Xen 安全漏洞

Xen is an open source virtual machine monitor product from the University of Cambridge, UK. The product enables different and incompatible operating systems to run on the same computer and supports runtime migration to ensure uptime and avoid downtime. Xen suffers from a security vulnerability th...

A flaw was found in the fix for CVE-2019-11135 in the Linux upstream kernel versions before 5.5 where the way Intel CPUs handle speculative execution of instructions when a TSX Asynchronous Abort (TAA) error occurs. When a guest is running on a host CPU affected by the TAA flaw (TAA_NO=0) but is not affected by the MDS issue (MDS_NO=1) the guest was to clear the affected buffers by using a VERW instruction mechanism. But when the MDS_NO=1 bit was exported to the guests the guests did not use the VERW mechanism to clear the affected buffers. This issue affects guests running on Cascade Lake CPUs and requires that host has 'TSX' enabled. Confidentiality of data is the highest threat associated with this vulnerability.

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