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From: Marc Zyngier <maz@kernel.org>
To: Suraj Jitindar Singh <surajjs@amazon.com>
Cc: <stable@vger.kernel.org>, <james.morse@arm.com>,
	<alexandru.elisei@arm.com>, <suzuki.poulose@arm.com>,
	<oliver.upton@linux.dev>, <catalin.marinas@arm.com>,
	<linux-arm-kernel@lists.infradead.org>, <kvmarm@lists.linux.dev>,
	<kvmarm@lists.cs.columbia.edu>, <linux-kernel@vger.kernel.org>,
	<sjitindarsingh@gmail.com>, Will Deacon <will@kernel.org>,
	Quentin Perret <qperret@google.com>
Subject: Re: [PATCH stable 6.1.y 2/2] KVM: arm64: Prevent unconditional donation of unmapped regions from the host
Date: Thu, 21 Sep 2023 08:15:36 +0100	[thread overview]
Message-ID: <877cok3skn.wl-maz@kernel.org> (raw)
In-Reply-To: <20230920192729.694309-2-surajjs@amazon.com>

On Wed, 20 Sep 2023 20:27:29 +0100,
Suraj Jitindar Singh <surajjs@amazon.com> wrote:
> 
> From: Will Deacon <will@kernel.org>
> 
> commit 09cce60bddd6461a93a5bf434265a47827d1bc6f upstream.
> 
> Since host stage-2 mappings are created lazily, we cannot rely solely on
> the pte in order to recover the target physical address when checking a
> host-initiated memory transition as this permits donation of unmapped
> regions corresponding to MMIO or "no-map" memory.
> 
> Instead of inspecting the pte, move the addr_is_allowed_memory() check
> into the host callback function where it is passed the physical address
> directly from the walker.
> 
> Cc: Quentin Perret <qperret@google.com>
> Fixes: e82edcc75c4e ("KVM: arm64: Implement do_share() helper for sharing memory")
> Signed-off-by: Will Deacon <will@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/r/20230518095844.1178-1-will@kernel.org
> [ bp: s/ctx->addr/addr in __check_page_state_visitor due to missing commit
>       "KVM: arm64: Combine visitor arguments into a context structure"
>       in stable.
> ]

Same question.

> Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>

Again, I find this backport pretty pointless. What is the rationale
for it?

	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: Suraj Jitindar Singh <surajjs@amazon.com>
Cc: <stable@vger.kernel.org>, <james.morse@arm.com>,
	<alexandru.elisei@arm.com>, <suzuki.poulose@arm.com>,
	<oliver.upton@linux.dev>, <catalin.marinas@arm.com>,
	<linux-arm-kernel@lists.infradead.org>, <kvmarm@lists.linux.dev>,
	<kvmarm@lists.cs.columbia.edu>, <linux-kernel@vger.kernel.org>,
	<sjitindarsingh@gmail.com>, Will Deacon <will@kernel.org>,
	Quentin Perret <qperret@google.com>
Subject: Re: [PATCH stable 6.1.y 2/2] KVM: arm64: Prevent unconditional donation of unmapped regions from the host
Date: Thu, 21 Sep 2023 08:15:36 +0100	[thread overview]
Message-ID: <877cok3skn.wl-maz@kernel.org> (raw)
In-Reply-To: <20230920192729.694309-2-surajjs@amazon.com>

On Wed, 20 Sep 2023 20:27:29 +0100,
Suraj Jitindar Singh <surajjs@amazon.com> wrote:
> 
> From: Will Deacon <will@kernel.org>
> 
> commit 09cce60bddd6461a93a5bf434265a47827d1bc6f upstream.
> 
> Since host stage-2 mappings are created lazily, we cannot rely solely on
> the pte in order to recover the target physical address when checking a
> host-initiated memory transition as this permits donation of unmapped
> regions corresponding to MMIO or "no-map" memory.
> 
> Instead of inspecting the pte, move the addr_is_allowed_memory() check
> into the host callback function where it is passed the physical address
> directly from the walker.
> 
> Cc: Quentin Perret <qperret@google.com>
> Fixes: e82edcc75c4e ("KVM: arm64: Implement do_share() helper for sharing memory")
> Signed-off-by: Will Deacon <will@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/r/20230518095844.1178-1-will@kernel.org
> [ bp: s/ctx->addr/addr in __check_page_state_visitor due to missing commit
>       "KVM: arm64: Combine visitor arguments into a context structure"
>       in stable.
> ]

Same question.

> Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>

Again, I find this backport pretty pointless. What is the rationale
for it?

	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

  reply	other threads:[~2023-09-21  7:15 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-20 19:27 [PATCH stable 6.1.y 1/2] KVM: arm64: Prevent the donation of no-map pages Suraj Jitindar Singh
2023-09-20 19:27 ` Suraj Jitindar Singh
2023-09-20 19:27 ` [PATCH stable 6.1.y 2/2] KVM: arm64: Prevent unconditional donation of unmapped regions from the host Suraj Jitindar Singh
2023-09-20 19:27   ` Suraj Jitindar Singh
2023-09-21  7:15   ` Marc Zyngier [this message]
2023-09-21  7:15     ` Marc Zyngier
2023-09-21 22:25     ` Suraj Jitindar Singh
2023-09-21 22:25       ` Suraj Jitindar Singh
2023-09-21  7:13 ` [PATCH stable 6.1.y 1/2] KVM: arm64: Prevent the donation of no-map pages Marc Zyngier
2023-09-21  7:13   ` Marc Zyngier
2023-09-21 22:22   ` Jitindar Singh, Suraj
2023-09-21 22:22     ` Jitindar Singh, Suraj
2023-09-22  9:25     ` Greg KH
2023-09-22  9:25       ` Greg KH
2023-09-22 10:08     ` Marc Zyngier
2023-09-22 10:08       ` Marc Zyngier

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