CVE-2026-64555

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

KVM: arm64: nv: Fix SPSREL2 restore in kvmhyphandlemops()

kvmhyphandlemops() resets the single-step state machine as part of rewinding state for a MOPS exception by modifying vcpucpsr() and writing the result directly into hardware.

In the case of nested virtualization, vcpu_cpsr() is a synthetic value such that the rest of KVM can deal with vEL2 cleanly. That means the value requires translation before being written into hardware, which is unfortunately missing from the MOPS handler.

Fix it by directly modifying SPSR_EL2 and avoiding the synthetic state altogether, which will be resynchronized on the next 'full' exit back to KVM.