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KVM: s390: Beautify skey enable check 

Let's introduce an explicit check if skeys have already been enabled
for the vcpu, so we don't have to check the mm context if we don't have
the storage key facility.

This lets us check for enablement without having to take the mm
semaphore and thus speedup skey emulation.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Janosch Frank 2018-07-20 13:51:21 +01:00 committed by Christian Borntraeger
parent a3da7b4a3b
commit 57cb198cfd
2 changed files with 5 additions and 6 deletions
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1
arch/s390/include/asm/kvm_host.h
View File

@ -656,6 +656,7 @@ struct kvm_vcpu_arch {
seqcount_t cputm_seqcount;
__u64 cputm_start;
bool gs_enabled;
bool skey_enabled;
};
struct kvm_vm_stat {

10
arch/s390/kvm/priv.c
View File

@ -205,13 +205,10 @@ static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
int kvm_s390_skey_check_enable(struct kvm_vcpu *vcpu)
{
int rc;
struct kvm_s390_sie_block *sie_block = vcpu->arch.sie_block;
trace_kvm_s390_skey_related_inst(vcpu);
/* Already enabled? */
if (vcpu->kvm->arch.use_skf &&
!(sie_block->ictl & (ICTL_ISKE | ICTL_SSKE | ICTL_RRBE)) &&
!kvm_s390_test_cpuflags(vcpu, CPUSTAT_KSS))
if (vcpu->arch.skey_enabled)
return 0;
rc = s390_enable_skey();
@ -222,9 +219,10 @@ int kvm_s390_skey_check_enable(struct kvm_vcpu *vcpu)
if (kvm_s390_test_cpuflags(vcpu, CPUSTAT_KSS))
kvm_s390_clear_cpuflags(vcpu, CPUSTAT_KSS);
if (!vcpu->kvm->arch.use_skf)
sie_block->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
vcpu->arch.sie_block->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
else
sie_block->ictl &= ~(ICTL_ISKE | ICTL_SSKE | ICTL_RRBE);
vcpu->arch.sie_block->ictl &= ~(ICTL_ISKE | ICTL_SSKE | ICTL_RRBE);
vcpu->arch.skey_enabled = true;
return 0;
}