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From: Marc Zyngier <maz@kernel.org>
To: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>,
	kernel-team@android.com
Subject: Re: [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
Date: Tue, 10 Nov 2020 09:33:25 +0000	[thread overview]
Message-ID: <1df601250710b1fdef1e9089c33c5850@kernel.org> (raw)
In-Reply-To: <20201109213023.15092-4-will@kernel.org>

On 2020-11-09 21:30, Will Deacon wrote:
> If a vCPU tries to run 32-bit code on a system with mismatched support

nit: s/tries to run/is caught running/

> at EL0, then we should kill it.
> 
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
>  arch/arm64/kvm/arm.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 5750ec34960e..d322ac0f4a8e 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -633,6 +633,15 @@ static void check_vcpu_requests(struct kvm_vcpu 
> *vcpu)
>  	}
>  }
> 
> +static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
> +{
> +	if (likely(!vcpu_mode_is_32bit(vcpu)))
> +		return false;
> +
> +	return !system_supports_32bit_el0() ||
> +		static_branch_unlikely(&arm64_mismatched_32bit_el0);
> +}
> +
>  /**
>   * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute 
> guest code
>   * @vcpu:	The VCPU pointer
> @@ -816,7 +825,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  		 * with the asymmetric AArch32 case), return to userspace with
>  		 * a fatal error.
>  		 */
> -		if (!system_supports_32bit_el0() && vcpu_mode_is_32bit(vcpu)) {
> +		if (vcpu_mode_is_bad_32bit(vcpu)) {
>  			/*
>  			 * As we have caught the guest red-handed, decide that
>  			 * it isn't fit for purpose anymore by making the vcpu

Acked-by: Marc Zyngier <maz@kernel.org>

         M.
-- 
Jazz is not dead. It just smells funny...

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Will Deacon <will@kernel.org>
Cc: linux-arch@vger.kernel.org, kernel-team@android.com,
	Quentin Perret <qperret@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
Date: Tue, 10 Nov 2020 09:33:25 +0000	[thread overview]
Message-ID: <1df601250710b1fdef1e9089c33c5850@kernel.org> (raw)
In-Reply-To: <20201109213023.15092-4-will@kernel.org>

On 2020-11-09 21:30, Will Deacon wrote:
> If a vCPU tries to run 32-bit code on a system with mismatched support

nit: s/tries to run/is caught running/

> at EL0, then we should kill it.
> 
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
>  arch/arm64/kvm/arm.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 5750ec34960e..d322ac0f4a8e 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -633,6 +633,15 @@ static void check_vcpu_requests(struct kvm_vcpu 
> *vcpu)
>  	}
>  }
> 
> +static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
> +{
> +	if (likely(!vcpu_mode_is_32bit(vcpu)))
> +		return false;
> +
> +	return !system_supports_32bit_el0() ||
> +		static_branch_unlikely(&arm64_mismatched_32bit_el0);
> +}
> +
>  /**
>   * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute 
> guest code
>   * @vcpu:	The VCPU pointer
> @@ -816,7 +825,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  		 * with the asymmetric AArch32 case), return to userspace with
>  		 * a fatal error.
>  		 */
> -		if (!system_supports_32bit_el0() && vcpu_mode_is_32bit(vcpu)) {
> +		if (vcpu_mode_is_bad_32bit(vcpu)) {
>  			/*
>  			 * As we have caught the guest red-handed, decide that
>  			 * it isn't fit for purpose anymore by making the vcpu

Acked-by: Marc Zyngier <maz@kernel.org>

         M.
-- 
Jazz is not dead. It just smells funny...

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

  reply	other threads:[~2020-11-10  9:33 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 21:30 [PATCH v2 0/6] An alternative series for asymmetric AArch32 systems Will Deacon
2020-11-09 21:30 ` Will Deacon
2020-11-09 21:30 ` [PATCH v2 1/6] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-09 21:30 ` [PATCH v2 2/6] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-11 19:10   ` Catalin Marinas
2020-11-11 19:10     ` Catalin Marinas
2020-11-13  9:36     ` Will Deacon
2020-11-13  9:36       ` Will Deacon
2020-11-13 10:26       ` Catalin Marinas
2020-11-13 10:26         ` Catalin Marinas
2020-11-09 21:30 ` [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-10  9:33   ` Marc Zyngier [this message]
2020-11-10  9:33     ` Marc Zyngier
2020-11-09 21:30 ` [PATCH v2 4/6] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-09 21:30 ` [PATCH v2 5/6] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2020-11-09 21:30   ` Will Deacon
2020-11-10  7:04   ` Greg Kroah-Hartman
2020-11-10  7:04     ` Greg Kroah-Hartman
2020-11-10  9:28     ` Catalin Marinas
2020-11-10  9:28       ` Catalin Marinas
2020-11-10  9:36       ` Greg Kroah-Hartman
2020-11-10  9:36         ` Greg Kroah-Hartman
2020-11-10  9:53         ` Marc Zyngier
2020-11-10  9:53           ` Marc Zyngier
2020-11-10 10:10           ` Greg Kroah-Hartman
2020-11-10 10:10             ` Greg Kroah-Hartman
2020-11-10 10:46             ` Marc Zyngier
2020-11-10 10:46               ` Marc Zyngier
2020-11-10 10:57         ` Catalin Marinas
2020-11-10 10:57           ` Catalin Marinas
2020-11-09 21:30 ` [PATCH v2 6/6] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-11-09 21:30   ` Will Deacon

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