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From: Marc Zyngier <maz@kernel.org>
To: Mark Brown <broonie@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 06/14] arm64/hyp-stub: Enable access to ALLINT
Date: Mon, 05 Dec 2022 17:50:35 +0000	[thread overview]
Message-ID: <86sfhtloyc.wl-maz@kernel.org> (raw)
In-Reply-To: <20221112151708.175147-7-broonie@kernel.org>

On Sat, 12 Nov 2022 15:17:00 +0000,
Mark Brown <broonie@kernel.org> wrote:
> 
> In order to use NMIs we need to ensure that traps are disabled for it so
> update HCRX_EL2 to ensure that TALLINT is not set when we detect support
> for NMIs.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  arch/arm64/kernel/hyp-stub.S | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> index 2ee18c860f2a..4e0b06467973 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -151,6 +151,18 @@ SYM_CODE_START_LOCAL(__finalise_el2)
>  
>  .Lskip_sme:
>  
> +	// NMIs
> +	__check_override id_aa64pfr1 ID_AA64PFR1_EL1_NMI_SHIFT 4 .Linit_nmi .Lskip_nmi

Err.., What makes sure that x1 contains id_aa64pfr1_el1, as per the
big fat warning at the beginning of the file?? If you have SME, x1
will contain some other junk... Really, this must be written as:

	check_override id_aa64pfr1 ID_AA64PFR1_EL1_NMI_SHIFT .Linit_nmi .Lskip_nmi

> +.Linit_nmi:
> +	mrs	x1, id_aa64mmfr1_el1		// HCRX_EL2 present?
> +	ubfx	x1, x1, #ID_AA64MMFR1_EL1_HCX_SHIFT, #4
> +	cbz	x1, .Lskip_nmi
> +
> +	mrs_s	x1, SYS_HCRX_EL2
> +	and	x1, x1, #~HCRX_EL2_TALLINT_MASK	// Don't trap ALLINT

A nicer way of writing this is:

	bic	x1, x1, #HCRX_EL2_TALLINT_MASK

	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: Mark Brown <broonie@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 06/14] arm64/hyp-stub: Enable access to ALLINT
Date: Mon, 05 Dec 2022 17:50:35 +0000	[thread overview]
Message-ID: <86sfhtloyc.wl-maz@kernel.org> (raw)
In-Reply-To: <20221112151708.175147-7-broonie@kernel.org>

On Sat, 12 Nov 2022 15:17:00 +0000,
Mark Brown <broonie@kernel.org> wrote:
> 
> In order to use NMIs we need to ensure that traps are disabled for it so
> update HCRX_EL2 to ensure that TALLINT is not set when we detect support
> for NMIs.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  arch/arm64/kernel/hyp-stub.S | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> index 2ee18c860f2a..4e0b06467973 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -151,6 +151,18 @@ SYM_CODE_START_LOCAL(__finalise_el2)
>  
>  .Lskip_sme:
>  
> +	// NMIs
> +	__check_override id_aa64pfr1 ID_AA64PFR1_EL1_NMI_SHIFT 4 .Linit_nmi .Lskip_nmi

Err.., What makes sure that x1 contains id_aa64pfr1_el1, as per the
big fat warning at the beginning of the file?? If you have SME, x1
will contain some other junk... Really, this must be written as:

	check_override id_aa64pfr1 ID_AA64PFR1_EL1_NMI_SHIFT .Linit_nmi .Lskip_nmi

> +.Linit_nmi:
> +	mrs	x1, id_aa64mmfr1_el1		// HCRX_EL2 present?
> +	ubfx	x1, x1, #ID_AA64MMFR1_EL1_HCX_SHIFT, #4
> +	cbz	x1, .Lskip_nmi
> +
> +	mrs_s	x1, SYS_HCRX_EL2
> +	and	x1, x1, #~HCRX_EL2_TALLINT_MASK	// Don't trap ALLINT

A nicer way of writing this is:

	bic	x1, x1, #HCRX_EL2_TALLINT_MASK

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-12-05 17:50 UTC|newest]

