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    SubjectRE: [Xen-devel] [PATCH 1/3] PAD helper for native and paravirt platform
    Date
    Konrad Rzeszutek Wilk wrote:
    > On Fri, Feb 17, 2012 at 09:29:09AM -0500, Konrad Rzeszutek Wilk wrote:
    >> On Fri, Feb 17, 2012 at 08:56:43AM +0000, Liu, Jinsong wrote:
    >>>> From f66a2df1392bbe69426387657a220177be50d58a Mon Sep 17 00:00:00
    >>>> 2001
    >>> From: Liu, Jinsong <jinsong.liu@intel.com>
    >>> Date: Fri, 10 Feb 2012 20:32:50 +0800
    >>> Subject: [PATCH 1/3] PAD helper for native and paravirt platform
    >>>
    >>> This patch is PAD (Processor Aggregator Device) helper.
    >>> It provides a native interface for natvie platform, and a template
    >>> for paravirt platform, so that os can implicitly hook to proper ops
    >>> accordingly.
    >>> The paravirt template will further redirect to Xen pv ops in later
    >>> patch for Xen core parking.
    >>
    >> You need to CC the ACPI maintainer and the acpi mailing on this
    >> patch. I did that for you in the CC.
    >>
    >>
    >>>
    >>> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com> ---
    >>> arch/x86/include/asm/paravirt.h | 10 +++++
    >>> arch/x86/include/asm/paravirt_types.h | 7 ++++
    >>> arch/x86/kernel/paravirt.c | 9 +++++
    >>> drivers/acpi/acpi_pad.c | 15 +++-----
    >>> include/acpi/acpi_pad.h | 61
    >>> +++++++++++++++++++++++++++++++++ 5 files changed, 93
    >>> insertions(+), 9 deletions(-) create mode 100644
    >>> include/acpi/acpi_pad.h
    >>>
    >>> diff --git a/arch/x86/include/asm/paravirt.h
    >>> b/arch/x86/include/asm/paravirt.h
    >>> index a7d2db9..02e6df0 100644
    >>> --- a/arch/x86/include/asm/paravirt.h
    >>> +++ b/arch/x86/include/asm/paravirt.h
    >>> @@ -54,6 +54,16 @@ static inline unsigned long read_cr0(void)
    >>> return PVOP_CALL0(unsigned long, pv_cpu_ops.read_cr0); }
    >>>
    >>> +static inline int __acpi_pad_init(void)
    >>> +{
    >>> + return PVOP_CALL0(int, pv_pad_ops.acpi_pad_init); +}
    >>> +
    >>> +static inline void __acpi_pad_exit(void)
    >>> +{
    >>> + PVOP_VCALL0(pv_pad_ops.acpi_pad_exit);
    >>> +}
    >>> +
    >>> static inline void write_cr0(unsigned long x)
    >>> {
    >>> PVOP_VCALL1(pv_cpu_ops.write_cr0, x);
    >>> diff --git a/arch/x86/include/asm/paravirt_types.h
    >>> b/arch/x86/include/asm/paravirt_types.h index 8e8b9a4..61e20de
    >>> 100644 --- a/arch/x86/include/asm/paravirt_types.h +++
    >>> b/arch/x86/include/asm/paravirt_types.h @@ -336,6 +336,11 @@ struct
    >>> pv_lock_ops { void (*spin_unlock)(struct arch_spinlock *lock);
    >>> };
    >>>
    >>> +struct pv_pad_ops {
    >>> + int (*acpi_pad_init)(void);
    >>> + void (*acpi_pad_exit)(void);
    >>> +};
    >>> +
    >
    > Looking at this a bit closer I am not sure why you choose the paravirt
    > interface for this? There is another one - the x86 that could have
    > been
    > choosen. Or introduce a new one that is specific to ACPI.
    >
    > I am curious - what was the reason for using the paravirt interface?
    > I understand it does get the job done, but it seems a bit overkill
    > when something simple could have been used?
    >

    It uses paravirt interface to avoid some code like 'xen_...' in native code path (acpi_pad.c).
    I'm not quite sure what does 'x86' here mean? Adding 2 fields (acpi_pad_init/exit) in arch/x86/xen/enlighten.c --> xen_cpu_ops? seems it's much simpler.

