From: Will Deacon <will@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
Marc Zyngier <maz@kernel.org>, Oliver Upton <oupton@kernel.org>,
Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Fuad Tabba <tabba@google.com>,
Vincent Donnefort <vdonnefort@google.com>,
Mostafa Saleh <smostafa@google.com>
Subject: Re: [PATCH 02/30] KVM: arm64: Remove redundant 'pgt' pointer checks from MMU notifiers
Date: Fri, 9 Jan 2026 14:31:51 +0000 [thread overview]
Message-ID: <aWERVxw-57pzi6ko@willie-the-truck> (raw)
In-Reply-To: <7g66xbfmfqf67qcowjuu725h3l33ecxhkffmlzxsjtbusk5eor@khlpkp7jdfzr>
On Tue, Jan 06, 2026 at 02:32:12PM +0000, Quentin Perret wrote:
> On Monday 05 Jan 2026 at 15:49:10 (+0000), Will Deacon wrote:
> > The MMU notifiers are registered by kvm_init_mmu_notifier() only after
> > kvm_arch_init_vm() has returned successfully. Since the latter function
> > initialises the 'kvm->arch.mmu.pgt' pointer (and allocates the VM handle
> > when pKVM is enabled), the initialisation checks in the MMU notifiers
> > are not required.
>
> It took me a while to remember, but I think these checks are needed for
> the free path rather than init. In particular, the doc for
> mmu_notifier_ops::release() (from which we free the pgt) says that it
> "can run concurrently with other mmu notifier" (see mmu_notifier.h), which
> is fun.
>
> Had you considered that path? If so, probably worth expanding in the
> commit description why this is safe?
Urgh....
Let me get back to you on that :)
Will
next prev parent reply other threads:[~2026-01-09 14:32 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 15:49 [PATCH 00/30] KVM: arm64: Add support for protected guest memory with pKVM Will Deacon
2026-01-05 15:49 ` [PATCH 01/30] KVM: arm64: Invert KVM_PGTABLE_WALK_HANDLE_FAULT to fix pKVM walkers Will Deacon
2026-01-06 14:33 ` Quentin Perret
2026-01-10 10:22 ` (subset) " Oliver Upton
2026-01-05 15:49 ` [PATCH 02/30] KVM: arm64: Remove redundant 'pgt' pointer checks from MMU notifiers Will Deacon
2026-01-06 14:32 ` Quentin Perret
2026-01-09 14:31 ` Will Deacon [this message]
2026-01-09 17:31 ` Will Deacon
2026-01-05 15:49 ` [PATCH 03/30] KVM: arm64: Rename __pkvm_pgtable_stage2_unmap() Will Deacon
2026-01-05 15:49 ` [PATCH 04/30] KVM: arm64: Don't advertise unsupported features for protected guests Will Deacon
2026-01-05 15:49 ` [PATCH 05/30] KVM: arm64: Expose self-hosted debug regs as RAZ/WI " Will Deacon
2026-01-05 15:49 ` [PATCH 06/30] KVM: arm64: Remove pointless is_protected_kvm_enabled() checks from hyp Will Deacon
2026-01-06 14:40 ` Quentin Perret
2026-01-09 14:23 ` Will Deacon
2026-01-05 15:49 ` [PATCH 07/30] KVM: arm64: Ignore MMU notifier callbacks for protected VMs Will Deacon
2026-01-05 15:49 ` [PATCH 08/30] KVM: arm64: Prevent unsupported memslot operations on " Will Deacon
2026-01-05 15:49 ` [PATCH 09/30] KVM: arm64: Split teardown hypercall into two phases Will Deacon
2026-01-05 15:49 ` [PATCH 10/30] KVM: arm64: Introduce __pkvm_host_donate_guest() Will Deacon
2026-01-06 14:48 ` Quentin Perret
2026-01-09 14:30 ` Will Deacon
2026-01-09 15:10 ` Quentin Perret
2026-01-05 15:49 ` [PATCH 11/30] KVM: arm64: Hook up donation hypercall to pkvm_pgtable_stage2_map() Will Deacon
2026-01-05 15:49 ` [PATCH 12/30] KVM: arm64: Handle aborts from protected VMs Will Deacon
