[PATCH 2/3] [RFC V3] KVM: X86: Adding arbitrary data pointer in kvm memslot itterator functions

From: Ahmed Abd El Mawgood <ahmedsoliman0x666@gmail.com>
To: kvm@vger.kernel.org,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	virtualization@lists.linux-foundation.org,
	linux-doc@vger.kernel.org, x86@kernel.org
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Kees Cook <keescook@chromium.org>, nathan Corbet <corbet@lwn.net>,
	David Vrabel <david.vrabel@nutanix.com>,
	rkrcmar@redhat.com, Boris Lukashev <blukashev@sempervictus.com>,
	Ingo Molnar <mingo@redhat.com>,
	nigel.edwards@hpe.com, hpa@zytor.com,
	Paolo Bonzini <pbonzini@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Rik van Riel <riel@surriel.com>
Subject: [PATCH 2/3] [RFC V3] KVM: X86: Adding arbitrary data pointer in kvm memslot itterator functions
Date: Thu, 19 Jul 2018 23:38:01 +0200	[thread overview]
Message-ID: <20180719213802.17161-3-ahmedsoliman0x666__7896.37080529264$1532036405$gmane$org@gmail.com> (raw)
In-Reply-To: <20180719213802.17161-1-ahmedsoliman0x666@gmail.com>

This will help sharing data into the slot_level_handler callback. In my
case I need to a share a counter for the pages traversed to use it in some
bitmap. Being able to send arbitrary memory pointer into the
slot_level_handler callback made it easy.

Signed-off-by: Ahmed Abd El Mawgood <ahmedsoliman0x666@gmail.com>
---
 arch/x86/kvm/mmu.c | 65 +++++++++++++++++++++++++++++++-----------------------
 1 file changed, 37 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d594690d8b95..77661530b2c4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1418,7 +1418,7 @@ static bool spte_write_protect(u64 *sptep, bool pt_protect)
 
 static bool __rmap_write_protect(struct kvm *kvm,
 				 struct kvm_rmap_head *rmap_head,
-				 bool pt_protect)
+				 bool pt_protect, void *data)
 {
 	u64 *sptep;
 	struct rmap_iterator iter;
@@ -1457,7 +1457,8 @@ static bool wrprot_ad_disabled_spte(u64 *sptep)
  *	- W bit on ad-disabled SPTEs.
  * Returns true iff any D or W bits were cleared.
  */
-static bool __rmap_clear_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
+static bool __rmap_clear_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+				void *data)
 {
 	u64 *sptep;
 	struct rmap_iterator iter;
@@ -1483,7 +1484,8 @@ static bool spte_set_dirty(u64 *sptep)
 	return mmu_spte_update(sptep, spte);
 }
 
-static bool __rmap_set_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
+static bool __rmap_set_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+				void *data)
 {
 	u64 *sptep;
 	struct rmap_iterator iter;
@@ -1515,7 +1517,7 @@ static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
 	while (mask) {
 		rmap_head = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
 					  PT_PAGE_TABLE_LEVEL, slot);
-		__rmap_write_protect(kvm, rmap_head, false);
+		__rmap_write_protect(kvm, rmap_head, false, NULL);
 
 		/* clear the first set bit */
 		mask &= mask - 1;
@@ -1541,7 +1543,7 @@ void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
 	while (mask) {
 		rmap_head = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
 					  PT_PAGE_TABLE_LEVEL, slot);
-		__rmap_clear_dirty(kvm, rmap_head);
+		__rmap_clear_dirty(kvm, rmap_head, NULL);
 
 		/* clear the first set bit */
 		mask &= mask - 1;
@@ -1594,7 +1596,8 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
 
 	for (i = PT_PAGE_TABLE_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
 		rmap_head = __gfn_to_rmap(gfn, i, slot);
-		write_protected |= __rmap_write_protect(kvm, rmap_head, true);
+		write_protected |= __rmap_write_protect(kvm, rmap_head, true,
+				NULL);
 	}
 
 	return write_protected;
@@ -1608,7 +1611,8 @@ static bool rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
 	return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn);
 }
 
