Description
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state Explicitly flush caches after intra-host migration before clearing "SEV active" on the source VM, as doing cache maintenance afterwards creates a tiny window where memory reclaim could return memory to the host without performing a cache flush, e.g. as pointed out by Sashiko: CPU1 in sev_migrate_from(): src->active = false; CPU2 running concurrent unmap: Since active is false, the automatic cache flush in sev_guest_memory_reclaimed is skipped. The host frees and reallocates the page. CPU1 in sev_migrate_from(): sev_writeback_caches(src_kvm); Executes a hardware cache flush (wbnoinvd), which writes the guest's old dirty ciphertext over the new page owner's data.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
37dfb676fafd1eef36fe0bb649607afbb0d5521b to < 8b7d4f68fef96cebe0b6dbb6e5607772337f7369affectedd4cc2dff12116a700add601c0262132cc26e1b2c to < de83ff6a4d8f3618473bedb3c4400020c22e8a8aaffected93de2a6a4b91b72607136dd656edf03fb399d27f to < 973ea70393e885e540f714904e51bc6cac80e3d7affected
Linux Linux
Default version status: unaffected
6.18.55 to < 6.18.56affected7.2.9 to < 7.2.10affected