Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: nv: Re-translate VNCR before injecting abort
KVM faults in the VNCR page with FOLL_WRITE whenever the guest aborts for a write, similar to how a regular stage-2 mapping is handled. It is entirely possible that the guest reads from the VNCR before writing to it, in which case the PFN could only be read-only.
Invalidate the VNCR TLB and re-fetch the translation upon taking a VNCR abort, allowing the host mapping to be faulted in for write the second time around. Interestingly enough, this also satisfies the ordering requirements of FEAT_ETS2/3 between descriptor updates and MMU faults.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0