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Commit 71f116bf authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
Browse files

KVM: s390: rewrite vcpu_post_run and drop out early 



Let's rewrite this function to better reflect how we actually handle
exit_code. By dropping out early we can save a few cycles. This
especially speeds up sie exits caused by host irqs.

Also, let's move the special -EOPNOTSUPP for intercepts to
the place where it belongs and convert it to -EREMOTE.

Reviewed-by: default avatarDominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@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 4bd33b56

arch/s390/kvm/intercept.c

+3 −4
Original line number Diff line number Diff line
@@ -54,9 +54,6 @@ void kvm_s390_rewind_psw(struct kvm_vcpu *vcpu, int ilc) 
static int handle_noop(struct kvm_vcpu *vcpu)

{

	switch (vcpu->arch.sie_block->icptcode) {

	case 0x0:

		vcpu->stat.exit_null++;

		break;

	case 0x10:

		vcpu->stat.exit_external_request++;

		break;
@@ -338,8 +335,10 @@ static int handle_partial_execution(struct kvm_vcpu *vcpu) 


int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)

{

	if (kvm_is_ucontrol(vcpu->kvm))

		return -EOPNOTSUPP;



	switch (vcpu->arch.sie_block->icptcode) {

	case 0x00:

	case 0x10:

	case 0x18:

		return handle_noop(vcpu);

arch/s390/kvm/kvm-s390.c

+21 −38
Original line number Diff line number Diff line
@@ -2071,8 +2071,6 @@ static int vcpu_post_run_fault_in_sie(struct kvm_vcpu *vcpu) 


static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)

{

	int rc = -1;



	VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",

		   vcpu->arch.sie_block->icptcode);

	trace_kvm_s390_sie_exit(vcpu, vcpu->arch.sie_block->icptcode);
@@ -2080,40 +2078,35 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason) 
	if (guestdbg_enabled(vcpu))

		kvm_s390_restore_guest_per_regs(vcpu);



	if (exit_reason >= 0) {

		rc = 0;

	memcpy(&vcpu->run->s.regs.gprs[14], &vcpu->arch.sie_block->gg14, 16);



	if (vcpu->arch.sie_block->icptcode > 0) {

		int rc = kvm_handle_sie_intercept(vcpu);



		if (rc != -EOPNOTSUPP)

			return rc;

		vcpu->run->exit_reason = KVM_EXIT_S390_SIEIC;

		vcpu->run->s390_sieic.icptcode = vcpu->arch.sie_block->icptcode;

		vcpu->run->s390_sieic.ipa = vcpu->arch.sie_block->ipa;

		vcpu->run->s390_sieic.ipb = vcpu->arch.sie_block->ipb;

		return -EREMOTE;

	} else if (exit_reason != -EFAULT) {

		vcpu->stat.exit_null++;

		return 0;

	} else if (kvm_is_ucontrol(vcpu->kvm)) {

		vcpu->run->exit_reason = KVM_EXIT_S390_UCONTROL;

		vcpu->run->s390_ucontrol.trans_exc_code =

						current->thread.gmap_addr;

		vcpu->run->s390_ucontrol.pgm_code = 0x10;

		rc = -EREMOTE;



		return -EREMOTE;

	} else if (current->thread.gmap_pfault) {

		trace_kvm_s390_major_guest_pfault(vcpu);

		current->thread.gmap_pfault = 0;

		if (kvm_arch_setup_async_pf(vcpu)) {

			rc = 0;

		} else {

			gpa_t gpa = current->thread.gmap_addr;

			rc = kvm_arch_fault_in_page(vcpu, gpa, 1);

		}

	}



	if (rc == -1)

		rc = vcpu_post_run_fault_in_sie(vcpu);



	memcpy(&vcpu->run->s.regs.gprs[14], &vcpu->arch.sie_block->gg14, 16);



	if (rc == 0) {

		if (kvm_is_ucontrol(vcpu->kvm))

			/* Don't exit for host interrupts. */

			rc = vcpu->arch.sie_block->icptcode ? -EOPNOTSUPP : 0;

		else

			rc = kvm_handle_sie_intercept(vcpu);

		if (kvm_arch_setup_async_pf(vcpu))

			return 0;

		return kvm_arch_fault_in_page(vcpu, current->thread.gmap_addr, 1);

	}



	return rc;

	return vcpu_post_run_fault_in_sie(vcpu);

}



static int __vcpu_run(struct kvm_vcpu *vcpu)
@@ -2233,18 +2226,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
		rc = 0;

	}



	if (rc == -EOPNOTSUPP) {

		/* intercept cannot be handled in-kernel, prepare kvm-run */

		kvm_run->exit_reason         = KVM_EXIT_S390_SIEIC;

		kvm_run->s390_sieic.icptcode = vcpu->arch.sie_block->icptcode;

		kvm_run->s390_sieic.ipa      = vcpu->arch.sie_block->ipa;

		kvm_run->s390_sieic.ipb      = vcpu->arch.sie_block->ipb;

		rc = 0;

	}



	if (rc == -EREMOTE) {

		/* intercept was handled, but userspace support is needed

		 * kvm_run has been prepared by the handler */

		/* userspace support is needed, kvm_run has been prepared */

		rc = 0;

	}