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Commit adbf1698 authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
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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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 1b7029be

arch/s390/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

arch/s390/kvm/interrupt.c

+5 −0
Original line number Diff line number Diff line
@@ -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)

arch/s390/kvm/kvm-s390.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/s390/kvm/vsie.c

+35 −0
Original line number Diff line number Diff line
@@ -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);

	}

}