-static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
+static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+		void *data)
 {
 	u64 *sptep;
 	struct rmap_iterator iter;
@@ -1628,7 +1632,7 @@ static int kvm_unmap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
 			   struct kvm_memory_slot *slot, gfn_t gfn, int level,
 			   unsigned long data)
 {
-	return kvm_zap_rmapp(kvm, rmap_head);
+	return kvm_zap_rmapp(kvm, rmap_head, NULL);
 }
 
 static int kvm_set_pte_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
@@ -5086,13 +5090,15 @@ void kvm_mmu_uninit_vm(struct kvm *kvm)
 }
 
 /* The return value indicates if tlb flush on all vcpus is needed. */
-typedef bool (*slot_level_handler) (struct kvm *kvm, struct kvm_rmap_head *rmap_head);
+typedef bool (*slot_level_handler) (struct kvm *kvm,
+		struct kvm_rmap_head *rmap_head, void *data);
 
 /* The caller should hold mmu-lock before calling this function. */
 static __always_inline bool
 slot_handle_level_range(struct kvm *kvm, struct kvm_memory_slot *memslot,
 			slot_level_handler fn, int start_level, int end_level,
-			gfn_t start_gfn, gfn_t end_gfn, bool lock_flush_tlb)
+			gfn_t start_gfn, gfn_t end_gfn, bool lock_flush_tlb,
+			void *data)
 {
 	struct slot_rmap_walk_iterator iterator;
 	bool flush = false;
@@ -5100,7 +5106,7 @@ slot_handle_level_range(struct kvm *kvm, struct kvm_memory_slot *memslot,
 	for_each_slot_rmap_range(memslot, start_level, end_level, start_gfn,
 			end_gfn, &iterator) {
 		if (iterator.rmap)
-			flush |= fn(kvm, iterator.rmap);
+			flush |= fn(kvm, iterator.rmap, data);
 
 		if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
 			if (flush && lock_flush_tlb) {
@@ -5122,36 +5128,36 @@ slot_handle_level_range(struct kvm *kvm, struct kvm_memory_slot *memslot,
 static __always_inline bool
 slot_handle_level(struct kvm *kvm, struct kvm_memory_slot *memslot,
 		  slot_level_handler fn, int start_level, int end_level,
-		  bool lock_flush_tlb)
+		  bool lock_flush_tlb, void *data)
 {
 	return slot_handle_level_range(kvm, memslot, fn, start_level,
 			end_level, memslot->base_gfn,
 			memslot->base_gfn + memslot->npages - 1,
-			lock_flush_tlb);
+			lock_flush_tlb, data);
 }
 
 static __always_inline bool
 slot_handle_all_level(struct kvm *kvm, struct kvm_memory_slot *memslot,
-		      slot_level_handler fn, bool lock_flush_tlb)
+		      slot_level_handler fn, bool lock_flush_tlb, void *data)
 {
 	return slot_handle_level(kvm, memslot, fn, PT_PAGE_TABLE_LEVEL,
-				 PT_MAX_HUGEPAGE_LEVEL, lock_flush_tlb);
+				 PT_MAX_HUGEPAGE_LEVEL, lock_flush_tlb, data);
 }
 
 static __always_inline bool
 slot_handle_large_level(struct kvm *kvm, struct kvm_memory_slot *memslot,
-			slot_level_handler fn, bool lock_flush_tlb)
+			slot_level_handler fn, bool lock_flush_tlb, void *data)
 {
 	return slot_handle_level(kvm, memslot, fn, PT_PAGE_TABLE_LEVEL + 1,
-				 PT_MAX_HUGEPAGE_LEVEL, lock_flush_tlb);
+				 PT_MAX_HUGEPAGE_LEVEL, lock_flush_tlb, data);
 }
 
