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Message-ID: <52C58138.1030301@citrix.com>
Date: Thu, 2 Jan 2014 15:09:44 +0000
From: David Vrabel <david.vrabel@...rix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: Fabio Fantoni <fabio.fantoni@....biz>, <axboe@...nel.dk>,
<leosilva@...ux.vnet.ibm.com>, <linux-fbdev@...r.kernel.org>,
<dmitry.torokhov@...il.com>, <ian.campbell@...rix.com>,
<stefano.stabellini@...citrix.com>, <linux-pci@...r.kernel.org>,
<netdev@...r.kernel.org>, <ashley@...leylai.com>,
<tpmdd@...horst.net>, <linux-kernel@...r.kernel.org>,
<mail@...jiv.net>, <tpmdd-devel@...ts.sourceforge.net>,
<tomi.valkeinen@...com>, <david.vrabel@...rix.com>,
<linux-input@...r.kernel.org>, <bhelgaas@...gle.com>,
<xen-devel@...ts.xenproject.org>, <boris.ostrovsky@...cle.com>,
<plagnioj@...osoft.com>, <peterhuewe@....de>
Subject: Re: [Xen-devel] [PATCH v3 1/2] xen/pvhvm: If xen_platform_pci=0 is
set don't blow up (v3).
On 31/12/13 14:32, Konrad Rzeszutek Wilk wrote:
>> That is because 'disks' is incorrect. It should have been 'ide-disks'
>>
>> [ 0.000000] unrecognised option 'disks' in parameter 'xen_emul_unplug'
>>
>> With the 'ide-disks' it should work. I will update the description to
>> mention 'ide-disks' instead of 'disks'. Thank you for finding this!
>>
>
> I've v4 with said update and will push it to Linus shortly.
>
> Thanks!
>
> P.S.
> Here is v4:
>
>>>From 275a81e7496d3532e5b4752703c50a7c8355a6c7 Mon Sep 17 00:00:00 2001
> From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Date: Tue, 26 Nov 2013 15:05:40 -0500
> Subject: [PATCH] xen/pvhvm: If xen_platform_pci=0 is set don't blow up (v4).
>
> The user has the option of disabling the platform driver:
> 00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)
>
> which is used to unplug the emulated drivers (IDE, Realtek 8169, etc)
> and allow the PV drivers to take over. If the user wishes
> to disable that they can set:
>
> xen_platform_pci=0
> (in the guest config file)
>
> or
> xen_emul_unplug=never
> (on the Linux command line)
>
> except it does not work properly. The PV drivers still try to
> load and since the Xen platform driver is not run - and it
> has not initialized the grant tables, most of the PV drivers
> stumble upon:
>
> input: Xen Virtual Keyboard as /devices/virtual/input/input5
> input: Xen Virtual Pointer as /devices/virtual/input/input6M
> ------------[ cut here ]------------
> kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206!
> invalid opcode: 0000 [#1] SMP
> Modules linked in: xen_kbdfront(+) xenfs xen_privcmd
> CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1
> Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013
> RIP: 0010:[<ffffffff813ddc40>] [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300
> Call Trace:
> [<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240
> [<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70
> [<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront]
> [<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront]
> [<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130
> [<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50
> [<ffffffff8145e9a9>] driver_probe_device+0x89/0x230
> [<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0
> [<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
> [<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
> [<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0
> [<ffffffff8145e7d9>] driver_attach+0x19/0x20
> [<ffffffff8145e260>] bus_add_driver+0x1a0/0x220
> [<ffffffff8145f1ff>] driver_register+0x5f/0xf0
> [<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20
> [<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40
> [<ffffffffa0015000>] ? 0xffffffffa0014fff
> [<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront]
> [<ffffffff81002049>] do_one_initcall+0x49/0x170
>
> .. snip..
>
> which is hardly nice. This patch fixes this by having each
> PV driver check for:
> - if running in PV, then it is fine to execute (as that is their
> native environment).
> - if running in HVM, check if user wanted 'xen_emul_unplug=never',
> in which case bail out and don't load any PV drivers.
> - if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
> does not exist, then bail out and not load PV drivers.
> - (v2) if running in HVM, and if the user wanted 'xen_emul_unplug=ide-disks',
> then bail out for all PV devices _except_ the block one.
> Ditto for the network one ('nics').
> - (v2) if running in HVM, and if the user wanted 'xen_emul_unplug=unnecessary'
> then load block PV driver, and also setup the legacy IDE paths.
> In (v3) make it actually load PV drivers.
[...]
> --- a/arch/x86/xen/platform-pci-unplug.c
> +++ b/arch/x86/xen/platform-pci-unplug.c
> @@ -69,6 +69,80 @@ static int check_platform_magic(void)
> return 0;
> }
>
> +bool xen_has_pv_devices()
> +{
> + if (!xen_domain())
> + return false;
> +
> + /* PV domains always have them. */
> + if (xen_pv_domain())
> + return true;
> +
> + /* And user has xen_platform_pci=0 set in guest config as
> + * driver did not modify the value. */
> + if (xen_platform_pci_unplug == 0)
> + return false;
> +
> + if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
> + return false;
> +
> + if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
> + return true;
> +
> + /* This is an odd one - we are going to run legacy
> + * and PV drivers at the same time. */
> + if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
> + return true;
> +
> + /* And the caller has to follow with xen_pv_{disk,nic}_devices
> + * to be certain which driver can load. */
> + return false;
This may result in:
xen_has_pv_devices() == false
xen_has_pv_disk_devices() == true
which looks odd to me. Surely xen_has_pv_*_devices() is a subset of
xen_has_pv_devices()?
David
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