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: Wed, 7 Dec 2022 19:33:18 +0000 [thread overview]
Message-ID: <Y5DqfrC4a6EpiCk7@sirena.org.uk> (raw)
In-Reply-To: <87y1rjrq7z.wl-maz@kernel.org>
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On Wed, Dec 07, 2022 at 07:03:28PM +0000, Marc Zyngier wrote:
> Mark Brown <broonie@kernel.org> wrote:
> > On Mon, Dec 05, 2022 at 06:06:24PM +0000, Marc Zyngier wrote:
> > > Mark Brown <broonie@kernel.org> wrote:
> > > > 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.
> I'm not hell bent on it, and if we can spot the issue early, that's
> fine by me. But let's then disable the feature if the implementation
> lacks some essential dependencies.
> A simple check on ID_AA64MMFR1_EL1.HCX when detecting FEAT_NMI should
> do the trick.
Hrm, we should really only check if EL2 is implemented since that is a
valid configuration in which HCX is moot, and there's a case for only
checking when we entered the kernel at EL2 since otherwise any traps to
EL2 are not really our problem and I can see why EL2 might not let EL1
know about the feature even if it really should.
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next prev parent reply other threads:[~2022-12-07 19:34 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
2022-12-07 19:03 ` Marc Zyngier
2022-12-07 19:33 ` Mark Brown [this message]
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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