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 09/14] KVM: arm64: Hide FEAT_NMI from guests
Date: Mon, 05 Dec 2022 18:06:24 +0000 [thread overview]
Message-ID: <86pmcxlo7z.wl-maz@kernel.org> (raw)
In-Reply-To: <20221112151708.175147-10-broonie@kernel.org>
On Sat, 12 Nov 2022 15:17:03 +0000,
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?
>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
> arch/arm64/kvm/hyp/include/hyp/switch.h | 6 ++++++
> arch/arm64/kvm/sys_regs.c | 1 +
> 2 files changed, 7 insertions(+)
>
> diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
> index 6cbbb6c02f66..89e78c4e5cce 100644
> --- a/arch/arm64/kvm/hyp/include/hyp/switch.h
> +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
> @@ -85,6 +85,9 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
> write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
> }
>
> + if (cpus_have_final_cap(ARM64_HAS_NMI))
> + sysreg_clear_set_s(SYS_HCRX_EL2, 0, HCRX_EL2_TALLINT);
> +
Crucially, this is missing a handler for the trap, resulting in a
large splat once a guest accesses ALLINT.
M.
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2022-12-05 18:07 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 [this message]
2022-12-05 19:03 ` Mark Brown
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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