CVE-2026-63806 KVM: Replace guest-triggerable BUG_ON() in ioeventfd datamatch with get_unaligned()

In the Linux kernel, the following vulnerability has been resolved: KVM: Replace guest-triggerable BUGON in ioeventfd datamatch with getunaligned Drop a BUGON that has been reachable since it was first added, way back in 2009, and instead use getunaligned to perform potentially-unaligned accesses...