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SubjectRe: [PATCH 11/11] Unplug emulated disks and nics
On 05/24/2010 11:27 AM, Stefano Stabellini wrote:
> Add a xen_emul_unplug command line option to the kernel to unplug
> xen emulated disks and nics.
>
> Set the default value of xen_emul_unplug depending on whether or
> not the Xen PV frontends and the Xen platform PCI driver have
> been compiled for this kernel (modules or built-in are both OK).
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> ---
> Documentation/kernel-parameters.txt | 11 +++
> arch/x86/xen/Makefile | 2 +-
> arch/x86/xen/enlighten.c | 1 +
> arch/x86/xen/platform-pci-unplug.c | 131 ++++++++++++++++++++++++++++++++++
> arch/x86/xen/xen-ops.h | 1 +
> drivers/xen/platform-pci.c | 4 +
> include/xen/interface/platform_pci.h | 46 ++++++++++++
> include/xen/platform_pci.h | 34 +++++++++
> 8 files changed, 229 insertions(+), 1 deletions(-)
> create mode 100644 arch/x86/xen/platform-pci-unplug.c
> create mode 100644 include/xen/interface/platform_pci.h
> create mode 100644 include/xen/platform_pci.h
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 839b21b..716eea8 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -113,6 +113,7 @@ parameter is applicable:
> More X86-64 boot options can be found in
> Documentation/x86/x86_64/boot-options.txt .
> X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
> + XEN Xen support is enabled
>
> In addition, the following text indicates that the option:
>
> @@ -2834,6 +2835,16 @@ and is between 256 and 4096 characters. It is defined in the file
> xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
> xd_geo= See header of drivers/block/xd.c.
>
> + xen_emul_unplug= [HW,X86,XEN]
> + Unplug Xen emulated devices
> + Format: [unplug0,][unplug1]
> + ide-disks -- unplug primary master IDE devices
> + aux-ide-disks -- unplug non-primary-master IDE devices
> + nics -- unplug network devices
> + all -- unplug all emulated devices (NICs and IDE disks)
> + ignore -- continue loading the Xen platform PCI driver even
> + if the version check failed
> +
> xirc2ps_cs= [NET,PCMCIA]
> Format:
> <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
> diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
> index 3bb4fc2..9309546 100644
> --- a/arch/x86/xen/Makefile
> +++ b/arch/x86/xen/Makefile
> @@ -12,7 +12,7 @@ CFLAGS_mmu.o := $(nostackp)
>
> obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \
> time.o xen-asm.o xen-asm_$(BITS).o \
> - grant-table.o suspend.o
> + grant-table.o suspend.o platform-pci-unplug.o
>
> obj-$(CONFIG_SMP) += smp.o
> obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index 88e8a09..fbf7c43 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -1354,6 +1354,7 @@ void __init xen_guest_init(void)
> if (xen_feature(XENFEAT_hvm_callback_vector))
> xen_have_vector_callback = 1;
> register_cpu_notifier(&xen_hvm_cpu_notifier);
> + xen_unplug_emulated_devices();
> have_vcpu_info_placement = 0;
> x86_init.irqs.intr_init = xen_init_IRQ;
> init_hvm_time();
> diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c
> new file mode 100644
> index 0000000..4094f29
> --- /dev/null
> +++ b/arch/x86/xen/platform-pci-unplug.c
> @@ -0,0 +1,131 @@
> +/******************************************************************************
> + * platform-pci-unplug.c
> + *
> + * Xen platform PCI device driver
> + * Copyright (c) 2010, Citrix
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
> + * Place - Suite 330, Boston, MA 02111-1307 USA.
> + *
> + */
> +
> +#include <asm/io.h>
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +
> +#include <xen/platform_pci.h>
> +#include <xen/interface/platform_pci.h>
> +
> +int xen_platform_pci;
> +EXPORT_SYMBOL_GPL(xen_platform_pci);
>

Could you give this a bit more of a descriptive name, type and/or
comment? What is it indicating about the xen_platform_pci driver? That
it has been detected? That it is in use? That it can be used? Is it
boolean, or can it have any value?

