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From: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Gavin Shan <gshan@redhat.com>
Subject: Re: [PATCH 0/2] KVM: arm64: Address soft lockups due to I-cache CMOs
Date: Thu, 21 Sep 2023 08:39:45 +0100	[thread overview]
Message-ID: <875y443rge.wl-maz@kernel.org> (raw)
In-Reply-To: <20230920080133.944717-1-oliver.upton@linux.dev>

On Wed, 20 Sep 2023 09:01:31 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> Small series to address the soft lockups that Gavin hits when running
> KVM guests w/ hugepages on an Ampere Altra Max machine. While I
> absolutely loathe "fixing" the issue of slow I-cache CMOs in this way,
> I can't really think of an alternative.

I don't think there is any, unfortunately. I don't think this change
is inherently bad (we should have added something like this a long
while ago), but it scares me that these systems can apparently be
DoS'd from userspace or a guest...

Anyway:

Reviewed-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Gavin Shan <gshan@redhat.com>
Subject: Re: [PATCH 0/2] KVM: arm64: Address soft lockups due to I-cache CMOs
Date: Thu, 21 Sep 2023 08:39:45 +0100	[thread overview]
Message-ID: <875y443rge.wl-maz@kernel.org> (raw)
In-Reply-To: <20230920080133.944717-1-oliver.upton@linux.dev>

On Wed, 20 Sep 2023 09:01:31 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> Small series to address the soft lockups that Gavin hits when running
> KVM guests w/ hugepages on an Ampere Altra Max machine. While I
> absolutely loathe "fixing" the issue of slow I-cache CMOs in this way,
> I can't really think of an alternative.

I don't think there is any, unfortunately. I don't think this change
is inherently bad (we should have added something like this a long
while ago), but it scares me that these systems can apparently be
DoS'd from userspace or a guest...

Anyway:

Reviewed-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2023-09-21  7:39 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-20  8:01 [PATCH 0/2] KVM: arm64: Address soft lockups due to I-cache CMOs Oliver Upton
2023-09-20  8:01 ` Oliver Upton
2023-09-20  8:01 ` [PATCH 1/2] arm64: tlbflush: Rename MAX_TLBI_OPS Oliver Upton
2023-09-20  8:01   ` Oliver Upton
2023-09-21  3:27   ` Gavin Shan
2023-09-21  3:27     ` Gavin Shan
2023-09-22 10:25   ` Will Deacon
2023-09-22 10:25     ` Will Deacon
2023-09-20  8:01 ` [PATCH 2/2] KVM: arm64: Avoid soft lockups due to I-cache maintenance Oliver Upton
2023-09-20  8:01   ` Oliver Upton
2023-09-21  3:28   ` Gavin Shan
2023-09-21  3:28     ` Gavin Shan
2023-09-21  7:39 ` Marc Zyngier [this message]
2023-09-21  7:39   ` [PATCH 0/2] KVM: arm64: Address soft lockups due to I-cache CMOs Marc Zyngier
2023-09-22 17:56 ` Oliver Upton
2023-09-22 17:56   ` Oliver Upton

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