Kernel: KVM: export MSR_IA32_TSX_CTRL to guest - incomplete fix for TAA (CVE-2019-11135)

A flaw was found in the fix for CVE-2019-11135, 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 TAANO=0, but is not affected by the MDS issue MDSNO=1, the guest was to...