KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

Overview

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

KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

pkvm_vcpu_init_sve() clamps only the upper bound of the host-provided sve_max_vl, so an invalid vector length reaches sve_state_size_from_vl() and the WARN_ON() there, which is fatal at EL2. The existing !sve_state_size test rejects such a length, but only after the macro has run.

Check sve_vl_valid() before deriving the state size. A valid length cannot yield a zero size, so the !sve_state_size test goes with it.

Affected

• Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 < faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc
• Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 < bae3e4493046de4fefa15f809d9b8dc114e84a3d
• Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 < 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9
• Linux 6.16

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.