linux-kernel - [PATCH V5 10/10] KVM/MMU: Flush tlb directly in the kvm_zap_gfn

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Message-Id: <20181108091447.8275-11-Tianyu.Lan@microsoft.com>
Date:   Thu,  8 Nov 2018 17:14:47 +0800
From:   ltykernel@...il.com
To:     unlisted-recipients:; (no To-header on input)
Cc:     Lan Tianyu <Tianyu.Lan@...rosoft.com>, pbonzini@...hat.com,
        rkrcmar@...hat.com, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, hpa@...or.com, x86@...nel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, michael.h.kelley@...rosoft.com,
        kys@...rosoft.com, vkuznets@...hat.com, linux@...linux.org.uk
Subject: [PATCH V5 10/10] KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()

From: Lan Tianyu <Tianyu.Lan@...rosoft.com>

Originally, flush tlb is done by slot_handle_level_range(). This patch
is to flush tlb directly in the kvm_zap_gfn_range() when range
flush is available.

Signed-off-by: Lan Tianyu <Tianyu.Lan@...rosoft.com>
---
Change since v4:
	Move operation of setting flush_tlb out of for loop.
---
 arch/x86/kvm/mmu.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 39e0e2572710..898560b0807c 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5633,8 +5633,13 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 {
 	struct kvm_memslots *slots;
 	struct kvm_memory_slot *memslot;
+	bool flush_tlb = true;
+	bool flush = false;
 	int i;
 
+	if (kvm_available_flush_tlb_with_range())
+		flush_tlb = false;
+
 	spin_lock(&kvm->mmu_lock);
 	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
 		slots = __kvm_memslots(kvm, i);
@@ -5646,12 +5651,17 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 			if (start >= end)
 				continue;
 
-			slot_handle_level_range(kvm, memslot, kvm_zap_rmapp,
-						PT_PAGE_TABLE_LEVEL, PT_MAX_HUGEPAGE_LEVEL,
-						start, end - 1, true);
+			flush |= slot_handle_level_range(kvm, memslot,
+					kvm_zap_rmapp, PT_PAGE_TABLE_LEVEL,
+					PT_MAX_HUGEPAGE_LEVEL, start,
+					end - 1, flush_tlb);
 		}
 	}
 
+	if (flush)
+		kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
+				gfn_end - gfn_start + 1);
+
 	spin_unlock(&kvm->mmu_lock);
 }
 
-- 
2.14.4