From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
James Harvey <jamespharvey20@gmail.com>,
Alex Willamson <alex.williamson@redhat.com>
Subject: [PATCH 11/11] KVM: x86/mmu: Skip invalid pages during zapping iff root_count is zero
Date: Thu, 12 Sep 2019 19:46:12 -0700 [thread overview]
Message-ID: <20190913024612.28392-12-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190913024612.28392-1-sean.j.christopherson@intel.com>
Do not skip invalid shadow pages when zapping obsolete pages if the
pages' root_count has reached zero, in which case the page can be
immediately zapped and freed.
Update the comment accordingly.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a7b14750cde9..5e41b1f77a6d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5692,11 +5692,12 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm)
break;
/*
- * Since we are reversely walking the list and the invalid
- * list will be moved to the head, skip the invalid page
- * can help us to avoid the infinity list walking.
+ * Skip invalid pages with a non-zero root count, zapping pages
+ * with a non-zero root count will never succeed, i.e. the page
+ * will get thrown back on active_mmu_pages and we'll get stuck
+ * in an infinite loop.
*/
- if (sp->role.invalid)
+ if (sp->role.invalid && sp->root_count)
continue;
/*
--
2.22.0
next prev parent reply other threads:[~2019-09-13 2:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 2:46 [PATCH 00/11] KVM: x86/mmu: Restore fast invalidate/zap flow Sean Christopherson
2019-09-13 2:46 ` [PATCH 01/11] KVM: x86/mmu: Reintroduce fast invalidate/zap for flushing memslot Sean Christopherson
2019-09-13 2:46 ` [PATCH 02/11] KVM: x86/mmu: Treat invalid shadow pages as obsolete Sean Christopherson
2019-09-13 2:46 ` [PATCH 03/11] KVM: x86/mmu: Use fast invalidate mechanism to zap MMIO sptes Sean Christopherson
2019-09-13 2:46 ` [PATCH 04/11] KVM: x86/mmu: Revert "Revert "KVM: MMU: show mmu_valid_gen in shadow page related tracepoints"" Sean Christopherson
2019-09-13 2:46 ` [PATCH 05/11] KVM: x86/mmu: Revert "Revert "KVM: MMU: add tracepoint for kvm_mmu_invalidate_all_pages"" Sean Christopherson
2019-09-13 2:46 ` [PATCH 06/11] KVM: x86/mmu: Revert "Revert "KVM: MMU: zap pages in batch"" Sean Christopherson
2019-09-13 2:46 ` [PATCH 07/11] KVM: x86/mmu: Revert "Revert "KVM: MMU: collapse TLB flushes when zap all pages"" Sean Christopherson
2019-09-13 2:46 ` [PATCH 08/11] KVM: x86/mmu: Revert "Revert "KVM: MMU: reclaim the zapped-obsolete page first"" Sean Christopherson
2019-09-13 2:46 ` [PATCH 09/11] KVM: x86/mmu: Revert "KVM: x86/mmu: Remove is_obsolete() call" Sean Christopherson
2019-09-13 2:46 ` [PATCH 10/11] KVM: x86/mmu: Explicitly track only a single invalid mmu generation Sean Christopherson
2019-09-13 2:46 ` Sean Christopherson [this message]
2019-09-13 22:11 ` [PATCH 00/11] KVM: x86/mmu: Restore fast invalidate/zap flow Paolo Bonzini
2019-09-16 17:07 ` Alex Williamson
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