KVM: s390: vsie: speed up VCPU external calls (b917ae57) · Commits · e / devices / android_kernel_xiaomi_nabu

Whenever a SIGP external call is injected via the SIGP external call interpretation facility, the VCPU is not kicked. When a VCPU is currently in the VSIE, the external call might not be processed immediately. Therefore we have to provoke partial execution exceptions, which leads to a kick of the VCPU and therefore also kick out of VSIE. This is done by simulating the WAIT state. This bit has no other side effects. Acked-by:

Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by:

David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by:

Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/kvm/vsie.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -844,6 +844,11 @@ static void register_shadow_scb(struct kvm_vcpu *vcpu,
	struct vsie_page *vsie_page)		struct vsie_page *vsie_page)
	{		{
	WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);		WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
			/*
			* External calls have to lead to a kick of the vcpu and
			* therefore the vsie -> Simulate Wait state.
			*/
			atomic_or(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
	}		}

	/*		/*
	@@ -851,6 +856,7 @@ static void register_shadow_scb(struct kvm_vcpu *vcpu,
	*/		*/
	static void unregister_shadow_scb(struct kvm_vcpu *vcpu)		static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
	{		{
			atomic_andnot(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
	WRITE_ONCE(vcpu->arch.vsie_block, NULL);		WRITE_ONCE(vcpu->arch.vsie_block, NULL);
	}		}