linux-kernel - [PATCH 02/14] KVM: x86/mmu: Don't unnecessarily write-protect small pages in TDP MMU

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Message-Id: <20210213005015.1651772-3-seanjc@google.com>
Date:   Fri, 12 Feb 2021 16:50:03 -0800
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>,
        Makarand Sonare <makarandsonare@...gle.com>
Subject: [PATCH 02/14] KVM: x86/mmu: Don't unnecessarily write-protect small
 pages in TDP MMU

Respect start_level when write-protect pages in the TDP MMU for dirty
logging.  When the dirty bitmaps are initialized with all bits set, small
pages don't need to be write-protected as they've already been marked
dirty.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e507568cd55d..24325bdcd387 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5500,7 +5500,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
 	flush = slot_handle_level(kvm, memslot, slot_rmap_write_protect,
 				start_level, KVM_MAX_HUGEPAGE_LEVEL, false);
 	if (is_tdp_mmu_enabled(kvm))
-		flush |= kvm_tdp_mmu_wrprot_slot(kvm, memslot, PG_LEVEL_4K);
+		flush |= kvm_tdp_mmu_wrprot_slot(kvm, memslot, start_level);
 	write_unlock(&kvm->mmu_lock);
 
 	/*
-- 
2.30.0.478.g8a0d178c01-goog