Commit 5346f7e1 authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

KVM: arm64: Always return generic v8 as the preferred target 



Userspace selecting an implementation-specific vCPU target has been
completely useless for a very long time. Let's go whole hog and start
returning the generic v8 target across all implementations as the
preferred target.

Uphold the pre-existing behavior by tolerating either the generic target
or an implementation-specific target if the vCPU happens to be running
on one of the lucky few parts.

Acked-by: default avatarZenghui Yu <yuzenghui@huawei.com>
Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230710193140.1706399-5-oliver.upton@linux.dev
parent ef984060

arch/arm64/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -898,7 +898,6 @@ struct kvm_vcpu_stat { 
	u64 exits;

};



void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);

unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);

int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);

int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);

arch/arm64/kvm/arm.c

+5 −4
Original line number Diff line number Diff line
@@ -1250,7 +1250,8 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, 
{

	int ret;



	if (init->target != kvm_target_cpu())

	if (init->target != KVM_ARM_TARGET_GENERIC_V8 &&

	    init->target != kvm_target_cpu())

		return -EINVAL;



	ret = kvm_vcpu_init_check_features(vcpu, init);
@@ -1585,9 +1586,9 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) 
		return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr);

	}

	case KVM_ARM_PREFERRED_TARGET: {

		struct kvm_vcpu_init init;



		kvm_vcpu_preferred_target(&init);

		struct kvm_vcpu_init init = {

			.target = KVM_ARM_TARGET_GENERIC_V8,

		};



		if (copy_to_user(argp, &init, sizeof(init)))

			return -EFAULT;

arch/arm64/kvm/guest.c

+0 −15
Original line number Diff line number Diff line
@@ -884,21 +884,6 @@ u32 __attribute_const__ kvm_target_cpu(void) 
	return KVM_ARM_TARGET_GENERIC_V8;

}



void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)

{

	u32 target = kvm_target_cpu();



	memset(init, 0, sizeof(*init));



	/*

	 * For now, we don't return any features.

	 * In future, we might use features to return target

	 * specific features available for the preferred

	 * target type.

	 */

	init->target = (__u32)target;

}



int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)

{

	return -EINVAL;