linux-kernel - Re: [PATCH v2] x86/bhyve: Detect FreeBSD Bhyve hypervisor

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Message-ID: <aJ4iwpQOnrc_iN8Y@lx-t490>
Date: Thu, 14 Aug 2025 19:54:10 +0200
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: David Woodhouse <dwmw2@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	David Woodhouse <dwmw@...zon.co.uk>, linux-kernel@...r.kernel.org,
	Konstantin Belousov <kib@....kiev.ua>,
	John Baldwin <jhb@...ebsd.org>,
	"<cperciva@...snap.com>" <cperciva@...snap.com>
Subject: Re: [PATCH v2] x86/bhyve: Detect FreeBSD Bhyve hypervisor

On Thu, 14 Aug 2025, David Woodhouse wrote:
> +
> +static uint32_t bhyve_cpuid_base;
> +static uint32_t bhyve_cpuid_max;
> +
...
> +static uint32_t __init bhyve_detect(void)
> +{
> +	if (boot_cpu_data.cpuid_level < 0 ||
> +            !cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
> +                return 0;
> +
> +	bhyve_cpuid_base = cpuid_base_hypervisor("bhyve bhyve ", 0);
> +	if (!bhyve_cpuid_base)
> +		return 0;
> +
> +	bhyve_cpuid_max = cpuid_eax(bhyve_cpuid_max);
> +
                                                ^^^

You're using CPUID(0x0) by mistake here ;)

I guess you just meant:

	bhyve_cpuid_max = cpuid_eax(bhyve_cpuid_base);

Thanks!
Ahmed