CVE-2026-68454: KVM: s390: pci: Fix handling of AIF enable without AISB

From: Greg Kroah-Hartman <[email protected]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

KVM: s390: pci: Fix handling of AIF enable without AISB

When a guest seeks to register IRQs without a summary bit specified,
ensure that the associated GAITE then stores 0 for the guest AISB
location instead of virt_to_phys(page_address(NULL)).

The Linux kernel CVE team has assigned CVE-2026-68454 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.0 with commit 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and fixed in 6.1.178 with commit f887df91826e72b570c5e9298e66dd929f09edde
	Issue introduced in 6.0 with commit 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and fixed in 6.6.145 with commit 3ef3190e30601b2688bdc64169b938b8d7f42010
	Issue introduced in 6.0 with commit 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and fixed in 6.12.97 with commit d48b9b096d11e31690c0a4988f65f21b64c01b2a
	Issue introduced in 6.0 with commit 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and fixed in 6.18.40 with commit df72596278b0e22dac5ef2881e9221a3a2c4ed11
	Issue introduced in 6.0 with commit 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and fixed in 7.1.5 with commit 124a3769c43713a11a93a821b313e61ad5110cb8
	Issue introduced in 6.0 with commit 3c5a1b6f0a18520a0edd0600fef6f1a8553b8fdc and fixed in 7.2-rc4 with commit 3e3aa6da87d30a0064a17b836685cd43c90a3572

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-68454
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	arch/s390/kvm/pci.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f887df91826e72b570c5e9298e66dd929f09edde
	https://git.kernel.org/stable/c/3ef3190e30601b2688bdc64169b938b8d7f42010
	https://git.kernel.org/stable/c/d48b9b096d11e31690c0a4988f65f21b64c01b2a
	https://git.kernel.org/stable/c/df72596278b0e22dac5ef2881e9221a3a2c4ed11
	https://git.kernel.org/stable/c/124a3769c43713a11a93a821b313e61ad5110cb8
	https://git.kernel.org/stable/c/3e3aa6da87d30a0064a17b836685cd43c90a3572