    Thanks,
    Jinsong

    >>> /* This contains all the paravirt structures: we get a convenient
    >>> * number for each function using the offset which we use to
    >>> indicate
    >>> * what to patch. */
    >>> @@ -347,6 +352,7 @@ struct paravirt_patch_template {
    >>> struct pv_apic_ops pv_apic_ops;
    >>> struct pv_mmu_ops pv_mmu_ops;
    >>> struct pv_lock_ops pv_lock_ops;
    >>> + struct pv_pad_ops pv_pad_ops;
    >>> };
    >>>
    >>> extern struct pv_info pv_info;
    >>> @@ -357,6 +363,7 @@ extern struct pv_irq_ops pv_irq_ops;
    >>> extern struct pv_apic_ops pv_apic_ops;
    >>> extern struct pv_mmu_ops pv_mmu_ops;
    >>> extern struct pv_lock_ops pv_lock_ops;
    >>> +extern struct pv_pad_ops pv_pad_ops;
    >>>
    >>> #define PARAVIRT_PATCH(x) \
    >>> (offsetof(struct paravirt_patch_template, x) / sizeof(void *))
    >>> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
    >>> index d90272e..ec778f6 100644
    >>> --- a/arch/x86/kernel/paravirt.c
    >>> +++ b/arch/x86/kernel/paravirt.c
    >>> @@ -38,6 +38,8 @@
    >>> #include <asm/tlbflush.h>
    >>> #include <asm/timer.h>
    >>>
    >>> +#include <acpi/acpi_pad.h>
    >>> +
    >>> /* nop stub */
    >>> void _paravirt_nop(void)
    >>> {
    >>> @@ -132,6 +134,7 @@ static void *get_call_destination(u8 type)
    >>> #ifdef CONFIG_PARAVIRT_SPINLOCKS
    >>> .pv_lock_ops = pv_lock_ops,
    >>> #endif
    >>> + .pv_pad_ops = pv_pad_ops,
    >>> };
    >>> return *((void **)&tmpl + type);
    >>> }
    >>> @@ -480,9 +483,15 @@ struct pv_mmu_ops pv_mmu_ops = {
    >>> .set_fixmap = native_set_fixmap,
    >>> };
    >>>
    >>> +struct pv_pad_ops pv_pad_ops = {
    >>> + .acpi_pad_init = native_acpi_pad_init,
    >>> + .acpi_pad_exit = native_acpi_pad_exit,
    >>> +};
    >>> +
    >>> EXPORT_SYMBOL_GPL(pv_time_ops);
    >>> EXPORT_SYMBOL (pv_cpu_ops);
    >>> EXPORT_SYMBOL (pv_mmu_ops);
    >>> EXPORT_SYMBOL_GPL(pv_apic_ops);
    >>> EXPORT_SYMBOL_GPL(pv_info);
    >>> EXPORT_SYMBOL (pv_irq_ops);
    >>> +EXPORT_SYMBOL_GPL(pv_pad_ops);
    >>> diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
    >>> index a43fa1a..3f0fd27 100644
    >>> --- a/drivers/acpi/acpi_pad.c
    >>> +++ b/drivers/acpi/acpi_pad.c
    >>> @@ -30,6 +30,7 @@
    >>> #include <linux/slab.h>
    >>> #include <acpi/acpi_bus.h>
    >>> #include <acpi/acpi_drivers.h>
    >>> +#include <acpi/acpi_pad.h>
    >>> #include <asm/mwait.h>
    >>>
    >>> #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" @@ -37,14
    >>> +38,14 @@ #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
    >>> static DEFINE_MUTEX(isolated_cpus_lock);
    >>>
    >>> -static unsigned long power_saving_mwait_eax;
    >>> +unsigned long power_saving_mwait_eax;
    >>>
    >>> static unsigned char tsc_detected_unstable;
    >>> static unsigned char tsc_marked_unstable;
    >>> static unsigned char lapic_detected_unstable;
    >>> static unsigned char lapic_marked_unstable;
    >>>
    >>> -static void power_saving_mwait_init(void)
    >>> +void power_saving_mwait_init(void)
    >>> {
    >>> unsigned int eax, ebx, ecx, edx;
    >>> unsigned int highest_cstate = 0;
    >>> @@ -500,7 +501,7 @@ static const struct acpi_device_id
    >>> pad_device_ids[] = { }; MODULE_DEVICE_TABLE(acpi, pad_device_ids);
    >>>
