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20f632bd00
Grab all CR0/CR4 MMU role bits from current vCPU state when initializing
a non-nested shadow MMU. Extract the masks from kvm_post_set_cr{0,4}(),
as the CR0/CR4 update masks must exactly match the mmu_role bits, with
one exception (see below). The "full" CR0/CR4 will be used by future
commits to initialize the MMU and its role, as opposed to the current
approach of pulling everything from vCPU, which is incorrect for certain
flows, e.g. nested NPT.
CR4.LA57 is an exception, as it can be toggled on VM-Exit (for L1's MMU)
but can't be toggled via MOV CR4 while long mode is active. I.e. LA57
needs to be in the mmu_role, but technically doesn't need to be checked
by kvm_post_set_cr4(). However, the extra check is completely benign as
the hardware restrictions simply mean LA57 will never be _the_ cause of
a MMU reset during MOV CR4.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622175739.3610207-18-seanjc@google.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.
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.