From: David Matlack <dmatlack@google.com>
To: James Houghton <jthoughton@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Paolo Bonzini <pbonzini@redhat.com>, Yu Zhao <yuzhao@google.com>,
Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
Sean Christopherson <seanjc@google.com>,
Jonathan Corbet <corbet@lwn.net>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Shaoqin Huang <shahuang@redhat.com>,
Gavin Shan <gshan@redhat.com>,
Ricardo Koller <ricarkol@google.com>,
Raghavendra Rao Ananta <rananta@google.com>,
Ryan Roberts <ryan.roberts@arm.com>,
David Rientjes <rientjes@google.com>,
Axel Rasmussen <axelrasmussen@google.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
kvm@vger.kernel.org, linux-mm@kvack.org,
linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v3 5/7] KVM: x86: Participate in bitmap-based PTE aging
Date: Fri, 12 Apr 2024 13:44:41 -0700 [thread overview]
Message-ID: <ZhmdOb7lAd3DM5Tq@google.com> (raw)
In-Reply-To: <20240401232946.1837665-6-jthoughton@google.com>
On 2024-04-01 11:29 PM, James Houghton wrote:
> Only handle the TDP MMU case for now. In other cases, if a bitmap was
> not provided, fallback to the slowpath that takes mmu_lock, or, if a
> bitmap was provided, inform the caller that the bitmap is unreliable.
I think this patch will trigger a lockdep assert in
kvm_tdp_mmu_age_gfn_range
kvm_tdp_mmu_handle_gfn
for_each_tdp_mmu_root
__for_each_tdp_mmu_root
kvm_lockdep_assert_mmu_lock_held
... because it walks tdp_mmu_roots without holding mmu_lock.
Yu's patch[1] added a lockless walk to the TDP MMU. We'd need something
similar here and also update the comment above tdp_mmu_roots describing
how tdp_mmu_roots can be read locklessly.
[1] https://lore.kernel.org/kvmarm/ZItX64Bbx5vdjo9M@google.com/
next prev parent reply other threads:[~2024-04-12 20:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-01 23:29 [PATCH v3 0/7] mm/kvm: Improve parallelism for access bit harvesting James Houghton
2024-04-01 23:29 ` [PATCH v3 1/7] mm: Add a bitmap into mmu_notifier_{clear,test}_young James Houghton
2024-04-04 18:52 ` David Hildenbrand
2024-04-09 18:31 ` James Houghton
2024-04-09 19:35 ` David Hildenbrand
2024-04-11 0:35 ` James Houghton
2024-04-12 18:45 ` David Matlack
2024-04-19 20:34 ` James Houghton
2024-04-01 23:29 ` [PATCH v3 2/7] KVM: Move MMU notifier function declarations James Houghton
2024-04-01 23:29 ` [PATCH v3 3/7] KVM: Add basic bitmap support into kvm_mmu_notifier_test/clear_young James Houghton
2024-04-12 20:28 ` David Matlack
2024-04-19 20:41 ` James Houghton
2024-04-01 23:29 ` [PATCH v3 4/7] KVM: x86: Move tdp_mmu_enabled and shadow_accessed_mask James Houghton
2024-04-01 23:29 ` [PATCH v3 5/7] KVM: x86: Participate in bitmap-based PTE aging James Houghton
2024-04-11 17:08 ` David Matlack
2024-04-11 17:28 ` David Matlack
2024-04-11 18:00 ` David Matlack
2024-04-11 18:07 ` David Matlack
2024-04-19 20:47 ` James Houghton
2024-04-19 21:06 ` David Matlack
2024-04-19 21:48 ` James Houghton
2024-04-21 0:19 ` Yu Zhao
2024-04-12 20:44 ` David Matlack [this message]
2024-04-19 20:54 ` James Houghton
2024-04-01 23:29 ` [PATCH v3 6/7] KVM: arm64: " James Houghton
2024-04-02 4:06 ` Yu Zhao
2024-04-02 7:00 ` Oliver Upton
2024-04-02 7:33 ` Marc Zyngier
2024-04-01 23:29 ` [PATCH v3 7/7] mm: multi-gen LRU: use mmu_notifier_test_clear_young() James Houghton
2024-04-12 18:41 ` [PATCH v3 0/7] mm/kvm: Improve parallelism for access bit harvesting David Matlack
2024-04-19 20:57 ` James Houghton
2024-04-19 22:23 ` Oliver Upton
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