Re: [PATCH v2 13/26] KVM: arm64: Restructure FGT register switching

From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Eric Auger <eric.auger@redhat.com>,
	Mark Brown <broonie@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Will Deacon <will@kernel.org>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Andre Przywara <andre.przywara@arm.com>,
	Chase Conklin <chase.conklin@arm.com>,
	Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>,
	Darren Hart <darren@os.amperecomputing.com>,
	Miguel Luis <miguel.luis@oracle.com>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH v2 13/26] KVM: arm64: Restructure FGT register switching
Date: Fri, 28 Jul 2023 17:26:52 +0000	[thread overview]
Message-ID: <ZMP6XBfPrgKMQ/ik@linux.dev> (raw)
In-Reply-To: <20230728082952.959212-14-maz@kernel.org>

Hey Marc,

Looks good, just a typo to fix.

On Fri, Jul 28, 2023 at 09:29:39AM +0100, Marc Zyngier wrote:
> As we're about to majorly extend the handling of FGT registers,
> restructure the code to actually save/restore the registers
> as required. This is made easy thanks to the previous addition
> of the EL2 registers, allowing us to use the host context for
> this purpose.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

> -static inline void __activate_traps_hfgxtr(void)
> +static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
>  {
> +	struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
>  	u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0, tmp;
> +	u64 r_val, w_val;
> +
> +	if (!cpus_have_final_cap(ARM64_HAS_FGT))
> +		return;
> +
> +	ctxt_sys_reg(hctxt, HFGRTR_EL2) = read_sysreg_s(SYS_HFGRTR_EL2);
> +	ctxt_sys_reg(hctxt, HFGWTR_EL2) = read_sysreg_s(SYS_HFGWTR_EL2);
>  
>  	if (cpus_have_final_cap(ARM64_SME)) {
>  		tmp = HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK;
> @@ -98,26 +97,31 @@ static inline void __activate_traps_hfgxtr(void)
>  	if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
>  		w_set |= HFGxTR_EL2_TCR_EL1_MASK;
>  
> -	sysreg_clear_set_s(SYS_HFGRTR_EL2, r_clr, r_set);
> -	sysreg_clear_set_s(SYS_HFGWTR_EL2, w_clr, w_set);
> +
> +	/* The default is not to trap amything but ACCDATA_EL1 */

typo: anything

-- 
Thanks,
Oliver

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