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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marc Zyngier <maz@kernel.org>,
	Huacai Chen <chenhuacai@kernel.org>,
	Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
	Paul Mackerras <paulus@ozlabs.org>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
	kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
	linux-kernel@vger.kernel.org, Ben Gardon <bgardon@google.com>
Subject: Re: [PATCH 16/18] KVM: Don't take mmu_lock for range invalidation unless necessary
Date: Wed, 31 Mar 2021 20:52:12 +0000	[thread overview]
Message-ID: <YGTg/AWdieMM/mS7@google.com> (raw)
In-Reply-To: <6e7dc7d0-f5dc-85d9-1c50-d23b761b5ff3@redhat.com>

On Wed, Mar 31, 2021, Paolo Bonzini wrote:
> On 26/03/21 03:19, Sean Christopherson wrote:
> Also, related to the first part of the series, perhaps you could structure
> the series in a slightly different way:
> 
> 1) introduce the HVA walking API in common code, complete with on_lock and
> patch 15, so that you can use on_lock to increase mmu_notifier_seq
> 
> 2) then migrate all architectures including x86 to the new API
> 
> IOW, first half of patch 10 and all of patch 15; then the second half of
> patch 10; then patches 11-14.

100% agree with introducing on_lock separately from the conditional locking.

Not so sure about introducing conditional locking and then converting non-x86
archs.  I'd prefer to keep the conditional locking after arch conversion.
If something does go awry, it would be nice to be able to preciesly bisect to
the conditional locking.  Ditto if it needs to be reverted because it breaks an
arch.

  parent reply	other threads:[~2021-03-31 20:53 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26  2:19 [PATCH 00/18] KVM: Consolidate and optimize MMU notifiers Sean Christopherson
2021-03-26  2:19 ` [PATCH 01/18] KVM: x86/mmu: Coalesce TDP MMU TLB flushes when zapping collapsible SPTEs Sean Christopherson
2021-03-26  2:19 ` [PATCH 02/18] KVM: x86/mmu: Move flushing for "slot" handlers to caller for legacy MMU Sean Christopherson
2021-03-26  2:19 ` [PATCH 03/18] KVM: x86/mmu: Coalesce TLB flushes when zapping collapsible SPTEs Sean Christopherson
2021-03-26  2:19 ` [PATCH 04/18] KVM: x86/mmu: Coalesce TLB flushes across address spaces for gfn range zap Sean Christopherson
2021-03-26  2:19 ` [PATCH 05/18] KVM: x86/mmu: Pass address space ID to __kvm_tdp_mmu_zap_gfn_range() Sean Christopherson
2021-03-26  2:19 ` [PATCH 06/18] KVM: x86/mmu: Pass address space ID to TDP MMU root walkers Sean Christopherson
2021-03-26  2:19 ` [PATCH 07/18] KVM: x86/mmu: Use leaf-only loop for walking TDP SPTEs when changing SPTE Sean Christopherson
2021-03-26  2:19 ` [PATCH 08/18] KVM: Move prototypes for MMU notifier callbacks to generic code Sean Christopherson
2021-03-26  2:19 ` [PATCH 09/18] KVM: Move arm64's MMU notifier trace events " Sean Christopherson
2021-03-26  2:19 ` [PATCH 10/18] KVM: Move x86's MMU notifier memslot walkers " Sean Christopherson
2021-03-31  7:52   ` Paolo Bonzini
2021-03-31 16:20     ` Sean Christopherson
2021-03-31 16:36       ` Paolo Bonzini
2021-03-26  2:19 ` [PATCH 11/18] KVM: arm64: Convert to the gfn-based MMU notifier callbacks Sean Christopherson
2021-03-26  2:19 ` [PATCH 12/18] KVM: MIPS/MMU: " Sean Christopherson
2021-03-31  7:41   ` Paolo Bonzini
2021-03-26  2:19 ` [PATCH 13/18] KVM: PPC: " Sean Christopherson
2021-03-26  2:19 ` [PATCH 14/18] KVM: Kill off the old hva-based " Sean Christopherson
2021-03-26  2:19 ` [PATCH 15/18] KVM: Take mmu_lock when handling MMU notifier iff the hva hits a memslot Sean Christopherson
2021-03-26  2:19 ` [PATCH 16/18] KVM: Don't take mmu_lock for range invalidation unless necessary Sean Christopherson
2021-03-31  7:52   ` Paolo Bonzini
2021-03-31  8:35   ` Paolo Bonzini
2021-03-31 16:41     ` Sean Christopherson
2021-03-31 16:47       ` Paolo Bonzini
2021-03-31 19:47         ` Sean Christopherson
2021-03-31 20:42           ` Paolo Bonzini
2021-03-31 21:05             ` Sean Christopherson
2021-03-31 21:22               ` Sean Christopherson
2021-03-31 21:36                 ` Paolo Bonzini
2021-03-31 21:35               ` Paolo Bonzini
2021-03-31 21:47                 ` Sean Christopherson
2021-03-31 20:15     ` Sean Christopherson
2021-03-31 20:30       ` Paolo Bonzini
2021-03-31 20:52     ` Sean Christopherson [this message]
2021-03-31 21:00       ` Paolo Bonzini
2021-03-26  2:19 ` [PATCH 17/18] KVM: x86/mmu: Allow yielding during MMU notifier unmap/zap, if possible Sean Christopherson
2021-03-26  2:19 ` [PATCH 18/18] KVM: x86/mmu: Drop trace_kvm_age_page() tracepoint Sean Christopherson
2021-03-30 18:32 ` [PATCH 00/18] KVM: Consolidate and optimize MMU notifiers Ben Gardon
2021-03-30 19:48   ` Paolo Bonzini
2021-03-30 19:58   ` Sean Christopherson
2021-03-31  7:57 ` Paolo Bonzini
2021-03-31  9:34   ` Marc Zyngier
2021-03-31  9:41     ` Paolo Bonzini

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