Re: [PATCH v4 05/14] KVM: arm64: Initialize feature id registers for protected VMs

[Oliver Upton <oliver.upton@linux.dev>]

Hi Fuad,

On Mon, Dec 02, 2024 at 03:47:32PM +0000, Fuad Tabba wrote:
> +/*
> + * Initializes feature registers for protected vms.
> + */
> +void kvm_init_pvm_id_regs(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	struct kvm_arch *ka = &kvm->arch;
> +	u32 r;
> +

Can you add an assertion that this is called while holding the
vm_table_lock? Otherwise it isn't clear why its safe to initialize
per-VM state.

> +	if (test_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags))
> +		return;
> +
> +	/*
> +	 * Initialize only AArch64 id registers since AArch32 isn't supported
> +	 * for protected VMs.
> +	 */
> +	for (r = sys_reg(3, 0, 0, 4, 0); r <= sys_reg(3, 0, 0, 7, 7); r += sys_reg(0, 0, 0, 0, 1))
> +		ka->id_regs[IDREG_IDX(r)] = pvm_calc_id_reg(vcpu, r);
> +
> +	set_bit(KVM_ARCH_FLAG_ID_REGS_INITIALIZED, &kvm->arch.flags);
> +}
> +
>  /*
>   * Checks that the sysreg table is unique and in-order.
>   *
> -- 
> 2.47.0.338.g60cca15819-goog
> 

-- 
Thanks,
Oliver