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3c6e099fa1
When bit 3 (corresponding to CR0.TS) of the VMCS12 cr0_guest_host_mask field is clear, the VMCS12 guest_cr0 field does not necessarily hold the current value of the L2 CR0.TS bit, so the code that checked for L2's CR0.TS bit being set was incorrect. Moreover, I'm not sure that the CR0.TS check was adequate. (What if L2's CR0.EM was set, for instance?) Fortunately, lazy FPU has gone away, so L0 has lost all interest in intercepting #NM exceptions. See commitbd7e5b0899("KVM: x86: remove code for lazy FPU handling"). Therefore, there is no longer any question of which hypervisor gets first dibs. The #NM VM-exit should always be reflected to L1. (Note that the corresponding bit must be set in the VMCS12 exception_bitmap field for there to be an #NM VM-exit at all.) Fixes:ccf9844e5d("kvm, vmx: Really fix lazy FPU on nested guest") Reported-by: Abhiroop Dabral <adabral@paloaltonetworks.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Tested-by: Abhiroop Dabral <adabral@paloaltonetworks.com> Reviewed-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.