KVM: x86/mmu: Don't mark unused faultin pages as accessed

KVM: x86/mmu: Don't mark unused faultin pages as accessed

When finishing guest page faults, don't mark pages as accessed if KVM
is resuming the guest _without_ installing a mapping, i.e. if the page
isn't being used.  While it's possible that marking the page accessed
could avoid minor thrashing due to reclaiming a page that the guest is
about to access, it's far more likely that the gfn=>pfn mapping was
was invalidated, e.g. due a memslot change, or because the corresponding
VMA is being modified.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-49-seanjc@google.com>