Thread overview: 96+ 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 ` Mark Brown
2022-11-12 15:16 ` [PATCH v2 01/14] arm64/booting: Document boot requirements " Mark Brown
2022-11-12 15:16   ` 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   ` Mark Brown
2022-11-12 15:16 ` [PATCH v2 03/14] arm64/sysreg: Add definition of ISR_EL1 Mark Brown
2022-11-12 15:16   ` Mark Brown
2022-12-05 16:45   ` Marc Zyngier
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
2022-11-12 15:16   ` Mark Brown
2022-12-05 16:38   ` Marc Zyngier
2022-12-05 16:38     ` Marc Zyngier
2022-12-05 17:11     ` Mark Brown
2022-12-05 17:11       ` Mark Brown
2022-12-07 19:18       ` Marc Zyngier
2022-12-07 19:18         ` Marc Zyngier
2022-12-07 19:42         ` Mark Brown
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
2022-11-12 15:16   ` Mark Brown
2022-12-05 17:29   ` Marc Zyngier
2022-12-05 17:29     ` Marc Zyngier
2022-12-05 18:24     ` Mark Brown
2022-12-05 18:24       ` Mark Brown
2022-12-07 19:14       ` Marc Zyngier
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
2022-11-12 15:17   ` Mark Brown
2022-12-05 17:50   ` Marc Zyngier [this message]
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   ` Mark Brown
2022-11-12 15:17 ` [PATCH v2 08/14] arm64/cpufeature: Detect PE support " Mark Brown
2022-11-12 15:17   ` Mark Brown
2022-12-05 18:03   ` Marc Zyngier
2022-12-05 18:03     ` Marc Zyngier
2022-12-05 19:32     ` Mark Brown
2022-12-05 19:32       ` Mark Brown
2022-12-07 19:06       ` Marc Zyngier
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
2022-11-12 15:17   ` Mark Brown
2022-12-05 18:06   ` Marc Zyngier
2022-12-05 18:06     ` Marc Zyngier
2022-12-05 19:03     ` Mark Brown
2022-12-05 19:03       ` Mark Brown
2022-12-07 19:03       ` Marc Zyngier
2022-12-07 19:03         ` Marc Zyngier
2022-12-07 19:33         ` Mark Brown
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
2022-11-12 15:17   ` Mark Brown
2022-12-05 18:47   ` Marc Zyngier
2022-12-05 18:47     ` Marc Zyngier
2022-12-05 20:52     ` Mark Brown
2022-12-05 20:52       ` Mark Brown
2022-12-08 17:19   ` Lorenzo Pieralisi
2022-12-08 17:19     ` Lorenzo Pieralisi
2022-12-12 14:03     ` Mark Brown
2022-12-12 14:03       ` Mark Brown
2022-12-13  8:37       ` Lorenzo Pieralisi
2022-12-13  8:37         ` Lorenzo Pieralisi
2022-12-13 13:15         ` Mark Brown
2022-12-13 13:15           ` Mark Brown
2022-12-15 13:32           ` Marc Zyngier
2022-12-15 13:32             ` Marc Zyngier
2022-12-12 14:40   ` Mark Rutland
2022-12-12 14:40     ` Mark Rutland
2022-12-15 13:21     ` Mark Brown
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   ` Mark Brown
2022-11-12 15:17 ` [PATCH v2 12/14] arm64/nmi: Add handling of superpriority interrupts as NMIs Mark Brown
2022-11-12 15:17   ` Mark Brown
2022-12-07 11:03   ` Marc Zyngier
2022-12-07 11:03     ` Marc Zyngier
2022-12-07 13:24     ` Mark Brown
2022-12-07 13:24       ` Mark Brown
2022-12-07 18:57       ` Marc Zyngier
2022-12-07 18:57         ` Marc Zyngier
2022-12-07 19:15         ` Mark Brown
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   ` Mark Brown
2022-11-12 15:17 ` [PATCH v2 14/14] irqchip/gic-v3: Implement FEAT_GICv3_NMI support Mark Brown
2022-11-12 15:17   ` Mark Brown
2022-12-07 15:20   ` Marc Zyngier
2022-12-07 15:20     ` Marc Zyngier
2022-12-02 18:42 ` [PATCH v2 00/14] arm64/nmi: Support for FEAT_NMI Marc Zyngier
2022-12-02 18:42   ` Marc Zyngier
2022-12-03  8:25   ` Lorenzo Pieralisi
2022-12-03  8:25     ` Lorenzo Pieralisi
2022-12-03  9:45     ` Marc Zyngier
2022-12-03  9:45       ` Marc Zyngier

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