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Date: Tue, 10 Feb 2026 09:26:20 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Alejandro Vallejo Cc: xen-devel@lists.xenproject.org, Jan Beulich , Andrew Cooper , Jason Andryuk Subject: Re: [PATCH 02/12] x86: Add more granularity to the vendors in Kconfig Message-ID: References: <20260206161539.209922-1-alejandro.garciavallejo@amd.com> <20260206161539.209922-3-alejandro.garciavallejo@amd.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260206161539.209922-3-alejandro.garciavallejo@amd.com> X-ClientProxiedBy: MA3P292CA0022.ESPP292.PROD.OUTLOOK.COM (2603:10a6:250:47::17) To CH7PR03MB7860.namprd03.prod.outlook.com (2603:10b6:610:24e::14) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH7PR03MB7860:EE_|DS7PR03MB5526:EE_ X-MS-Office365-Filtering-Correlation-Id: 8f792871-5b06-4b1a-1a39-08de687e1394 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014|7053199007; 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A lot of statics go away and a lot more inlining will be allowed. > > A prerequisite for such optimisation is to expand Kconfig to have the > full set of vendors. Adds Hygon, Centaur, Shanghai and the unknown-vendor > path. Have Hygon select AMD, and Centaur|Shanghai select Intel. > > Not a functional change. > > Signed-off-by: Alejandro Vallejo > --- > rfc -> v1: > * s/depends on/select/ > * s/UNKNOWN_CPU/UNKNOWN_CPU_VENDOR/ > * Removed "if unsure, say Y" > --- > xen/arch/x86/Kconfig.cpu | 43 +++++++++++++++++++++++++++++++++++++++ > xen/arch/x86/cpu/Makefile | 6 +++--- > 2 files changed, 46 insertions(+), 3 deletions(-) > > diff --git a/xen/arch/x86/Kconfig.cpu b/xen/arch/x86/Kconfig.cpu > index 5fb18db1aa..f895cfe97a 100644 > --- a/xen/arch/x86/Kconfig.cpu > +++ b/xen/arch/x86/Kconfig.cpu > @@ -19,4 +19,47 @@ config INTEL > May be turned off in builds targetting other vendors. Otherwise, > must be enabled for Xen to work suitably on Intel platforms. > > +config HYGON > + bool "Support Hygon CPUs" > + select AMD > + default y > + help > + Detection, tunings and quirks for Hygon platforms. > + > + May be turned off in builds targetting other vendors. Otherwise, > + must be enabled for Xen to work suitably on Hygon platforms. > + > + > +config CENTAUR > + bool "Support Centaur CPUs" > + select INTEL > + default y > + help > + Detection, tunings and quirks for Centaur platforms. > + > + May be turned off in builds targetting other vendors. Otherwise, > + must be enabled for Xen to work suitably on Centaur platforms. > + > +config SHANGHAI > + bool "Support Shanghai CPUs" > + select INTEL > + default y > + help > + Detection, tunings and quirks for Shanghai platforms. > + > + May be turned off in builds targetting other vendors. Otherwise, > + must be enabled for Xen to work suitably on Shanghai platforms. > + > +config UNKNOWN_CPU_VENDOR > + bool "Support unknown CPU vendors" > + default y > + help > + This option prevents a panic on boot when the host CPU vendor isn't > + supported by going into a legacy compatibility mode and not applying > + any relevant tunings or quirks. > + > + Not selecting this options while selecting multiple vendors doesn't have > + any major effect on code size, but selecting a single vendor with this > + option cleared produces a much smaller build. > + > endmenu > diff --git a/xen/arch/x86/cpu/Makefile b/xen/arch/x86/cpu/Makefile > index 7cfe28b7ec..84b060aa41 100644 > --- a/xen/arch/x86/cpu/Makefile > +++ b/xen/arch/x86/cpu/Makefile > @@ -3,13 +3,13 @@ obj-y += microcode/ > obj-y += mtrr/ > > obj-y += amd.o > -obj-y += centaur.o > +obj-$(CONFIG_CENTAUR) += centaur.o Maybe I'm missing some context here, but I think this would break the build? cpu/centaur.c exports centaur_cpu_dev which is referenced from cpu/common.c, and I don't see you making that reference in cpu/common.c conditional to CONFIG_CENTAUR being defined? I think the same applies to Hygon and Shanghai. Thanks, Roger.