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Commit aca411a4 authored by Julius Niedworok's avatar Julius Niedworok Committed by Christian Borntraeger
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KVM: s390: reset KVM_REQ_MMU_RELOAD if mapping the prefix failed 



When triggering KVM_RUN without a user memory region being mapped
(KVM_SET_USER_MEMORY_REGION) a validity intercept occurs. This could
happen, if the user memory region was not mapped initially or if it
was unmapped after the vcpu is initialized. The function
kvm_s390_handle_requests checks for the KVM_REQ_MMU_RELOAD bit. The
check function always clears this bit. If gmap_mprotect_notify
returns an error code, the mapping failed, but the KVM_REQ_MMU_RELOAD
was not set anymore. So the next time kvm_s390_handle_requests is
called, the execution would fall trough the check for
KVM_REQ_MMU_RELOAD. The bit needs to be resetted, if
gmap_mprotect_notify returns an error code. Resetting the bit with
kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu) fixes the bug.

Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarJulius Niedworok <jniedwor@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 75a4615c

arch/s390/kvm/kvm-s390.c

+3 −1
Original line number Diff line number Diff line
@@ -2362,8 +2362,10 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu) 
		rc = gmap_mprotect_notify(vcpu->arch.gmap,

					  kvm_s390_get_prefix(vcpu),

					  PAGE_SIZE * 2, PROT_WRITE);

		if (rc)

		if (rc) {

			kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);

			return rc;

		}

		goto retry;

	}