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ec283cb1dc
The ept_ad field is used during page walk to determine if the guest PTEs have accessed and dirty bits. In the MMU role, the ad_disabled bit represents whether the *shadow* PTEs have the bits, so it would be incorrect to replace PT_HAVE_ACCESSED_DIRTY with just !mmu->mmu_role.base.ad_disabled. However, the similar field in the CPU mode, ad_disabled, is initialized correctly: to the opposite value of ept_ad for shadow EPT, and zero for non-EPT guest paging modes (which always have A/D bits). It is therefore possible to compute PT_HAVE_ACCESSED_DIRTY from the CPU mode, like other page-format fields; it just has to be inverted to account for the different polarity. In fact, now that the CPU mode is distinct from the MMU roles, it would even be possible to remove PT_HAVE_ACCESSED_DIRTY macro altogether, and use !mmu->cpu_role.base.ad_disabled instead. I am not doing this because the macro has a small effect in terms of dead code elimination: text data bss dec hex 103544 16665 112 120321 1d601 # as of this patch 103746 16665 112 120523 1d6cb # without PT_HAVE_ACCESSED_DIRTY Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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| .. | ||
| mmu_internal.h | ||
| mmu.c | ||
| mmutrace.h | ||
| page_track.c | ||
| paging_tmpl.h | ||
| paging.h | ||
| spte.c | ||
| spte.h | ||
| tdp_iter.c | ||
| tdp_iter.h | ||
| tdp_mmu.c | ||
| tdp_mmu.h | ||