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From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Lai Jiangshan <laijs@linux.alibaba.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Avi Kivity <avi@redhat.com>,
	kvm@vger.kernel.org
Subject: [PATCH 1/7] KVM: X86: Fix missed remote tlb flush in rmap_write_protect()
Date: Tue, 24 Aug 2021 15:55:17 +0800	[thread overview]
Message-ID: <20210824075524.3354-2-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20210824075524.3354-1-jiangshanlai@gmail.com>

From: Lai Jiangshan <laijs@linux.alibaba.com>

When kvm->tlbs_dirty > 0, some rmaps might have been deleted
without flushing tlb remotely after kvm_sync_page().  If @gfn
was writable before and it's rmaps was deleted in kvm_sync_page(),
we need to flush tlb too even if __rmap_write_protect() doesn't
request it.

Fixes: 4731d4c7a077 ("KVM: MMU: out of sync shadow core")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
 arch/x86/kvm/mmu/mmu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4853c033e6ce..313918df1a10 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1420,6 +1420,14 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
 			rmap_head = gfn_to_rmap(gfn, i, slot);
 			write_protected |= __rmap_write_protect(kvm, rmap_head, true);
 		}
+		/*
+		 * When kvm->tlbs_dirty > 0, some rmaps might have been deleted
+		 * without flushing tlb remotely after kvm_sync_page().  If @gfn
+		 * was writable before and it's rmaps was deleted in kvm_sync_page(),
+		 * we need to flush tlb too.
+		 */
+		if (min_level == PG_LEVEL_4K && kvm->tlbs_dirty)
+			write_protected = true;
 	}
 
 	if (is_tdp_mmu_enabled(kvm))
@@ -5733,6 +5741,14 @@ 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);
+		/*
+		 * When kvm->tlbs_dirty > 0, some rmaps might have been deleted
+		 * without flushing tlb remotely after kvm_sync_page().  If @gfn
+		 * was writable before and it's rmaps was deleted in kvm_sync_page(),
+		 * we need to flush tlb too.
+		 */
+		if (start_level == PG_LEVEL_4K && kvm->tlbs_dirty)
+			flush = true;
 		write_unlock(&kvm->mmu_lock);
 	}
 
-- 
2.19.1.6.gb485710b


  reply	other threads:[~2021-08-24 17:59 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24  7:55 [PATCH 0/7] KVM: X86: MMU: misc fixes and cleanups Lai Jiangshan
2021-08-24  7:55 ` Lai Jiangshan [this message]
2021-09-02 21:38   ` [PATCH 1/7] KVM: X86: Fix missed remote tlb flush in rmap_write_protect() Sean Christopherson
2021-09-13  9:57   ` Maxim Levitsky
2021-08-24  7:55 ` [PATCH 2/7] KVM: X86: Synchronize the shadow pagetable before link it Lai Jiangshan
2021-09-02 23:40   ` Sean Christopherson
2021-09-02 23:54     ` Sean Christopherson
2021-09-03  0:44       ` Lai Jiangshan
2021-09-03 16:06         ` Sean Christopherson
2021-09-03 16:25           ` Lai Jiangshan
2021-09-03 16:40             ` Sean Christopherson
2021-09-03 17:00               ` Lai Jiangshan
2021-09-03 16:33           ` Lai Jiangshan
2021-09-03  0:51     ` Lai Jiangshan
2021-09-13 11:30     ` Maxim Levitsky
2021-09-13 20:49       ` Sean Christopherson
2021-09-13 22:31         ` Maxim Levitsky
2021-08-24  7:55 ` [PATCH 3/7] KVM: X86: Zap the invalid list after remote tlb flushing Lai Jiangshan
2021-09-02 21:54   ` Sean Christopherson
2021-08-24  7:55 ` [PATCH 4/7] KVM: X86: Remove FNAME(update_pte) Lai Jiangshan
2021-09-13  9:49   ` Maxim Levitsky
2021-08-24  7:55 ` [PATCH 5/7] KVM: X86: Don't unsync pagetables when speculative Lai Jiangshan
2021-09-13 11:02   ` Maxim Levitsky
2021-09-18  3:06     ` Lai Jiangshan
2021-08-24  7:55 ` [PATCH 6/7] KVM: X86: Don't check unsync if the original spte is writible Lai Jiangshan
2021-08-24  7:55 ` [PATCH 7/7] KVM: X86: Also prefetch the last range in __direct_pte_prefetch() Lai Jiangshan
2021-08-25 15:18   ` Sean Christopherson
2021-08-25 22:58     ` Lai Jiangshan
2021-08-31 18:02 ` [PATCH 0/7] KVM: X86: MMU: misc fixes and cleanups Lai Jiangshan
2021-08-31 21:57   ` Sean Christopherson

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