> +static int xen_emul_unplug;
> +
> +static int __init check_platform_magic(void)
> +{
> + short magic;
> + char protocol;
> +
> + magic = inw(XEN_IOPORT_MAGIC);
> + if (magic != XEN_IOPORT_MAGIC_VAL) {
> + printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n");
> + return -1;
> + }
> +
> + protocol = inb(XEN_IOPORT_PROTOVER);
> +
> + printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d\n",
> + protocol);
> +
> + switch (protocol) {
> + case 1:
> + outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
> + outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
> + if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
> + printk(KERN_ERR "Xen Platform: blacklisted by host\n");
> + return -3;
> + }
> + break;
> + default:
> + printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
> + return -2;
> + }
> +
> + return 0;
> +}
> +
> +void __init xen_unplug_emulated_devices(void)
> +{
> + int r;
> +
> + /* check the version of the xen platform PCI device */
> + r = check_platform_magic();
> + /* If the version matches enable the Xen platform PCI driver.
> + * Also enable the Xen platform PCI driver if the version is really old
> + * and the user told us to ignore it. */
> + if (!r || (r == -1 && (xen_emul_unplug & UNPLUG_IGNORE)))
> + xen_platform_pci = 1;
> + /* Set the default value of xen_emul_unplug depending on whether or
> + * not the Xen PV frontends and the Xen platform PCI driver have
> + * been compiled for this kernel (modules or built-in are both OK). */
> + if (xen_platform_pci && !xen_emul_unplug) {
> +#if (defined(CONFIG_XEN_NETDEV_FRONTEND) || \
> + defined(CONFIG_XEN_NETDEV_FRONTEND_MODULE)) && \
> + (defined(CONFIG_XEN_PLATFORM_PCI) || \
> + defined(CONFIG_XEN_PLATFORM_PCI_MODULE))
> + printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
> + "been compiled for this kernel: unplug emulated NICs.\n");
> + xen_emul_unplug |= UNPLUG_ALL_NICS;
> +#endif
> +#if (defined(CONFIG_XEN_BLKDEV_FRONTEND) || \
> + defined(CONFIG_XEN_BLKDEV_FRONTEND_MODULE)) && \
> + (defined(CONFIG_XEN_PLATFORM_PCI) || \
> + defined(CONFIG_XEN_PLATFORM_PCI_MODULE))
> + printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
> + "been compiled for this kernel: unplug emulated disks.\n"
> + "You might have to change the root device\n"
> + "from /dev/hd[a-d] to /dev/xvd[a-d]\n"
> + "in your root= kernel command line option\n");
> + xen_emul_unplug |= UNPLUG_ALL_IDE_DISKS;
> +#endif
> + }
> + /* Now unplug the emulated devices */
> + if (xen_platform_pci && !(xen_emul_unplug & UNPLUG_IGNORE))
> + outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
> +}
> +
> +static int __init parse_xen_emul_unplug(char *arg)
> +{
> + char *p, *q;
> +
> + for (p = arg; p; p = q) {
> + q = strchr(arg, ',');
> + if (q)
> + *q++ = '\0';
> + if (!strcmp(p, "all"))
> + xen_emul_unplug |= UNPLUG_ALL;
> + else if (!strcmp(p, "ide-disks"))
> + xen_emul_unplug |= UNPLUG_ALL_IDE_DISKS;
> + else if (!strcmp(p, "aux-ide-disks"))
> + xen_emul_unplug |= UNPLUG_AUX_IDE_DISKS;
> + else if (!strcmp(p, "nics"))
> + xen_emul_unplug |= UNPLUG_ALL_NICS;
> + else if (!strcmp(p, "ignore"))
> + xen_emul_unplug |= UNPLUG_IGNORE;
> + else
> + printk(KERN_WARNING "unrecognised option '%s' "
> + "in module parameter 'dev_unplug'\n", p);
> + }
> + return 0;
> +}
> +early_param("xen_emul_unplug", parse_xen_emul_unplug);
> diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
> index caf89ee..e146f5f 100644
> --- a/arch/x86/xen/xen-ops.h
> +++ b/arch/x86/xen/xen-ops.h
> @@ -40,6 +40,7 @@ void xen_vcpu_restore(void);
>
> void xen_callback_vector(void);
> void init_shared_info(void);
> +void __init xen_unplug_emulated_devices(void);
>
> void __init xen_build_dynamic_phys_to_machine(void);
>
> diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
> index 07c821c..de3ce1e 100644
> --- a/drivers/xen/platform-pci.c
> +++ b/drivers/xen/platform-pci.c
> @@ -27,6 +27,7 @@
> #include <linux/module.h>
> #include <linux/pci.h>
>
> +#include <xen/platform_pci.h>
> #include <xen/grant_table.h>
> #include <xen/xenbus.h>
> #include <xen/events.h>
> @@ -198,6 +199,9 @@ static int __init platform_pci_module_init(void)
> {
> int rc;
>
> + if (!xen_platform_pci)
> + return -ENODEV;
> +
> rc = pci_register_driver(&platform_driver);
> if (rc) {
> printk(KERN_INFO DRV_NAME
> diff --git a/include/xen/interface/platform_pci.h b/include/xen/interface/platform_pci.h
> new file mode 100644
> index 0000000..720eaf5
> --- /dev/null
> +++ b/include/xen/interface/platform_pci.h
> @@ -0,0 +1,46 @@
> +/******************************************************************************
> + * platform_pci.h
> + *
> + * Interface for granting foreign access to page frames, and receiving
> + * page-ownership transfers.
>

