From: Will Deacon <will@kernel.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] KVM: arm64: Drop check_kvm_target_cpu() based percpu probe
Date: Tue, 10 Aug 2021 14:28:22 +0100 [thread overview]
Message-ID: <20210810132822.GC2946@willie-the-truck> (raw)
In-Reply-To: <1628578961-29097-4-git-send-email-anshuman.khandual@arm.com>
On Tue, Aug 10, 2021 at 12:32:39PM +0530, Anshuman Khandual wrote:
> kvm_target_cpu() never returns a negative error code, so check_kvm_target()
> would never have 'ret' filled with a negative error code. Hence the percpu
> probe via check_kvm_target_cpu() does not make sense as its never going to
> find an unsupported CPU, forcing kvm_arch_init() to exit early. Hence lets
> just drop this percpu probe (and also check_kvm_target_cpu()) altogether.
>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: James Morse <james.morse@arm.com>
> Cc: Alexandru Elisei <alexandru.elisei@arm.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: kvmarm@lists.cs.columbia.edu
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm64/kvm/arm.c | 14 --------------
> 1 file changed, 14 deletions(-)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 19560e457c11..16f93678c17e 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -2010,11 +2010,6 @@ static int finalize_hyp_mode(void)
> return 0;
> }
>
> -static void check_kvm_target_cpu(void *ret)
> -{
> - *(int *)ret = kvm_target_cpu();
> -}
> -
> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
> {
> struct kvm_vcpu *vcpu;
> @@ -2074,7 +2069,6 @@ void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *cons)
> int kvm_arch_init(void *opaque)
> {
> int err;
> - int ret, cpu;
> bool in_hyp_mode;
>
> if (!is_hyp_mode_available()) {
> @@ -2089,14 +2083,6 @@ int kvm_arch_init(void *opaque)
> kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \
> "Only trusted guests should be used on this system.\n");
>
> - for_each_online_cpu(cpu) {
> - smp_call_function_single(cpu, check_kvm_target_cpu, &ret, 1);
> - if (ret < 0) {
> - kvm_err("Error, CPU %d not supported!\n", cpu);
> - return -ENODEV;
> - }
> - }
Looks like kvm_target_cpu() *could* return an error at one time of day (at
least on 32-bit), but agreed that this checking is no longer needed:
Acked-by: Will Deacon <will@kernel.org>
Perhaps it's worth making the return type of kvm_target_cpu() a u32 to
make it a bit more explicit that you shouldn't be returning an error code
there?
Will
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next prev parent reply other threads:[~2021-08-10 13:31 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-10 7:02 [PATCH 0/5] KVM: arm64: General cleanups Anshuman Khandual
2021-08-10 7:02 ` [PATCH 1/5] KVM: arm64: Drop direct PAGE_[SHIFT|SIZE] usage as page size Anshuman Khandual
2021-08-10 13:20 ` Will Deacon
2021-08-11 5:32 ` Anshuman Khandual
2021-08-10 13:33 ` Marc Zyngier
2021-08-11 5:34 ` Anshuman Khandual
2021-08-11 8:11 ` Marc Zyngier
2021-08-11 9:37 ` Anshuman Khandual
2021-08-11 10:13 ` Marc Zyngier
2021-08-10 7:02 ` [PATCH 2/5] KVM: arm64: Drop init_common_resources() Anshuman Khandual
2021-08-10 13:21 ` Will Deacon
2021-08-10 15:11 ` Anshuman Khandual
2021-08-10 7:02 ` [PATCH 3/5] KVM: arm64: Drop check_kvm_target_cpu() based percpu probe Anshuman Khandual
2021-08-10 13:28 ` Will Deacon [this message]
2021-08-11 5:54 ` Anshuman Khandual
2021-08-10 7:02 ` [PATCH 4/5] KVM: arm64: Drop unused REQUIRES_VIRT Anshuman Khandual
2021-08-10 7:02 ` [PATCH 5/5] KVM: arm64: Define KVM_PHYS_SHIFT_MIN Anshuman Khandual
2021-08-10 13:29 ` Marc Zyngier
2021-08-10 15:19 ` Anshuman Khandual
2021-08-10 15:32 ` Marc Zyngier
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