From: Sean Christopherson <seanjc@google.com>
To: Ben Gardon <bgardon@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.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,
Hou Wenlong <houwenlong93@linux.alibaba.com>
Subject: Re: [PATCH 09/28] KVM: x86/mmu: Require mmu_lock be held for write in unyielding root iter
Date: Mon, 22 Nov 2021 20:19:52 +0000 [thread overview]
Message-ID: <YZv7aIL8+7ESCfFc@google.com> (raw)
In-Reply-To: <CANgfPd9=ce+JT3xEJy=p5MEfvkMGovEaBEu8KmxiZAJ1AA958g@mail.gmail.com>
On Mon, Nov 22, 2021, Ben Gardon wrote:
> > + * Holding mmu_lock for write obviates the need for RCU protection as the list
> > + * is guaranteed to be stable.
> > + */
> > +#define for_each_tdp_mmu_root(_kvm, _root, _as_id) \
> > + list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link) \
> > if (kvm_mmu_page_as_id(_root) != _as_id) { \
> > + lockdep_assert_held_write(&(_kvm)->mmu_lock); \
>
> Did you mean for this lockdep to only be hit in this uncommon
> non-matching ASID case?
Yes and no. Yes, I intended what I wrote. No, this isn't intended to be limited
to a memslot address space mismatch, but at the time I wrote this I was apparently
lazy or inept :-)
In hindsight, this would be better:
/* blah blah blah */
static inline struct list_head *kvm_get_tdp_mmu_roots_exclusive(struct kvm *kvm)
{
lockdep_assert_held_write(&kvm->mmu_lock);
return &kvm->arch.tdp_mmu_roots;
}
#define for_each_tdp_mmu_root(_kvm, _root, _as_id) \
list_for_each_entry(_root, kvm_get_tdp_mmu_roots_exclusive(kvm), link) \
if (kvm_mmu_page_as_id(_root) != _as_id) { \
} else
next prev parent reply other threads:[~2021-11-22 20:19 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-20 4:50 [PATCH 00/28] KVM: x86/mmu: Overhaul TDP MMU zapping and flushing Sean Christopherson
2021-11-20 4:50 ` [PATCH 01/28] KVM: x86/mmu: Use yield-safe TDP MMU root iter in MMU notifier unmapping Sean Christopherson
2021-11-22 19:48 ` Ben Gardon
2021-11-30 8:03 ` Paolo Bonzini
2021-11-20 4:50 ` [PATCH 02/28] KVM: x86/mmu: Skip tlb flush if it has been done in zap_gfn_range() Sean Christopherson
2021-11-20 4:50 ` [PATCH 03/28] KVM: x86/mmu: Remove spurious TLB flushes in TDP MMU zap collapsible path Sean Christopherson
2021-11-20 4:50 ` [PATCH 04/28] KVM: x86/mmu: Retry page fault if root is invalidated by memslot update Sean Christopherson
2021-11-22 19:54 ` Ben Gardon
2021-12-01 20:49 ` Paolo Bonzini
2021-12-08 19:17 ` Sean Christopherson
2021-11-20 4:50 ` [PATCH 05/28] KVM: x86/mmu: Check for present SPTE when clearing dirty bit in TDP MMU Sean Christopherson
2021-11-22 19:57 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 06/28] KVM: x86/mmu: Formalize TDP MMU's (unintended?) deferred TLB flush logic Sean Christopherson
2021-11-20 4:50 ` [PATCH 07/28] KVM: x86/mmu: Document that zapping invalidated roots doesn't need to flush Sean Christopherson
2021-11-20 4:50 ` [PATCH 08/28] KVM: x86/mmu: Drop unused @kvm param from kvm_tdp_mmu_get_root() Sean Christopherson
2021-11-22 20:02 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 09/28] KVM: x86/mmu: Require mmu_lock be held for write in unyielding root iter Sean Christopherson
2021-11-22 20:10 ` Ben Gardon
2021-11-22 20:19 ` Sean Christopherson [this message]
2021-11-20 4:50 ` [PATCH 10/28] KVM: x86/mmu: Allow yielding when zapping GFNs for defunct TDP MMU root Sean Christopherson
2021-11-22 21:30 ` Ben Gardon
2021-11-22 22:40 ` Sean Christopherson
2021-11-22 23:03 ` Ben Gardon
2021-12-14 23:45 ` Sean Christopherson