    >>> -static struct acpi_driver acpi_pad_driver = {
    >>> +struct acpi_driver acpi_pad_driver = {
    >>> .name = "processor_aggregator",
    >>> .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
    >>> .ids = pad_device_ids,
    >>> @@ -512,16 +513,12 @@ static struct acpi_driver acpi_pad_driver = {
    >>>
    >>> static int __init acpi_pad_init(void)
    >>> {
    >>> - power_saving_mwait_init();
    >>> - if (power_saving_mwait_eax == 0)
    >>> - return -EINVAL;
    >>> -
    >>> - return acpi_bus_register_driver(&acpi_pad_driver); + return
    >>> __acpi_pad_init(); }
    >>>
    >>> static void __exit acpi_pad_exit(void)
    >>> {
    >>> - acpi_bus_unregister_driver(&acpi_pad_driver);
    >>> + __acpi_pad_exit();
    >>> }
    >>>
    >>> module_init(acpi_pad_init);
    >>> diff --git a/include/acpi/acpi_pad.h b/include/acpi/acpi_pad.h
    >>> new file mode 100644
    >>> index 0000000..1a1471d
    >>> --- /dev/null
    >>> +++ b/include/acpi/acpi_pad.h
    >>> @@ -0,0 +1,61 @@
    >>> +/*
    >>> + * acpi_pad.h - pad device helper for native and paravirt
    >>> platform + * + * Copyright (C) 2012, Intel Corporation.
    >>> + * Author: Liu, Jinsong <jinsong.liu@intel.com> + *
    >>> + * This program is free software; you can redistribute it and/or
    >>> modify + * it under the terms of the GNU General Public License as
    >>> published by + * the Free Software Foundation; either version 2 of
    >>> the License, or (at + * your option) any later version.
    >>> + *
    >>> + * This program is distributed in the hope that it will be
    >>> useful, but + * WITHOUT ANY WARRANTY; without even the implied
    >>> warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR
    >>> PURPOSE. See the GNU + * General Public License for more details.
    >>> + */
    >>> +
    >>> +#ifndef __ACPI_PAD_H__
    >>> +#define __ACPI_PAD_H__
    >>> +
    >>> +#include <acpi/acpi_bus.h>
    >>> +
    >>> +extern unsigned long power_saving_mwait_eax;
    >>> +extern struct acpi_driver acpi_pad_driver;
    >>> +extern void power_saving_mwait_init(void);
    >>> +
    >>> +static inline int native_acpi_pad_init(void)
    >>> +{
    >>> +#ifdef CONFIG_ACPI_PROCESSOR_AGGREGATOR
    >>> + power_saving_mwait_init();
    >>> + if (power_saving_mwait_eax == 0)
    >>> + return -EINVAL;
    >>> +
    >>> + return acpi_bus_register_driver(&acpi_pad_driver); +#else
    >>> + return 0;
    >>> +#endif
    >>> +}
    >>> +
    >>> +static inline void native_acpi_pad_exit(void)
    >>> +{
    >>> +#ifdef CONFIG_ACPI_PROCESSOR_AGGREGATOR
    >>> + acpi_bus_unregister_driver(&acpi_pad_driver);
    >>> +#endif
    >>> +}
    >>> +
    >>> +#ifdef CONFIG_PARAVIRT
    >>> +#include <asm/paravirt.h>
    >>> +#else
    >>> +static inline int __acpi_pad_init(void)
    >>> +{
    >>> + return native_acpi_pad_init();
    >>> +}
    >>> +
    >>> +static inline void __acpi_pad_exit(void)
    >>> +{
    >>> + native_acpi_pad_exit();
    >>> +}
    >>> +#endif
    >>> +
    >>> +#endif /* __ACPI_PAD_H__ */
    >>> --
    >>> 1.7.1
    >>
    >>
    >>
    >> _______________________________________________
    >> Xen-devel mailing list
    >> Xen-devel@lists.xensource.com
    >> http://lists.xensource.com/xen-devel



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