Commit df989238 authored by Christoph Schlameuss's avatar Christoph Schlameuss Committed by Claudio Imbrenda
Browse files

KVM: s390: Reject setting flic pfault attributes on ucontrol VMs 



Prevent null pointer dereference when processing the
KVM_DEV_FLIC_APF_ENABLE and KVM_DEV_FLIC_APF_DISABLE_WAIT ioctls in the
interrupt controller.

Fixes: 3c038e6b ("KVM: async_pf: Async page fault support on s390")
Reported-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: default avatarChristoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: default avatarHariharan Mari <hari55@linux.ibm.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20241216092140.329196-2-schlameuss@linux.ibm.com


Message-ID: <20241216092140.329196-2-schlameuss@linux.ibm.com>
Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
parent 984aaf61

Documentation/virt/kvm/devices/s390_flic.rst

+4 −0
Original line number Diff line number Diff line
@@ -58,11 +58,15 @@ Groups: 
    Enables async page faults for the guest. So in case of a major page fault

    the host is allowed to handle this async and continues the guest.



    -EINVAL is returned when called on the FLIC of a ucontrol VM.



  KVM_DEV_FLIC_APF_DISABLE_WAIT

    Disables async page faults for the guest and waits until already pending

    async page faults are done. This is necessary to trigger a completion interrupt

    for every init interrupt before migrating the interrupt list.



    -EINVAL is returned when called on the FLIC of a ucontrol VM.



  KVM_DEV_FLIC_ADAPTER_REGISTER

    Register an I/O adapter interrupt source. Takes a kvm_s390_io_adapter

    describing the adapter to register::

arch/s390/kvm/interrupt.c

+4 −0
Original line number Diff line number Diff line
@@ -2678,9 +2678,13 @@ static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr) 
		kvm_s390_clear_float_irqs(dev->kvm);

		break;

	case KVM_DEV_FLIC_APF_ENABLE:

		if (kvm_is_ucontrol(dev->kvm))

			return -EINVAL;

		dev->kvm->arch.gmap->pfault_enabled = 1;

		break;

	case KVM_DEV_FLIC_APF_DISABLE_WAIT:

		if (kvm_is_ucontrol(dev->kvm))

			return -EINVAL;

		dev->kvm->arch.gmap->pfault_enabled = 0;

		/*

		 * Make sure no async faults are in transition when