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Commit 57cb198c authored by Janosch Frank's avatar Janosch Frank Committed by Christian Borntraeger
Browse files

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: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarFarhan Ali <alifm@linux.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent a3da7b4a

arch/s390/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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 {

arch/s390/kvm/priv.c

+4 −6
Original line number Diff line number Diff line
@@ -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;

}