From: Andy Lutomirski <luto@amacapital.net>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: cocci@systeme.lip6.fr,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
mcb30@ipxe.org, Thomas Gleixner <tglx@linutronix.de>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Joerg Roedel <joro@8bytes.org>,
Robert Moore <robert.moore@intel.com>,
Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Xen Devel <xen-devel@lists.xensource.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Jan Beulich <JBeulich@suse.com>, Lv Zheng <lv.zheng@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
long.wanglong@huawei.com, Fengguang Wu <fengguang.wu@intel.com>,
qiuxishi@huawei.com, Borislav Petkov <bp@alien8.de>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
david.e.box@intel.com, X86 ML <x86@kernel.org>,
Ingo
Subject: Re: [PATCH v2 3/3] paravirt: rename paravirt_enabled to paravirt_legacy
Date: Fri, 5 Feb 2016 23:11:34 -0800 [thread overview]
Message-ID: <CALCETrU3DaqUeo-n2dV_UmeAcTEV2dQRtxyb-atMP6WFDDif3Q@mail.gmail.com> (raw)
In-Reply-To: <1454733014-15237-4-git-send-email-mcgrof@kernel.org>
On Feb 5, 2016 8:30 PM, "Luis R. Rodriguez" <mcgrof@kernel.org> wrote:
>
> paravirt_enabled conveys the idea that if this is set or if
> paravirt_enabled() returns true you are in a paravirtualized
> environment. This is not true by any means, and left as-is
> is just causing confusion and is prone to be misused and abused.
>
> This primitive is really only useful to determine if you have a
> paravirtualization hypervisor that supports legacy paravirtualized
> guests. At run time, this tells us if we've booted into a Linux guest
> with support for legacy devices and features.
>
> To avoid further issues with semantics on this we loosely borrow
> the definition of "legacy" from both the ACPI 5.2.9.3 "IA-PC Boot
> Architecture Flags" section and the PC 2001 definition in the PC
> Systems design guide [0]:
>
> paravirt_legacy() is true if this hypervisor supports legacy
> x86 paravirtualized guests.
This needs to be far more concrete. I'm reasonably well versed in x86
details relevant to kernels ans I have *no clue* what your semantics
mean.
> +/**
> + * struct pv_info - paravirt hypervisor information
> + *
> + * @supports_x86_legacy: true if this hypervisor supports legacy x86
> + * paravirtualized guests. The definition of legacy here adheres
> + * *loosely* to both the notion of legacy in the ACPI 5.2.9.3 "IA-PC Boot
> + * Architecture Flags" section and the PC 2001 "legacy free" concept [1]
> + * referred to in the PC System Design Guide [2] [3] on Chapter 3, Page 50
> + * [4]. Legacy x86 guests systems are guest systems which are not "legacy
> + * free" as per the PC 2001 definition, and in the ACPI sense could have
> + * any of the legacy ACPI IA-PC Boot architecture flags set. These are x86
> + * systems with any type of legacy peripherals or requirements.
> + *
> + * Examples of some popular legacy peripherals:
> + *
> + * a) Floppy drive
> + * b) Legacy ports [1] such as such as parallel ports, PS/2 connectors,
> + * serial ports / RS-232, game ports Parallel ATA, and IEEE 1394
> + * c) ISA bus
> + *
> + * Examples of features required to support such type of legacy guests
> + * are the need for APM and a PNP BIOS.
Seriously? I think you just defined every standard native x86 system
as well as QEMU/KVM as "legacy".
Can we just enumerate this crap? I propose:
Xen PV and lguest are paravirt_legacy. Nothing else is
paravirt_legacy. The addition of new paravirt_legacy support is
strongly discouraged.
--Andy
next prev parent reply other threads:[~2016-02-06 7:11 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-06 4:30 [PATCH v2 0/3] paravirt: rebrand paravirt_enabled as paravirt_legacy Luis R. Rodriguez
2016-02-06 4:30 ` [PATCH v2 1/3] paravirt: use bool for paravirt_enabled() and paravirt_has_feature() Luis R. Rodriguez
2016-02-06 4:30 ` [PATCH v2 2/3] paravirt: replace direct access to pv_info.paravirt_enabled Luis R. Rodriguez
2016-02-06 4:30 ` [PATCH v2 3/3] paravirt: rename paravirt_enabled to paravirt_legacy Luis R. Rodriguez
2016-02-06 7:11 ` Andy Lutomirski [this message]
2016-02-06 8:59 ` Luis R. Rodriguez
2016-02-06 20:05 ` Andy Lutomirski
2016-02-06 22:04 ` Borislav Petkov
2016-02-08 15:39 ` Boris Ostrovsky
2016-02-08 15:55 ` Borislav Petkov
2016-02-08 16:05 ` [Xen-devel] " Andrew Cooper
2016-02-08 16:12 ` Boris Ostrovsky
2016-02-08 16:26 ` Andrew Cooper
2016-02-08 16:31 ` Boris Ostrovsky
2016-02-08 16:32 ` Andrew Cooper
2016-02-08 16:35 ` Borislav Petkov
2016-02-08 16:38 ` Andrew Cooper
2016-02-08 16:45 ` Borislav Petkov
2016-02-08 16:52 ` Boris Ostrovsky
2016-02-08 20:45 ` Boris Ostrovsky
2016-02-08 21:06 ` Borislav Petkov
2016-02-08 16:53 ` Andrew Cooper
2016-02-08 17:13 ` Borislav Petkov
2016-02-09 6:22 ` Luis R. Rodriguez
2016-02-08 16:41 ` Boris Ostrovsky
2016-02-08 16:52 ` Borislav Petkov
2016-02-08 15:31 ` Boris Ostrovsky
2016-02-08 15:46 ` Borislav Petkov
2016-02-09 6:59 ` Luis R. Rodriguez
2016-02-08 21:04 ` Andy Lutomirski
2016-02-09 7:06 ` Luis R. Rodriguez
2016-02-17 20:07 ` Luis R. Rodriguez
2016-02-17 20:49 ` Borislav Petkov
2016-02-17 21:12 ` Luis R. Rodriguez
2016-02-17 21:21 ` Boris Ostrovsky
2016-02-17 22:03 ` Borislav Petkov
2016-02-17 22:18 ` Andy Lutomirski
2016-02-17 22:39 ` Boris Ostrovsky
2016-02-17 23:39 ` Borislav Petkov
2016-02-17 22:19 ` Boris Ostrovsky
2016-02-17 22:35 ` Luis R. Rodriguez
2016-02-09 6:41 ` Luis R. Rodriguez
2016-02-08 21:49 ` Boris Ostrovsky
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