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commit112022bdb5upstream Mark NX as being used for all non-nested shadow MMUs, as KVM will set the NX bit for huge SPTEs if the iTLB mutli-hit mitigation is enabled. Checking the mitigation itself is not sufficient as it can be toggled on at any time and KVM doesn't reset MMU contexts when that happens. KVM could reset the contexts, but that would require purging all SPTEs in all MMUs, for no real benefit. And, KVM already forces EFER.NX=1 when TDP is disabled (for WP=0, SMEP=1, NX=0), so technically NX is never reserved for shadow MMUs. Fixes:b8e8c8303f("kvm: mmu: ITLB_MULTIHIT mitigation") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [sudip: use old path and adjust context] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.