linux-kernel - [PATCH v4 05/13] KVM: x86/mmu: Drop access tracking checks when clearing TDP MMU dirty bits

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230321220021.2119033-6-seanjc@google.com>
Date:   Tue, 21 Mar 2023 15:00:13 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Vipin Sharma <vipinsh@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH v4 05/13] KVM: x86/mmu: Drop access tracking checks when
 clearing TDP MMU dirty bits

From: Vipin Sharma <vipinsh@...gle.com>

Drop the unnecessary call to handle access-tracking changes when clearing
the dirty status of TDP MMU SPTEs.  Neither the Dirty bit nor the Writable
bit has any impact on the accessed state of a page, i.e. clearing only
the aforementioned bits doesn't make an accessed SPTE suddently not
accessed.

Signed-off-by: Vipin Sharma <vipinsh@...gle.com>
[sean: split to separate patch, write changelog]
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index a70cc1dae18a..950c5d23ecee 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1691,8 +1691,6 @@ static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root,
 
 		__handle_changed_spte(kvm, iter.as_id, iter.gfn, iter.old_spte,
 				      iter.old_spte & ~dbit, iter.level, false);
-		handle_changed_spte_acc_track(iter.old_spte, iter.old_spte & ~dbit,
-					      iter.level);
 	}
 
 	rcu_read_unlock();
-- 
2.40.0.rc2.332.ga46443480c-goog