The prepare_vmcs02 function in arch/x86/kvm/vmx.c in the Linux kernel through 4.13.3 does not ensure that the "CR8-load exiting" and "CR8-store exiting" L0 vmcs02 controls exist in cases where L1 omits the "use TPR shadow" vmcs12 control, which allows KVM L2 guest OS users to obtain read and write access to the hardware CR8 register.
The prepare_vmcs02 function in arch/x86/kvm/vmx.c in the Linux kernel through 4.13.3 does not ensure that the "CR8-load exiting" and "CR8-store exiting" L0 vmcs02 controls exist in cases where L1 omits the "use TPR shadow" vmcs12 control, which allows KVM L2 guest OS users to obtain read and write access to the hardware CR8 register.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=51aa68e7d57e3217192d88ce90fd5b8ef29ec94f https://bugzilla.redhat.com/show_bug.cgi?id=1491224
Fixed in: - v4.14-rc1 by 51aa68e7d57e3217192d88ce90fd5b8ef29ec94f - v3.18.73 by 6ad74630c016ef823f2720671ee4db641d35fd2c - v4.4.90 by 21a638c5efd6ec7a10441bfb94e15e5288920f07 - v4.9.53 by 86ef97b2dfd504fbc65f6b244a422db0c1b15797 - v4.13.5 by 27920625f93e59b2b24bdadf946ae4b61f885f40 - v3.2.94 by 7999f7fc5b2ca4c0b2a96b7fb3dfa4e30274da27 - v3.16.49 by 423a7a81efb8da25dbbcfe7a33bd8bfdce34150b
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