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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: Dominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@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 2015-10-19 16:24:28 +02:00 committed by Christian Borntraeger
parent 4bd33b5688
commit 71f116bfed
2 changed files with 24 additions and 42 deletions
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7
arch/s390/kvm/intercept.c
View File

@ -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);

59
arch/s390/kvm/kvm-s390.c
View File

@ -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 (kvm_arch_setup_async_pf(vcpu))
return 0;
return kvm_arch_fault_in_page(vcpu, current->thread.gmap_addr, 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);
}
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;
}