Commit ad6787df authored by Ben Gardon's avatar Ben Gardon Committed by Yu Zhang
Browse files

KVM: x86/mmu: Skip no-op changes in TDP MMU functions 

mainline inclusion
from mainline-v5.12-rc1
commit 0f99ee2c
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I7S3VQ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0f99ee2c7a58fc281c084d3acc0f0013bec7ec5a



----------------------------------------------------------------------

Skip setting SPTEs if no change is expected.

Reviewed-by: default avatarPeter Feiner <pfeiner@google.com>
Signed-off-by: default avatarBen Gardon <bgardon@google.com>

Message-Id: <20210202185734.1680553-16-bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarYu Zhang <yu.c.zhang@linux.intel.com>
parent fe26b7fa

arch/x86/kvm/mmu/tdp_mmu.c

+4 −2
Original line number Diff line number Diff line
@@ -891,7 +891,8 @@ static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, 
			continue;



		if (!is_shadow_present_pte(iter.old_spte) ||

		    !is_last_spte(iter.old_spte, iter.level))

		    !is_last_spte(iter.old_spte, iter.level) ||

		    !(iter.old_spte & PT_WRITABLE_MASK))

			continue;



		new_spte = iter.old_spte & ~PT_WRITABLE_MASK;
@@ -1071,7 +1072,8 @@ static bool set_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, 
		if (tdp_mmu_iter_cond_resched(kvm, &iter, false))

			continue;



		if (!is_shadow_present_pte(iter.old_spte))

		if (!is_shadow_present_pte(iter.old_spte) ||

		    iter.old_spte & shadow_dirty_mask)

			continue;



		new_spte = iter.old_spte | shadow_dirty_mask;