODEV in case the vm uses no GISA
* -ERANGE in case the guest ISC is invalid
* -EINVAL in case the guest ISC is not registered
*/
int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc)
{
struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
int rc = 0;
if (!gi->origin)
return -ENODEV;
if (gisc > MAX_ISC)
return -ERANGE;
spin_lock(&gi->alert.ref_lock);
if (gi->alert.ref_count[gisc] == 0) {
rc = -EINVAL;
goto out;
}
gi->alert.ref_count[gisc]--;
if (gi->alert.ref_count[gisc] == 0) {
gi->alert.mask &= ~(0x80 >> gisc);
gisa_set_iam(gi->origin, gi->alert.mask);
}
out:
spin_unlock(&gi->alert.ref_lock);
return rc;
}
EXPORT_SYMBOL_GPL(kvm_s390_gisc_unregister);
void kvm_s390_gib_destroy(void)
{
if (!gib)