2026-01-05 15:49 ` [PATCH 13/30] KVM: arm64: Introduce __pkvm_reclaim_dying_guest_page() Will Deacon
2026-01-06 16:26 ` Vincent Donnefort
2026-01-05 15:49 ` [PATCH 14/30] KVM: arm64: Hook up reclaim hypercall to pkvm_pgtable_stage2_destroy() Will Deacon
2026-01-06 14:59 ` Quentin Perret
2026-01-09 14:35 ` Will Deacon
2026-01-09 14:57 ` Quentin Perret
2026-01-05 15:49 ` [PATCH 15/30] KVM: arm64: Refactor enter_exception64() Will Deacon
2026-01-05 15:49 ` [PATCH 16/30] KVM: arm64: Inject SIGSEGV on illegal accesses Will Deacon
2026-01-05 15:49 ` [PATCH 17/30] KVM: arm64: Generalise kvm_pgtable_stage2_set_owner() Will Deacon
2026-01-06 15:20 ` Quentin Perret
2026-01-09 18:46 ` Will Deacon
2026-01-17 0:03 ` Will Deacon
2026-01-05 15:49 ` [PATCH 18/30] KVM: arm64: Introduce host_stage2_set_owner_metadata_locked() Will Deacon
2026-01-05 15:49 ` [PATCH 19/30] KVM: arm64: Annotate guest donations with handle and gfn in host stage-2 Will Deacon
2026-01-06 16:01 ` Fuad Tabba
2026-01-09 14:42 ` Will Deacon
2026-01-12 9:25 ` Fuad Tabba
2026-01-05 15:49 ` [PATCH 20/30] KVM: arm64: Introduce hypercall to force reclaim of a protected page Will Deacon
2026-01-06 15:44 ` Quentin Perret
2026-01-09 17:47 ` Will Deacon
2026-01-05 15:49 ` [PATCH 21/30] KVM: arm64: Reclaim faulting page from pKVM in spurious fault handler Will Deacon
2026-01-05 15:49 ` [PATCH 22/30] KVM: arm64: Return -EFAULT from VCPU_RUN on access to a poisoned pte Will Deacon
2026-01-06 15:54 ` Quentin Perret
2026-01-09 14:57 ` Will Deacon
2026-01-09 15:29 ` Quentin Perret
2026-01-09 17:35 ` Will Deacon
2026-01-05 15:49 ` [PATCH 23/30] KVM: arm64: Add hvc handler at EL2 for hypercalls from protected VMs Will Deacon
2026-01-06 15:52 ` Vincent Donnefort
2026-01-05 15:49 ` [PATCH 24/30] KVM: arm64: Implement the MEM_SHARE hypercall for " Will Deacon
2026-01-06 15:45 ` Vincent Donnefort
2026-01-09 15:01 ` Will Deacon
2026-01-05 15:49 ` [PATCH 25/30] KVM: arm64: Implement the MEM_UNSHARE " Will Deacon
2026-01-06 15:50 ` Vincent Donnefort
2026-01-05 15:49 ` [PATCH 26/30] KVM: arm64: Allow userspace to create protected VMs when pKVM is enabled Will Deacon
2026-01-05 15:49 ` [PATCH 27/30] KVM: arm64: Add some initial documentation for pKVM Will Deacon
2026-01-06 15:59 ` Vincent Donnefort
2026-01-09 15:04 ` Will Deacon
2026-01-05 15:49 ` [PATCH 28/30] KVM: arm64: Extend pKVM page ownership selftests to cover guest donation Will Deacon
2026-01-05 15:49 ` [PATCH 29/30] KVM: arm64: Register 'selftest_vm' in the VM table Will Deacon
2026-01-05 15:49 ` [PATCH 30/30] KVM: arm64: Extend pKVM page ownership selftests to cover forced reclaim Will Deacon
2026-03-13 15:31 ` [PATCH 00/30] KVM: arm64: Add support for protected guest memory with pKVM Mostafa Saleh
2026-04-20 8:02 ` Pavan Kondeti
2026-04-20 10:00 ` Will Deacon
2026-04-20 11:26 ` Pavan Kondeti
2026-04-21 4:15 ` Pavan Kondeti
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aWERVxw-57pzi6ko@willie-the-truck \
--to=will@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=joey.gouly@arm.com \
--cc=kvmarm@lists.linux.dev \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=maz@kernel.org \
--cc=oupton@kernel.org \
--cc=qperret@google.com \
--cc=smostafa@google.com \
--cc=suzuki.poulose@arm.com \
--cc=tabba@google.com \
--cc=vdonnefort@google.com \
--cc=yuzenghui@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox