Commit 6b7982fe authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Marc Zyngier
Browse files

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: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1628744994-16623-5-git-send-email-anshuman.khandual@arm.com
parent bf249d9e

arch/arm64/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/arm64/kvm/arm.c

+1 −15
Original line number Diff line number Diff line
@@ -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;

arch/arm64/kvm/guest.c

+2 −2
Original line number Diff line number Diff line
@@ -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;