From: Catalin Marinas <catalin.marinas@arm.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, maz@kernel.org,
will@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, steven.price@arm.com,
aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com,
joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com,
linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com,
sdonthineni@nvidia.com, alpergun@google.com,
fj0570is@fujitsu.com, WeiLin.Chang@arm.com,
lpieralisi@kernel.org, enju.kohei@fujitsu.com
Subject: Re: [PATCH v18] arm64: mm: Handle Granule Protection Faults (GPFs)
Date: Thu, 17 Sep 2026 08:58:25 +0100 [thread overview]
Message-ID: <aqudod8kM5AjkCFY@arm.com> (raw)
In-Reply-To: <aqrGPK0lFBFXL2qY@arm.com>
On Wed, Sep 16, 2026 at 05:39:24PM +0100, Catalin Marinas wrote:
> However, can we end up delegating a non-guest_memfd memslot page as
> protected?
>
> I played a bit with codex and it reckons it's possible if a guest_memfd
> memslot is deleted after its IPA range has been initialised with
> RIPAS=RAM. Removing the memslot unmaps and undelegates any data pages
> but leaves the RMM state as RAM. The VMM can then install an ordinary
> memslot over the same GPA range.
After some more digging, I think RIPAS becomes DESTROYED after
undelegation but it doesn't change much. A subsequent guest access to
the private IPA still exits to the host which will attempt to delegate
it again even if it's no longer guest_memfd. RIPAS remains DESTROYED but
GPT is now REALM (and potentially a valid user mapping).
--
Catalin
next prev parent reply other threads:[~2026-09-17 7:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-13 7:04 [PATCH v18] arm64: mm: Handle Granule Protection Faults (GPFs) Suzuki K Poulose
2026-09-16 16:39 ` Catalin Marinas
2026-09-16 16:56 ` Catalin Marinas
2026-09-17 7:58 ` Catalin Marinas [this message]
2026-09-17 9:03 ` Suzuki K Poulose
2026-09-17 10:36 ` Catalin Marinas
2026-09-22 8:16 ` Suzuki K Poulose
2026-09-22 13:21 ` Suzuki K Poulose
2026-09-22 14:49 ` Catalin Marinas
2026-09-22 15:14 ` Suzuki K Poulose
2026-09-28 11:01 ` Suzuki K Poulose
2026-09-29 10:40 ` Catalin Marinas
2026-09-29 10:47 ` Suzuki K Poulose
2026-09-22 17:15 ` Will Deacon
2026-09-23 11:06 ` Catalin Marinas
2026-09-23 15:45 ` Will Deacon
2026-09-23 16:04 ` Suzuki K Poulose
2026-09-24 15:43 ` Catalin Marinas
2026-09-25 17:07 ` Catalin Marinas
2026-09-28 10:38 ` Suzuki K Poulose
2026-09-29 10:30 ` Catalin Marinas
2026-09-29 10:42 ` Suzuki K Poulose
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