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.

While here, this also changes kvm_target_cpu() return type to a u32, making
it explicit that an error code will not be returned from this function.

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
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1628744994-16623-5-git-send-email-anshuman.khandual@arm.com

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 41911585ae0cfa3db73e6c67b78e88e0e781a118..26bbd84a02defe314d4f6cf97e4107645f5a02fb 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -66,7 +66,7 @@ DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 extern unsigned int kvm_sve_max_vl;
 int kvm_arm_init_sve(void);
 
-int __attribute_const__ kvm_target_cpu(void);
+u32 __attribute_const__ kvm_target_cpu(void);
 int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
 void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu);
 

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 19560e457c111a0ec764dd61f3af1eee5094116a..ee9b1166f330b00d40001a7517d56e1c69a3993e 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1035,7 +1035,7 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
                               const struct kvm_vcpu_init *init)
 {
        unsigned int i, ret;
-       int phys_target = kvm_target_cpu();
+       u32 phys_target = kvm_target_cpu();
 
        if (init->target != phys_target)
                return -EINVAL;
@@ -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;

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 1dfb83578277091f539cc986852405a1178983b7..8ce850fa7b4960fdd524df086666b1a404abb622 100644 (file)
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -842,7 +842,7 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
        return 0;
 }
 
-int __attribute_const__ kvm_target_cpu(void)
+u32 __attribute_const__ kvm_target_cpu(void)
 {
        unsigned long implementor = read_cpuid_implementor();
        unsigned long part_number = read_cpuid_part_number();
@@ -874,7 +874,7 @@ int __attribute_const__ kvm_target_cpu(void)
 
 int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
 {
-       int target = kvm_target_cpu();
+       u32 target = kvm_target_cpu();
 
        if (target < 0)
                return -ENODEV;