linux-kernel - [PATCH v2 5/6] KVM: x86/mmu: Introduce helper function to do range-based flushing for given page

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Date:   Wed, 24 Aug 2022 17:29:22 +0800
From:   "Hou Wenlong" <houwenlong.hwl@...group.com>
To:     kvm@...r.kernel.org
Cc:     David Matlack <dmatlack@...gle.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 5/6] KVM: x86/mmu: Introduce helper function to do range-based flushing for given page

Flushing tlb for one page (huge or not) is the main use case, so
introduce a helper function for this common operation to make
the code clear.

Suggested-by: David Matlack <dmatlack@...gle.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@...group.com>
---
 arch/x86/kvm/mmu/mmu.c          | 16 ++++++----------
 arch/x86/kvm/mmu/mmu_internal.h | 10 ++++++++++
 arch/x86/kvm/mmu/tdp_mmu.c      |  6 ++----
 3 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e0b9432b9491..92ca76e11d96 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -268,16 +268,14 @@ static void kvm_flush_remote_tlbs_sptep(struct kvm *kvm, u64 *sptep)
 	struct kvm_mmu_page *sp = sptep_to_sp(sptep);
 	gfn_t gfn = kvm_mmu_page_get_gfn(sp, spte_index(sptep));

-	kvm_flush_remote_tlbs_with_address(kvm, gfn,
-					   KVM_PAGES_PER_HPAGE(sp->role.level));
+	kvm_flush_remote_tlbs_gfn(kvm, gfn, sp->role.level);
 }

 /* Flush all memory mapped by the given direct SP. */
 static void kvm_flush_remote_tlbs_direct_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
 {
 	WARN_ON_ONCE(!sp->role.direct);
-	kvm_flush_remote_tlbs_with_address(kvm, sp->gfn,
-					   KVM_PAGES_PER_HPAGE(sp->role.level + 1));
+	kvm_flush_remote_tlbs_gfn(kvm, sp->gfn, sp->role.level + 1);
 }

 static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
@@ -1449,8 +1447,8 @@ static bool kvm_set_pte_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
 	}

 	if (need_flush && kvm_available_flush_tlb_with_range()) {
-		kvm_flush_remote_tlbs_with_address(kvm, gfn & -KVM_PAGES_PER_HPAGE(level),
-						   KVM_PAGES_PER_HPAGE(level));
+		kvm_flush_remote_tlbs_gfn(kvm, gfn & -KVM_PAGES_PER_HPAGE(level),
+					  level);
 		return false;
 	}

@@ -1618,8 +1616,7 @@ static void __rmap_add(struct kvm *kvm,

 	if (rmap_count > RMAP_RECYCLE_THRESHOLD) {
 		kvm_zap_all_rmap_sptes(kvm, rmap_head);
-		kvm_flush_remote_tlbs_with_address(
-				kvm, gfn, KVM_PAGES_PER_HPAGE(sp->role.level));
+		kvm_flush_remote_tlbs_gfn(kvm, gfn, sp->role.level);
 	}
 }

@@ -2844,8 +2841,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
 	}

 	if (flush)
-		kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn,
-				KVM_PAGES_PER_HPAGE(level));
+		kvm_flush_remote_tlbs_gfn(vcpu->kvm, gfn, level);

 	pgprintk("%s: setting spte %llx\n", __func__, *sptep);

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 582def531d4d..6651c154f2e0 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -163,8 +163,18 @@ void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
 				    struct kvm_memory_slot *slot, u64 gfn,
 				    int min_level);
+
 void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
 					u64 start_gfn, u64 pages);
+
+/* Flush the given page (huge or not) of guest memory. */
+static inline void kvm_flush_remote_tlbs_gfn(struct kvm *kvm, gfn_t gfn, int level)
+{
+	u64 pages = KVM_PAGES_PER_HPAGE(level);
+
+	kvm_flush_remote_tlbs_with_address(kvm, gfn, pages);
+}
+
 unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);

 extern int nx_huge_pages;
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 08b7932122ec..567691440ab0 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -673,8 +673,7 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm,
 	if (ret)
 		return ret;

-	kvm_flush_remote_tlbs_with_address(kvm, iter->gfn,
-					   KVM_PAGES_PER_HPAGE(iter->level));
+	kvm_flush_remote_tlbs_gfn(kvm, iter->gfn, iter->level);

 	/*
 	 * No other thread can overwrite the removed SPTE as they must either
@@ -1071,8 +1070,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
 		return RET_PF_RETRY;
 	else if (is_shadow_present_pte(iter->old_spte) &&
 		 !is_last_spte(iter->old_spte, iter->level))
-		kvm_flush_remote_tlbs_with_address(vcpu->kvm, iter->gfn,
-						   KVM_PAGES_PER_HPAGE(iter->level));
+		kvm_flush_remote_tlbs_gfn(vcpu->kvm, iter->gfn, iter->level);

 	/*
 	 * If the page fault was caused by a write but the page is write
--
2.31.1