That doesn't look very accurate.

> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to
> + * deal in the Software without restriction, including without limitation the
> + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
> + * sell copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
>

Drop all this copyright goo; these kinds of definitions can't be
copyright in the US anyway.

> + */
> +
> +#ifndef __XEN_PUBLIC_PLATFORM_PCI_H__
> +#define __XEN_PUBLIC_PLATFORM_PCI_H__
> +
> +#define XEN_IOPORT_BASE 0x10
> +
> +#define XEN_IOPORT_PLATFLAGS (XEN_IOPORT_BASE + 0) /* 1 byte access (R/W) */
> +#define XEN_IOPORT_MAGIC (XEN_IOPORT_BASE + 0) /* 2 byte access (R) */
> +#define XEN_IOPORT_UNPLUG (XEN_IOPORT_BASE + 0) /* 2 byte access (W) */
> +#define XEN_IOPORT_DRVVER (XEN_IOPORT_BASE + 0) /* 4 byte access (W) */
> +
> +#define XEN_IOPORT_SYSLOG (XEN_IOPORT_BASE + 2) /* 1 byte access (W) */
> +#define XEN_IOPORT_PROTOVER (XEN_IOPORT_BASE + 2) /* 1 byte access (R) */
> +#define XEN_IOPORT_PRODNUM (XEN_IOPORT_BASE + 2) /* 2 byte access (W) */
> +
> +#define UNPLUG_ALL_IDE_DISKS 1
> +#define UNPLUG_ALL_NICS 2
> +#define UNPLUG_AUX_IDE_DISKS 4
> +#define UNPLUG_ALL 7
> +#define UNPLUG_IGNORE 8
>

These need XEN_ prefixes, otherwise they look too generic.

> +
> +#endif /* __XEN_PUBLIC_PLATFORM_PCI_H__ */
> diff --git a/include/xen/platform_pci.h b/include/xen/platform_pci.h
> new file mode 100644
> index 0000000..ae04d8a
> --- /dev/null
> +++ b/include/xen/platform_pci.h
> @@ -0,0 +1,34 @@
> +/******************************************************************************
> + * platform-pci.h
> + *
> + * Xen platform PCI device driver
> + * Copyright (c) 2004, Intel Corporation. <xiaofeng.ling@intel.com>
> + * Copyright (c) 2007, XenSource Inc.
> + * Copyright (c) 2010, Citrix
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
> + * Place - Suite 330, Boston, MA 02111-1307 USA.
>

Ditto; there's no copyrightable content in this file.

> + */
> +
> +#ifndef _XEN_PLATFORM_PCI_H
> +#define _XEN_PLATFORM_PCI_H
> +
> +#include <linux/version.h>
>
Why?

> +
> +#define XEN_IOPORT_MAGIC_VAL 0x49d2
> +#define XEN_IOPORT_LINUX_PRODNUM 0xffff
> +#define XEN_IOPORT_LINUX_DRVVER ((LINUX_VERSION_CODE << 8) + 0x0)
> +
> +extern int xen_platform_pci;
>

I still think these headers should be folded together. There's no point
in having them separate. They describe an ABI, so there's no need to
keep the files in sync with the master Xen sources (since the ABI will
never change).

J


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