In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state<\/p>\n
Explicitly flush caches after intra-host migration before clearing “SEV
\nactive” on the source VM, as doing cache maintenance afterwards creates a
\ntiny window where memory reclaim could return memory to the host without
\nperforming a cache flush, e.g. as pointed out by Sashiko:<\/p>\n
CPU1 in sev_migrate_from():
\n src->active = false;<\/p>\n
CPU2 running concurrent unmap:
\n Since active is false, the automatic cache flush in
\n sev_guest_memory_reclaimed is skipped.
\n The host frees and reallocates the page.<\/p>\n
CPU1 in sev_migrate_from():
\n sev_writeback_caches(src_kvm);
\n Executes a hardware cache flush (wbnoinvd), which writes the guest’s old
\n dirty ciphertext over the new page owner’s data.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state<\/p>\n
Explicitly flush caches after intra-host migration bef<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41190","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41190","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=41190"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41190"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41190"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}