Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix ID register initialization for non-protected pKVM guests In protected mode, the hypervisor maintains a separate instance of the `kvm` structure for each VM. For non-protected VMs, this structure is initialized from the host's `kvm` state. Currently, `pkvm_init_features_from_host()` copies the `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the underlying `id_regs` data being initialized. This results in the hypervisor seeing the flag as set while the ID registers remain zeroed. Consequently, `kvm_has_feat()` checks at EL2 fail (return 0) for non-protected VMs. This breaks logic that relies on feature detection, such as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain system registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not saved/restored during the world switch, which could lead to state corruption. Fix this by explicitly copying the ID registers from the host `kvm` to the hypervisor `kvm` for non-protected VMs during initialization, since we trust the host with its non-protected guests' features. Also ensure `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in `pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly initialize them and set the flag once done.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 41d6028e28bd474298ff10409c292ec46cf43a90 before bce3847f7c51b86332bf2e554c9e80ca3820f16c; affected 41d6028e28bd474298ff10409c292ec46cf43a90 before 858620655c1fbff05997e162fc7d83a3293d5142; affected 41d6028e28bd474298ff10409c292ec46cf43a90 before 7e7c2cf0024d89443a7af52e09e47b1fe634ab17 |
| Linux / Linux | affected 6.14; unaffected 0 before 6.14; unaffected 6.18.17 through 6.18.*; unaffected 6.19.7 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.