Commit 175f2f5b authored by Jean-Philippe Brucker's avatar Jean-Philippe Brucker Committed by Christian Borntraeger
Browse files

KVM: s390: Check kvm pointer when testing KVM_CAP_S390_HPAGE_1M 



KVM allows issuing the KVM_CHECK_EXTENSION ioctl either on the /dev/kvm
fd or the VM fd. In the first case, kvm_vm_ioctl_check_extension() is
called with kvm==NULL. Ensure we don't dereference the pointer in that
case.

Fixes: 40ebdb8e ("KVM: s390: Make huge pages unavailable in ucontrol VMs")
Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
Message-ID: <20240419160723.320910-2-jean-philippe@linaro.org>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
parent 16c20208

arch/s390/kvm/kvm-s390.c

+1 −1
Original line number Diff line number Diff line
@@ -587,7 +587,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) 
		break;

	case KVM_CAP_S390_HPAGE_1M:

		r = 0;

		if (hpage && !kvm_is_ucontrol(kvm))

		if (hpage && !(kvm && kvm_is_ucontrol(kvm)))

			r = 1;

		break;

	case KVM_CAP_S390_MEM_OP: