From: Oliver Upton <oliver.upton@linux.dev>
To: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org
Cc: Oliver Upton <oliver.upton@linux.dev>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH] KVM: arm64: vgic: Don't hold config_lock while unregistering redistributors
Date: Mon, 19 Aug 2024 17:26:05 +0000 [thread overview]
Message-ID: <172408829924.848017.13221469817768550925.b4-ty@linux.dev> (raw)
In-Reply-To: <20240819125045.3474845-1-maz@kernel.org>
On Mon, 19 Aug 2024 13:50:45 +0100, Marc Zyngier wrote:
> We recently moved the teardown of the vgic part of a vcpu inside
> a critical section guarded by the config_lock. This teardown phase
> involves calling into kvm_io_bus_unregister_dev(), which takes the
> kvm->srcu lock.
>
> However, this violates the established order where kvm->srcu is
> taken on a memory fault (such as an MMIO access), possibly
> followed by taking the config_lock if the GIC emulation requires
> mutual exclusion from the other vcpus.
>
> [...]
Tested this w/ kvm-unit-tests, selftests, and a few VMs on a lockdep kernel.
Applied to kvmarm/fixes, thanks!
[1/1] KVM: arm64: vgic: Don't hold config_lock while unregistering redistributors
https://git.kernel.org/kvmarm/kvmarm/c/f616506754d3
--
Best,
Oliver
prev parent reply other threads:[~2024-08-19 17:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-19 12:50 [PATCH] KVM: arm64: vgic: Don't hold config_lock while unregistering redistributors Marc Zyngier
2024-08-19 15:20 ` Zenghui Yu
2024-08-19 17:26 ` Oliver Upton [this message]
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