Re: [PATCH 02/26] KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h

From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: maz@kernel.org, linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: mark.rutland@arm.com, will@kernel.org, andre.przywara@arm.com,
	christoffer.dall@arm.com, dave.martin@arm.com,
	gcherian@marvell.com, james.morse@arm.com,
	prime.zeng@hisilicon.com, catalin.marinas@arm.com,
	alexandru.elisei@arm.com, jintack@cs.columbia.edu,
	julien.thierry.kdev@gmail.com
Subject: Re: [PATCH 02/26] KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h
Date: Wed, 22 Apr 2020 14:51:02 +0100	[thread overview]
Message-ID: <7bfefbb0-a467-3e43-6e22-466ae7184a1f@arm.com> (raw)
In-Reply-To: <20200422120050.3693593-3-maz@kernel.org>

Hi Marc,

On 04/22/2020 01:00 PM, Marc Zyngier wrote:
> Having __load_guest_stage2 in kvm_hyp.h is quickly going to trigger
> a circular include problem. In order to avoid this, let's move
> it to kvm_mmu.h, where it will be a better fit anyway.
> 
> In the process, drop the __hyp_text annotation, which doesn't help
> as the function is marked as __always_inline.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

> ---
>   arch/arm64/include/asm/kvm_hyp.h | 18 ------------------
>   arch/arm64/include/asm/kvm_mmu.h | 17 +++++++++++++++++
>   2 files changed, 17 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
> index fe57f60f06a89..dcb63bf941057 100644
> --- a/arch/arm64/include/asm/kvm_hyp.h
> +++ b/arch/arm64/include/asm/kvm_hyp.h
> @@ -10,7 +10,6 @@
>   #include <linux/compiler.h>
>   #include <linux/kvm_host.h>
>   #include <asm/alternative.h>
> -#include <asm/kvm_mmu.h>
>   #include <asm/sysreg.h>
>   
>   #define __hyp_text __section(.hyp.text) notrace
> @@ -88,22 +87,5 @@ void deactivate_traps_vhe_put(void);
>   u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
>   void __noreturn __hyp_do_panic(unsigned long, ...);
>   
> -/*
> - * Must be called from hyp code running at EL2 with an updated VTTBR
> - * and interrupts disabled.
> - */
> -static __always_inline void __hyp_text __load_guest_stage2(struct kvm *kvm)
> -{
> -	write_sysreg(kvm->arch.vtcr, vtcr_el2);
> -	write_sysreg(kvm_get_vttbr(kvm), vttbr_el2);
> -
> -	/*
> -	 * ARM errata 1165522 and 1530923 require the actual execution of the
> -	 * above before we can switch to the EL1/EL0 translation regime used by
> -	 * the guest.
> -	 */
> -	asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT_VHE));
> -}
> -
>   #endif /* __ARM64_KVM_HYP_H__ */
>   
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index 30b0e8d6b8953..5ba1310639ec6 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -604,5 +604,22 @@ static __always_inline u64 kvm_get_vttbr(struct kvm *kvm)
>   	return kvm_phys_to_vttbr(baddr) | vmid_field | cnp;
>   }
>   
> +/*
> + * Must be called from hyp code running at EL2 with an updated VTTBR
> + * and interrupts disabled.
> + */
> +static __always_inline void __load_guest_stage2(struct kvm *kvm)
> +{
> +	write_sysreg(kvm->arch.vtcr, vtcr_el2);
> +	write_sysreg(kvm_get_vttbr(kvm), vttbr_el2);
> +
> +	/*
> +	 * ARM erratum 1165522 requires the actual execution of the above

Is it intentional to drop the reference to errata 1530923 ?

Otherwise :

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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