From: Oliver Upton <oliver.upton@linux.dev>
To: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>,
Colton Lewis <coltonlewis@google.com>,
kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev
Subject: Re: [PATCH 3/3] KVM: arm64: Skip break phase when we have FEAT_BBM level 2
Date: Fri, 9 Jun 2023 14:59:50 +0000 [thread overview]
Message-ID: <ZIM+ZgFji/H3Y/9U@linux.dev> (raw)
In-Reply-To: <20230608172112.GA1606@willie-the-truck>
Hey Will,
On Thu, Jun 08, 2023 at 06:21:13PM +0100, Will Deacon wrote:
> > IIRC, Colton was testing largely with permission relaxation, and had
> > forward progress issues b.c. the stale TLB entry was never invalidated
> > in response to a permission fault.
>
> Would the series at:
>
> https://lore.kernel.org/r/5d8e1f752051173d2d1b5c3e14b54eb3506ed3ef.1684892404.git-series.apopple@nvidia.com
>
> help with that?
Heh, that's a rather interesting patch :)
I don't think it is directly related to the problem Colton encounters,
though the symptoms are similar. This crops up when KVM uses a stricter
permission set than the primary MMU, like lazy X for deferred I$
maintenance and write-protection for dirty logging. KVM policy led to
the stale TLB entry, so KVM is the one that needs to initiate the
invalidation.
--
Thanks,
Oliver
prev parent reply other threads:[~2023-06-09 15:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 17:01 [PATCH 0/3] Relax break-before-make use with FEAT_BBM Colton Lewis
2023-06-02 17:01 ` [PATCH 1/3] arm64: Add a capability for FEAT_BBM level 2 Colton Lewis
2023-06-05 15:07 ` Robin Murphy
2023-06-02 17:01 ` [PATCH 2/3] KVM: arm64: Clear possible conflict aborts Colton Lewis
2023-06-09 15:44 ` Oliver Upton
2023-06-02 17:01 ` [PATCH 3/3] KVM: arm64: Skip break phase when we have FEAT_BBM level 2 Colton Lewis
2023-06-04 8:23 ` Marc Zyngier
2023-06-05 21:36 ` Oliver Upton
2023-06-08 17:21 ` Will Deacon
2023-06-09 14:59 ` Oliver Upton [this message]
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