linux-kernel - [PATCH v2 16/30] KVM: x86/mmu: Refactor low-level TDP MMU set SPTE helper to take raw vals

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Message-Id: <20211223222318.1039223-17-seanjc@google.com>
Date:   Thu, 23 Dec 2021 22:23:04 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ben Gardon <bgardon@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Mingwei Zhang <mizhang@...gle.com>
Subject: [PATCH v2 16/30] KVM: x86/mmu: Refactor low-level TDP MMU set SPTE
 helper to take raw vals

Refactor __tdp_mmu_set_spte() to work with raw values instead of a
tdp_iter objects so that a future patch can modify SPTEs without doing a
walk, and without having to synthesize a tdp_iter.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Reviewed-by: Ben Gardon <bgardon@...gle.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 51 +++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index e2d217cbeca3..61596b4a8121 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -611,9 +611,13 @@ static inline bool tdp_mmu_zap_spte_atomic(struct kvm *kvm,
 
 /*
  * __tdp_mmu_set_spte - Set a TDP MMU SPTE and handle the associated bookkeeping
- * @kvm: kvm instance
- * @iter: a tdp_iter instance currently on the SPTE that should be set
- * @new_spte: The value the SPTE should be set to
+ * @kvm:	      KVM instance
+ * @as_id:	      Address space ID, i.e. regular vs. SMM
+ * @sptep:	      Pointer to the SPTE
+ * @old_spte:	      The current value of the SPTE
+ * @new_spte:	      The new value that will be set for the SPTE
+ * @gfn:	      The base GFN that was (or will be) mapped by the SPTE
+ * @level:	      The level _containing_ the SPTE (its parent PT's level)
  * @record_acc_track: Notify the MM subsystem of changes to the accessed state
  *		      of the page. Should be set unless handling an MMU
  *		      notifier for access tracking. Leaving record_acc_track
@@ -625,12 +629,10 @@ static inline bool tdp_mmu_zap_spte_atomic(struct kvm *kvm,
  *		      Leaving record_dirty_log unset in that case prevents page
  *		      writes from being double counted.
  */
-static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
-				      u64 new_spte, bool record_acc_track,
-				      bool record_dirty_log)
+static void __tdp_mmu_set_spte(struct kvm *kvm, int as_id, tdp_ptep_t sptep,
+			       u64 old_spte, u64 new_spte, gfn_t gfn, int level,
+			       bool record_acc_track, bool record_dirty_log)
 {
-	WARN_ON_ONCE(iter->yielded);
-
 	lockdep_assert_held_write(&kvm->mmu_lock);
 
 	/*
@@ -640,39 +642,48 @@ static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
 	 * should be used. If operating under the MMU lock in write mode, the
 	 * use of the removed SPTE should not be necessary.
 	 */
-	WARN_ON(is_removed_spte(iter->old_spte) || is_removed_spte(new_spte));
+	WARN_ON(is_removed_spte(old_spte) || is_removed_spte(new_spte));
 
-	kvm_tdp_mmu_write_spte(iter->sptep, new_spte);
+	kvm_tdp_mmu_write_spte(sptep, new_spte);
+
+	__handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level, false);
 
-	__handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
-			      new_spte, iter->level, false);
 	if (record_acc_track)
-		handle_changed_spte_acc_track(iter->old_spte, new_spte,
-					      iter->level);
+		handle_changed_spte_acc_track(old_spte, new_spte, level);
 	if (record_dirty_log)
-		handle_changed_spte_dirty_log(kvm, iter->as_id, iter->gfn,
-					      iter->old_spte, new_spte,
-					      iter->level);
+		handle_changed_spte_dirty_log(kvm, as_id, gfn, old_spte,
+					      new_spte, level);
+}
+
+static inline void _tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
+				     u64 new_spte, bool record_acc_track,
+				     bool record_dirty_log)
+{
+	WARN_ON_ONCE(iter->yielded);
+
+	__tdp_mmu_set_spte(kvm, iter->as_id, iter->sptep, iter->old_spte,
+			   new_spte, iter->gfn, iter->level,
+			   record_acc_track, record_dirty_log);
 }
 
 static inline void tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
 				    u64 new_spte)
 {
-	__tdp_mmu_set_spte(kvm, iter, new_spte, true, true);
+	_tdp_mmu_set_spte(kvm, iter, new_spte, true, true);
 }
 
 static inline void tdp_mmu_set_spte_no_acc_track(struct kvm *kvm,
 						 struct tdp_iter *iter,
 						 u64 new_spte)
 {
-	__tdp_mmu_set_spte(kvm, iter, new_spte, false, true);
+	_tdp_mmu_set_spte(kvm, iter, new_spte, false, true);
 }
 
 static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
 						 struct tdp_iter *iter,
 						 u64 new_spte)
 {
-	__tdp_mmu_set_spte(kvm, iter, new_spte, true, false);
+	_tdp_mmu_set_spte(kvm, iter, new_spte, true, false);
 }
 
 #define tdp_root_for_each_pte(_iter, _root, _start, _end) \
-- 
2.34.1.448.ga2b2bfdf31-goog