From: Mark Brown <broonie@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Lorenzo Pieralisi <lpieralisi@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Sami Mujawar <Sami.Mujawar@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev
Subject: Re: [PATCH v2 09/14] KVM: arm64: Hide FEAT_NMI from guests
Date: Mon, 5 Dec 2022 19:03:50 +0000 [thread overview]
Message-ID: <Y45Aluq2zJoQ828W@sirena.org.uk> (raw)
In-Reply-To: <86pmcxlo7z.wl-maz@kernel.org>
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On Mon, Dec 05, 2022 at 06:06:24PM +0000, Marc Zyngier wrote:
> Mark Brown <broonie@kernel.org> wrote:
> > FEAT_NMI is not yet useful to guests pending implementation of vGIC
> > support. Mask out the feature from the ID register and prevent guests
> > creating state in ALLINT.ALLINT by activating the trap on write provided
> > in HCRX_EL2.TALLINT when they are running. There is no trap available
> > for reads from ALLINT.
> > We do not need to check for FEAT_HCRX since it is mandatory since v8.7
> > and FEAT_NMI is a v8.8 feature.
> And yet you check for it in hyp-stub.S after having checked for
> FEAT_NMI. What gives?
Being aware that you have a strong preference for not having safety
checks for mandatory features I didn't add any here but noted it so
people could see why they were omitted. The checks in hyp-stub.S were
probably written before I'd checked the dependency situation out.
I can remove those checks if preferred but TBH given that the failure
mode in hyp-stub.S is typically going to be to die with no output if
something goes wrong it does feel like it's worth the extra couple of
instructions to double check things just in case, especially with the
virtual platforms being so easy to misconfigure.
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next prev parent reply other threads:[~2022-12-05 19:05 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-12 15:16 [PATCH v2 00/14] arm64/nmi: Support for FEAT_NMI Mark Brown
2022-11-12 15:16 ` [PATCH v2 01/14] arm64/booting: Document boot requirements " Mark Brown
2022-11-12 15:16 ` [PATCH v2 02/14] arm64/sysreg: Add definition for ICC_NMIAR1_EL1 Mark Brown
2022-11-12 15:16 ` [PATCH v2 03/14] arm64/sysreg: Add definition of ISR_EL1 Mark Brown
2022-12-05 16:45 ` Marc Zyngier
2022-11-12 15:16 ` [PATCH v2 04/14] arm64/sysreg: Add definitions for immediate versions of MSR ALLINT Mark Brown
2022-12-05 16:38 ` Marc Zyngier
2022-12-05 17:11 ` Mark Brown
2022-12-07 19:18 ` Marc Zyngier
2022-12-07 19:42 ` Mark Brown
2022-11-12 15:16 ` [PATCH v2 05/14] arm64/asm: Introduce assembly macros for managing ALLINT Mark Brown
2022-12-05 17:29 ` Marc Zyngier
2022-12-05 18:24 ` Mark Brown
2022-12-07 19:14 ` Marc Zyngier
2022-11-12 15:17 ` [PATCH v2 06/14] arm64/hyp-stub: Enable access to ALLINT Mark Brown
2022-12-05 17:50 ` Marc Zyngier
2022-11-12 15:17 ` [PATCH v2 07/14] arm64/idreg: Add an override for FEAT_NMI Mark Brown
2022-11-12 15:17 ` [PATCH v2 08/14] arm64/cpufeature: Detect PE support " Mark Brown
2022-12-05 18:03 ` Marc Zyngier
2022-12-05 19:32 ` Mark Brown
2022-12-07 19:06 ` Marc Zyngier
2022-11-12 15:17 ` [PATCH v2 09/14] KVM: arm64: Hide FEAT_NMI from guests Mark Brown
2022-12-05 18:06 ` Marc Zyngier
2022-12-05 19:03 ` Mark Brown [this message]
2022-12-07 19:03 ` Marc Zyngier
2022-12-07 19:33 ` Mark Brown
2022-11-12 15:17 ` [PATCH v2 10/14] arm64/nmi: Manage masking for superpriority interrupts along with DAIF Mark Brown
2022-12-05 18:47 ` Marc Zyngier
2022-12-05 20:52 ` Mark Brown
2022-12-08 17:19 ` Lorenzo Pieralisi
2022-12-12 14:03 ` Mark Brown
2022-12-13 8:37 ` Lorenzo Pieralisi
2022-12-13 13:15 ` Mark Brown
2022-12-15 13:32 ` Marc Zyngier
2022-12-12 14:40 ` Mark Rutland
2022-12-15 13:21 ` Mark Brown
2022-11-12 15:17 ` [PATCH v2 11/14] arm64/irq: Document handling of FEAT_NMI in irqflags.h Mark Brown
2022-11-12 15:17 ` [PATCH v2 12/14] arm64/nmi: Add handling of superpriority interrupts as NMIs Mark Brown
2022-12-07 11:03 ` Marc Zyngier
2022-12-07 13:24 ` Mark Brown
2022-12-07 18:57 ` Marc Zyngier
2022-12-07 19:15 ` Mark Brown
2022-11-12 15:17 ` [PATCH v2 13/14] arm64/nmi: Add Kconfig for NMI Mark Brown
2022-11-12 15:17 ` [PATCH v2 14/14] irqchip/gic-v3: Implement FEAT_GICv3_NMI support Mark Brown
2022-12-07 15:20 ` Marc Zyngier
2022-12-02 18:42 ` [PATCH v2 00/14] arm64/nmi: Support for FEAT_NMI Marc Zyngier
2022-12-03 8:25 ` Lorenzo Pieralisi
2022-12-03 9:45 ` Marc Zyngier
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