linux-kernel - Re: [PATCH v8 1/7] xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and CONFIG_XEN

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Date:   Thu, 6 Dec 2018 23:11:41 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Maran Wilson <maran.wilson@...cle.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
        kvm@...r.kernel.org, jgross@...e.com
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        boris.ostrovsky@...cle.com, jpoimboe@...hat.com,
        kirill.shutemov@...ux.intel.com, bp@...e.de,
        thomas.lendacky@....com, luto@...nel.org,
        dave.hansen@...ux.intel.com, roger.pau@...rix.com,
        rkrcmar@...hat.com, rdunlap@...radead.org
Subject: Re: [PATCH v8 1/7] xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and
 CONFIG_XEN_PVH

On 06/12/18 07:04, Maran Wilson wrote:
> +config PVH
> +	bool "Support for running PVH guests"
> +	---help---
> +	  This option enables the PVH entry point for guest virtual machines
> +	  as specified in the x86/HVM direct boot ABI.
> +

IIUC this breaks "normal" bzImage boot, so we should have something like

	The resulting kernel will not boot with most x86 boot loaders
	such as GRUB or SYSLINUX.  Unless you plan to start the kernel
	using QEMU or Xen, you probably want to say N here.

and also

	depends on !EFI

because even though in principle it would be possible to write a PVH
loader for UEFI, PVH's start info does not support the EFI handover
protocol.

Paolo