 static __always_inline bool
 slot_handle_leaf(struct kvm *kvm, struct kvm_memory_slot *memslot,
-		 slot_level_handler fn, bool lock_flush_tlb)
+		 slot_level_handler fn, bool lock_flush_tlb, void *data)
 {
 	return slot_handle_level(kvm, memslot, fn, PT_PAGE_TABLE_LEVEL,
-				 PT_PAGE_TABLE_LEVEL, lock_flush_tlb);
+				 PT_PAGE_TABLE_LEVEL, lock_flush_tlb, data);
 }
 
 void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
@@ -5173,7 +5179,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 
 			slot_handle_level_range(kvm, memslot, kvm_zap_rmapp,
 						PT_PAGE_TABLE_LEVEL, PT_MAX_HUGEPAGE_LEVEL,
-						start, end - 1, true);
+						start, end - 1, true, NULL);
 		}
 	}
 
@@ -5181,9 +5187,10 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 }
 
 static bool slot_rmap_write_protect(struct kvm *kvm,
-				    struct kvm_rmap_head *rmap_head)
+				    struct kvm_rmap_head *rmap_head,
+				    void *data)
 {
-	return __rmap_write_protect(kvm, rmap_head, false);
+	return __rmap_write_protect(kvm, rmap_head, false, data);
 }
 
 void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
@@ -5193,7 +5200,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
 
 	spin_lock(&kvm->mmu_lock);
 	flush = slot_handle_all_level(kvm, memslot, slot_rmap_write_protect,
-				      false);
+				      false, NULL);
 	spin_unlock(&kvm->mmu_lock);
 
 	/*
@@ -5219,7 +5226,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
 }
 
 static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
-					 struct kvm_rmap_head *rmap_head)
+					 struct kvm_rmap_head *rmap_head,
+					 void *data)
 {
 	u64 *sptep;
 	struct rmap_iterator iter;
@@ -5257,7 +5265,7 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
 	/* FIXME: const-ify all uses of struct kvm_memory_slot.  */
 	spin_lock(&kvm->mmu_lock);
 	slot_handle_leaf(kvm, (struct kvm_memory_slot *)memslot,
-			 kvm_mmu_zap_collapsible_spte, true);
+			 kvm_mmu_zap_collapsible_spte, true, NULL);
 	spin_unlock(&kvm->mmu_lock);
 }
 
@@ -5267,7 +5275,7 @@ void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
 	bool flush;
 
 	spin_lock(&kvm->mmu_lock);
-	flush = slot_handle_leaf(kvm, memslot, __rmap_clear_dirty, false);
+	flush = slot_handle_leaf(kvm, memslot, __rmap_clear_dirty, false, NULL);
 	spin_unlock(&kvm->mmu_lock);
 
 	lockdep_assert_held(&kvm->slots_lock);
@@ -5290,7 +5298,7 @@ void kvm_mmu_slot_largepage_remove_write_access(struct kvm *kvm,
 
 	spin_lock(&kvm->mmu_lock);
 	flush = slot_handle_large_level(kvm, memslot, slot_rmap_write_protect,
-					false);
+					false, NULL);
 	spin_unlock(&kvm->mmu_lock);
 
 	/* see kvm_mmu_slot_remove_write_access */
@@ -5307,7 +5315,8 @@ void kvm_mmu_slot_set_dirty(struct kvm *kvm,
 	bool flush;
 
 	spin_lock(&kvm->mmu_lock);
-	flush = slot_handle_all_level(kvm, memslot, __rmap_set_dirty, false);
+	flush = slot_handle_all_level(kvm, memslot, __rmap_set_dirty, false,
+			NULL);
 	spin_unlock(&kvm->mmu_lock);
 
 	lockdep_assert_held(&kvm->slots_lock);
-- 
2.16.4
