From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Shuah Khan <shuah@kernel.org>, Oliver Upton <oupton@kernel.org>,
Fuad Tabba <fuad.tabba@linux.dev>,
Peter Maydell <peter.maydell@linaro.org>,
Leonardo Bras <leo.bras@arm.com>,
Wei-Lin Chang <weilin.chang@arm.com>,
Yao Yuan <yaoyuan@linux.alibaba.com>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
kvmarm@lists.linux.dev, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v20 03/14] KVM: arm64: Manage GCS access and registers for guests
Date: Wed, 9 Sep 2026 12:34:11 +0100 [thread overview]
Message-ID: <aqFEGDkyZbXp1B0V@gremlin> (raw)
In-Reply-To: <1effee02-41f0-4680-9a6f-9b9f12459ec1@sirena.org.uk>
On Mon, Sep 07, 2026 at 03:55:43PM +0100, Mark Brown wrote:
> On Mon, Sep 07, 2026 at 03:14:34PM +0100, Lorenzo Stoakes (ARM) wrote:
> > On Fri, Sep 04, 2026 at 10:07:49PM +0100, Mark Brown wrote:
> > > On Fri, Sep 04, 2026 at 09:54:51AM +0100, Lorenzo Stoakes (ARM) wrote:
>
> > > I think the best thing overall would be to leave the runtime paths as
> > > they are and refuse to run with an architecturally invalid setup, that
> > > would avoid bloating the fast path.
>
> > Ack, it'd be nice to not have to worry about that.
>
> > Presumably we definitely want an oops on a GCS violation in general?
>
> Yes, the guest is going to want GCS exceptions delivering if they've
> enabled them and something triggers them. It might also be relying on
> the GCS for stack traces even if nothing triggers any GCS related fault.
OK so the answer seems definitely to be disallowing the invalid config at
runtime then I think! :)
--
Cheers, Lorenzo
next prev parent reply other threads:[~2026-09-09 11:34 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-01 21:46 [PATCH v20 00/14] KVM: arm64: Provide guest support for GCS Mark Brown
2026-09-01 21:46 ` [PATCH v20 01/14] arm64/gcs: Ensure FGTs for EL1 GCS instructions are disabled Mark Brown
2026-09-03 16:10 ` Lorenzo Stoakes (ARM)
2026-09-01 21:47 ` [PATCH v20 02/14] KVM: arm64: Fix FGT mapping for HFGITR_EL2.nGCSEPP Mark Brown
2026-09-03 16:23 ` Lorenzo Stoakes (ARM)
2026-09-03 19:29 ` Mark Brown
2026-09-01 21:47 ` [PATCH v20 03/14] KVM: arm64: Manage GCS access and registers for guests Mark Brown
2026-09-01 22:00 ` sashiko-bot
2026-09-02 16:44 ` Leonardo Bras
2026-09-03 20:52 ` Mark Brown
2026-09-03 18:13 ` Lorenzo Stoakes (ARM)
2026-09-03 20:41 ` Mark Brown
2026-09-04 8:54 ` Lorenzo Stoakes (ARM)
2026-09-04 21:07 ` Mark Brown
2026-09-07 14:14 ` Lorenzo Stoakes (ARM)
2026-09-07 14:55 ` Mark Brown
2026-09-09 11:34 ` Lorenzo Stoakes (ARM) [this message]
2026-09-01 21:47 ` [PATCH v20 04/14] KVM: arm64: Ensure GCS memory effects are visible Mark Brown
2026-09-01 22:06 ` sashiko-bot
2026-09-02 16:30 ` Leonardo Bras
2026-09-04 12:16 ` Lorenzo Stoakes (ARM)
2026-09-01 21:47 ` [PATCH v20 05/14] KVM: arm64: Set PSTATE.EXLOCK when entering an exception Mark Brown
2026-09-01 22:06 ` sashiko-bot
2026-09-03 14:25 ` Leonardo Bras
2026-09-03 16:20 ` Mark Brown
2026-09-03 16:40 ` Leonardo Bras
2026-09-04 13:04 ` Lorenzo Stoakes (ARM)
2026-09-01 21:47 ` [PATCH v20 06/14] KVM: arm64: Validate GCS exception lock when emulating ERET Mark Brown
2026-09-03 15:37 ` Leonardo Bras
2026-09-03 19:22 ` Mark Brown
2026-09-04 13:16 ` Leonardo Bras
2026-09-04 21:56 ` Mark Brown
2026-09-07 10:55 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 07/14] KVM: arm64: Forward GCS exceptions to nested guests Mark Brown
2026-09-01 22:09 ` sashiko-bot
2026-09-09 13:00 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 08/14] KVM: arm64: Enforce EXLOCK for SPSR and ELR Mark Brown
2026-09-01 22:15 ` sashiko-bot
2026-09-01 22:48 ` Mark Brown
2026-09-09 14:35 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 09/14] KVM: arm64: Allow GCS to be enabled for guests Mark Brown
2026-09-09 16:34 ` Leonardo Bras
2026-09-09 16:45 ` Mark Brown
2026-09-01 21:47 ` [PATCH v20 10/14] KVM: selftests: arm64: Add GCS registers to get-reg-list Mark Brown
2026-09-01 22:05 ` sashiko-bot
2026-09-09 16:46 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 11/14] KVM: selftests: arm64: Add GCS to set_id_regs Mark Brown
2026-09-09 16:55 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 12/14] KVM: selftests: arm64: Only restore SPSR_EL1 and ELR_EL1 if they change Mark Brown
2026-09-09 17:03 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 13/14] tools: Synchronise the kernel esr.h Mark Brown
2026-09-01 22:08 ` sashiko-bot
2026-09-10 11:10 ` Leonardo Bras
2026-09-01 21:47 ` [PATCH v20 14/14] KVM: selftests: arm64: Add GCS EXLOCK exception emulation test Mark Brown
2026-09-01 22:16 ` sashiko-bot
2026-09-10 17:20 ` Leonardo Bras
2026-09-10 18:26 ` Mark Brown
2026-09-11 11:02 ` Leonardo Bras
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