2021-12-14 23:52 ` Sean Christopherson
2021-11-20 4:50 ` [PATCH 11/28] KVM: x86/mmu: Check for !leaf=>leaf, not PFN change, in TDP MMU SP removal Sean Christopherson
2021-11-20 4:50 ` [PATCH 12/28] KVM: x86/mmu: Batch TLB flushes from TDP MMU for MMU notifier change_spte Sean Christopherson
2021-11-22 21:45 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 13/28] KVM: x86/mmu: Drop RCU after processing each root in MMU notifier hooks Sean Christopherson
2021-11-22 21:47 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 14/28] KVM: x86/mmu: Add helpers to read/write TDP MMU SPTEs and document RCU Sean Christopherson
2021-11-22 21:55 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 15/28] KVM: x86/mmu: Take TDP MMU roots off list when invalidating all roots Sean Christopherson
2021-11-22 22:20 ` Ben Gardon
2021-11-22 23:08 ` Sean Christopherson
2021-11-23 0:03 ` Ben Gardon
2021-12-14 23:34 ` Sean Christopherson
2021-11-20 4:50 ` [PATCH 16/28] KVM: x86/mmu: WARN if old _or_ new SPTE is REMOVED in non-atomic path Sean Christopherson
2021-11-22 21:57 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 17/28] KVM: x86/mmu: Terminate yield-friendly walk if invalid root observed Sean Christopherson
2021-11-22 22:25 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 18/28] KVM: x86/mmu: Refactor low-level TDP MMU set SPTE helper to take raw vals Sean Christopherson
2021-11-22 22:29 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 19/28] KVM: x86/mmu: Zap only the target TDP MMU shadow page in NX recovery Sean Christopherson
2021-11-22 22:43 ` Ben Gardon
2021-11-23 1:16 ` Sean Christopherson
2021-11-23 19:35 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 20/28] KVM: x86/mmu: Use common TDP MMU zap helper for MMU notifier unmap hook Sean Christopherson
2021-11-22 22:49 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 21/28] KVM: x86/mmu: Add TDP MMU helper to zap a root Sean Christopherson
2021-11-22 22:54 ` Ben Gardon
2021-11-22 23:15 ` Sean Christopherson
2021-11-22 23:38 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 22/28] KVM: x86/mmu: Skip remote TLB flush when zapping all of TDP MMU Sean Christopherson
2021-11-22 23:00 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 23/28] KVM: x86/mmu: Use "zap root" path for "slow" zap of all TDP MMU SPTEs Sean Christopherson
2021-11-20 4:50 ` [PATCH 24/28] KVM: x86/mmu: Add dedicated helper to zap TDP MMU root shadow page Sean Christopherson
2021-11-23 1:04 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 25/28] KVM: x86/mmu: Require mmu_lock be held for write to zap TDP MMU range Sean Christopherson
2021-11-23 19:58 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 26/28] KVM: x86/mmu: Zap only TDP MMU leafs in kvm_zap_gfn_range() Sean Christopherson
2021-11-23 19:58 ` Ben Gardon
2021-11-20 4:50 ` [PATCH 27/28] KVM: x86/mmu: Do remote TLB flush before dropping RCU in TDP MMU resched Sean Christopherson
2021-11-23 19:58 ` Ben Gardon
2021-11-24 18:42 ` Sean Christopherson
2021-11-30 11:29 ` Paolo Bonzini
2021-11-30 15:45 ` Sean Christopherson
2021-11-30 16:16 ` Paolo Bonzini
2021-11-20 4:50 ` [PATCH 28/28] KVM: x86/mmu: Defer TLB flush to caller when freeing TDP MMU shadow pages Sean Christopherson
2021-11-23 20:12 ` Ben Gardon
2021-12-01 17:53 ` [PATCH 00/28] KVM: x86/mmu: Overhaul TDP MMU zapping and flushing David Matlack
2021-12-02 2:03 ` Sean Christopherson
2021-12-03 0:16 ` David Matlack
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