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Commit 3edbcff9 authored by Carsten Otte's avatar Carsten Otte Committed by Avi Kivity
Browse files

KVM: s390: Sanity check on validity intercept 



This patch adds a sanity check for the content of the guest
prefix register content before faulting in the cpu lowcore
that it refers to. The guest might end up in an endless loop
where SIE complains about missing lowcore with incorrect
content of the prefix register without this fix.

Reported-by: default avatarMijo Safradin <mijo@linux.vnet.ibm.com>
Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
Signed-off-by: default avatarChristian Ehrhardt <ehrhardt@de.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent abf4a71e

arch/s390/kvm/intercept.c

+18 −10
Original line number Diff line number Diff line
@@ -154,17 +154,25 @@ static int handle_stop(struct kvm_vcpu *vcpu) 
static int handle_validity(struct kvm_vcpu *vcpu)

{

	int viwhy = vcpu->arch.sie_block->ipb >> 16;

	int rc;



	vcpu->stat.exit_validity++;

	if (viwhy == 0x37) {

		fault_in_pages_writeable((char __user *)

	if ((viwhy == 0x37) && (vcpu->arch.sie_block->prefix

		<= vcpu->kvm->arch.guest_memsize - 2*PAGE_SIZE)){

		rc = fault_in_pages_writeable((char __user *)

			 vcpu->kvm->arch.guest_origin +

			 vcpu->arch.sie_block->prefix,

					 PAGE_SIZE);

		return 0;

	}

			 2*PAGE_SIZE);

		if (rc)

			/* user will receive sigsegv, exit to user */

			rc = -ENOTSUPP;

	} else

		rc = -ENOTSUPP;



	if (rc)

		VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",

			   viwhy);

	return -ENOTSUPP;

	return rc;

}



static int handle_instruction(struct kvm_vcpu *vcpu)