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KVM: s390: vsie: speed up VCPU irq delivery when handling vsie 

Whenever we want to wake up a VCPU (e.g. when injecting an IRQ), we
have to kick it out of vsie, so the request will be handled faster.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
David Hildenbrand 2016-05-27 22:03:52 +02:00 committed by Christian Borntraeger
parent 1b7029bec1
commit adbf16985c
4 changed files with 43 additions and 0 deletions
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2
arch/s390/include/asm/kvm_host.h
View File

@ -549,6 +549,8 @@ struct kvm_guestdbg_info_arch {
struct kvm_vcpu_arch {
struct kvm_s390_sie_block *sie_block;
/* if vsie is active, currently executed shadow sie control block */
struct kvm_s390_sie_block *vsie_block;
unsigned int host_acrs[NUM_ACRS];
struct fpu host_fpregs;
struct kvm_s390_local_interrupt local_int;

5
arch/s390/kvm/interrupt.c
View File

@ -995,6 +995,11 @@ void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu)
swake_up(&vcpu->wq);
vcpu->stat.halt_wakeup++;
}
/*
* The VCPU might not be sleeping but is executing the VSIE. Let's
* kick it, so it leaves the SIE to process the request.
*/
kvm_s390_vsie_kick(vcpu);
}
enum hrtimer_restart kvm_s390_idle_wakeup(struct hrtimer *timer)

1
arch/s390/kvm/kvm-s390.h
View File

@ -254,6 +254,7 @@ int kvm_s390_handle_eb(struct kvm_vcpu *vcpu);
/* implemented in vsie.c */
int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu);
void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu);
void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
unsigned long end);
void kvm_s390_vsie_init(struct kvm *kvm);

35
arch/s390/kvm/vsie.c
View File

@ -837,6 +837,23 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
return 0;
}
/*
* Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
*/
static void register_shadow_scb(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
}
/*
* Unregister a shadow scb from a VCPU.
*/
static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
{
WRITE_ONCE(vcpu->arch.vsie_block, NULL);
}
/*
* Run the vsie on a shadowed scb, managing the gmap shadow, handling
* prefix pages and faults.
@ -860,6 +877,7 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
rc = do_vsie_run(vcpu, vsie_page);
gmap_enable(vcpu->arch.gmap);
}
atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
if (rc == -EAGAIN)
rc = 0;
@ -1000,7 +1018,9 @@ int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
rc = pin_blocks(vcpu, vsie_page);
if (rc)
goto out_unshadow;
register_shadow_scb(vcpu, vsie_page);
rc = vsie_run(vcpu, vsie_page);
unregister_shadow_scb(vcpu);
unpin_blocks(vcpu, vsie_page);
out_unshadow:
unshadow_scb(vcpu, vsie_page);
@ -1039,3 +1059,18 @@ void kvm_s390_vsie_destroy(struct kvm *kvm)
kvm->arch.vsie.page_count = 0;
mutex_unlock(&kvm->arch.vsie.mutex);
}
void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
{
struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
/*
* Even if the VCPU lets go of the shadow sie block reference, it is
* still valid in the cache. So we can safely kick it.
*/
if (scb) {
atomic_or(PROG_BLOCK_SIE, &scb->prog20);
if (scb->prog0c & PROG_IN_SIE)
atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
}
}