linux-kernel - [PATCH 3/5] KVM: arm64: Drop check_kvm_target

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Date:   Tue, 10 Aug 2021 12:32:39 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     Anshuman Khandual <anshuman.khandual@....com>,
        Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/5] KVM: arm64: Drop check_kvm_target_cpu() based percpu probe

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@...nel.org>
Cc: James Morse <james.morse@....com>
Cc: Alexandru Elisei <alexandru.elisei@....com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: kvmarm@...ts.cs.columbia.edu
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....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;
-		}
-	}
-
 	err = kvm_set_ipa_limit();
 	if (err)
 		return err;
-- 
2.20.1