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Move the is_shadow_present_pte() check out of spte_has_volatile_bits() and into its callers. Well, caller, since only one of its two callers doesn't already do the shadow-present check. Opportunistically move the helper to spte.c/h so that it can be used by the TDP MMU, which is also the primary motivation for the shadow-present change. Unlike the legacy MMU, the TDP MMU uses a single path for clear leaf and non-leaf SPTEs, and to avoid unnecessary atomic updates, the TDP MMU will need to check is_last_spte() prior to calling spte_has_volatile_bits(), and calling is_last_spte() without first calling is_shadow_present_spte() is at best odd, and at worst a violation of KVM's loosely defines SPTE rules. Note, mmu_spte_clear_track_bits() could likely skip the write entirely for SPTEs that are not shadow-present. Leave that cleanup for a future patch to avoid introducing a functional change, and because the shadow-present check can likely be moved further up the stack, e.g. drop_large_spte() appears to be the only path that doesn't already explicitly check for a shadow-present SPTE. No functional change intended. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220423034752.1161007-3-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.