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From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Ben Gardon <bgardon@google.com>
Subject: [PATCH] KVM: MMU: protect TDP MMU pages only down to required level
Date: Fri,  2 Apr 2021 08:17:04 -0400	[thread overview]
Message-ID: <20210402121704.3424115-1-pbonzini@redhat.com> (raw)

When using manual protection of dirty pages, it is not necessary
to protect nested page tables down to the 4K level; instead KVM
can protect only hugepages in order to split them lazily, and
delay write protection at 4K-granularity until KVM_CLEAR_DIRTY_LOG.
This was overlooked in the TDP MMU, so do it there as well.

Fixes: a6a0b05da9f37 ("kvm: x86/mmu: Support dirty logging for the TDP MMU")
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.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 efb41f31e80a..0d92a269c5fa 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5538,7 +5538,7 @@ 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);
 
 	/*
-- 
2.26.2


             reply	other threads:[~2021-04-02 12:17 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-02 12:17 Paolo Bonzini [this message]
2021-04-06  6:26 ` Keqian Zhu
2021-04-06 23:38   ` Sean Christopherson
2021-04-07  1:31     ` Keqian Zhu

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