In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: arm64: Remove VM-wide VNCR mapping counter<\/p>\n
The global VNCR mapping counter is used to decide whether an L1
\nprovided VNCR page is mapped in L0 on any CPU at the point of
\ndealing with a TLB invalidation. It is incremented when a mapping
\nis made in the fixmap, and decremented when unmapped.<\/p>\n
As it turns out, this tracking has several flaws:<\/p>\n
– we are trying to invalidate TLBs, and the mapping is only an
\n opportunistic consequence of the TLB. Checking this counter to
\n decide whether a TLB needs to be invalidated may result in missed
\n invalidations.<\/p>\n
– an L1 vcpu invalidating its own TLB (a very likely case) will not
\n succeed in invalidating the VNCR pseudo TLB because that page is
\n not mapped in L0 at this stage.<\/p>\n
Given that this tracking fails at delivering the minimum guarantees
\nthat are required and is only a performance optimisation, remove it
\ncompletely.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: arm64: Remove VM-wide VNCR mapping counter<\/p>\n
The global VNCR mapping counter is used to decide whether an L1
\nprovided VNCR page<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24602","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24602","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=24602"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24602"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24602"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}