lkml.org 
[lkml]   [2020]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC PATCH v3] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
From
Date
On 09/14/2020 05:46 PM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> On Mon, Sep 14, 2020 at 5:30 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>> On 09/14/2020 04:52 PM, Huacai Chen wrote:
>>> Hi, Tiezhu,
>>>
>>> How do you test kexec? kexec -e or systemctl kexec? Or both?
>> kexec -l vmlinux --append="root=/dev/sda2 console=ttyS0,115200"
>> kexec -e
> So you haven't tested "systemctl kexec"?

Yes, the distro I used is Loongnix which has not kexec service now.
Is there any problem when use systemctl kexec? If you have more details,
please let me know.

>
> Huacai
>>> P.S., Please also CC my gmail (chenhuacai@gmail.com) since lemote.com
>>> has some communication problems.
>> OK, no problem.
>>
>>> Huacai
>>>
>>>> 陈华才江苏航天龙梦信息技术有限公司/研发中心/软件部 ------------------ Original ------------------From: "Tiezhu Yang"<yangtiezhu@loongson.cn>;Date: Mon, Sep 14, 2020 03:57 PMTo: "Bjorn Helgaas"<bhelgaas@google.com>; Cc: "linux-pci"<linux-pci@vger.kernel.org>; "linux-kernel"<linux-kernel@vger.kernel.org>; "Rafael J. Wysocki"<rafael.j.wysocki@intel.com>; "Konstantin Khlebnikov"<khlebnikov@openvz.org>; "Khalid Aziz"<khalid.aziz@oracle.com>; "Vivek Goyal"<vgoyal@redhat.com>; "Lukas Wunner"<lukas@wunner.de>; "Oliver O'Halloran"<oohall@gmail.com>; "Huacai Chen"<chenhc@lemote.com>; "Jiaxun Yang"<jiaxun.yang@flygoat.com>; "Xuefeng Li"<lixuefeng@loongson.cn>; Subject: [RFC PATCH v3] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices After commit 745be2e700cd ("PCIe: portdrv: call pci_disable_device
>>>> during remove") and commit cc27b735ad3a ("PCI/portdrv: Turn off PCIe
>>>> services during shutdown"), it also calls pci_disable_device() during
>>>> shutdown, this leads to shutdown or reboot failure occasionally due to
>>>> clear PCI_COMMAND_MASTER on the device in do_pci_disable_device().
>>>>
>>>> drivers/pci/pci.c
>>>> static void do_pci_disable_device(struct pci_dev *dev)
>>>> {
>>>> u16 pci_command;
>>>>
>>>> pci_read_config_word(dev, PCI_COMMAND, &pci_command);
>>>> if (pci_command & PCI_COMMAND_MASTER) {
>>>> pci_command &= ~PCI_COMMAND_MASTER;
>>>> pci_write_config_word(dev, PCI_COMMAND, pci_command);
>>>> }
>>>>
>>>> pcibios_disable_device(dev);
>>>> }
>>>>
>>>> When remove "pci_command &= ~PCI_COMMAND_MASTER;", it can work well when
>>>> shutdown or reboot.
>>>>
>>>> As Oliver O'Halloran said, no need to call pci_disable_device() when
>>>> actually shutting down, but we should call pci_disable_device() before
>>>> handing over to the new kernel on kexec reboot, so we can do some
>>>> condition checks which are already executed afterwards by the function
>>>> pci_device_shutdown(), this is done by commit 4fc9bbf98fd6 ("PCI: Disable
>>>> Bus Master only on kexec reboot") and commit 6e0eda3c3898 ("PCI: Don't try
>>>> to disable Bus Master on disconnected PCI devices").
>>>>
>>>> drivers/pci/pci-driver.c
>>>> static void pci_device_shutdown(struct device *dev)
>>>> {
>>>> ...
>>>> if (drv && drv->shutdown)
>>>> drv->shutdown(pci_dev);
>>>>
>>>> /*
>>>> * If this is a kexec reboot, turn off Bus Master bit on the
>>>> * device to tell it to not continue to do DMA. Don't touch
>>>> * devices in D3cold or unknown states.
>>>> * If it is not a kexec reboot, firmware will hit the PCI
>>>> * devices with big hammer and stop their DMA any way.
>>>> */
>>>> if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
>>>> pci_clear_master(pci_dev);
>>>> }
>>>>
>>>> [ 36.159446] Call Trace:
>>>> [ 36.241688] [<ffffffff80211434>] show_stack+0x9c/0x130
>>>> [ 36.326619] [<ffffffff80661b70>] dump_stack+0xb0/0xf0
>>>> [ 36.410403] [<ffffffff806a8240>] pcie_portdrv_shutdown+0x18/0x78
>>>> [ 36.495302] [<ffffffff8069c6b4>] pci_device_shutdown+0x44/0x90
>>>> [ 36.580027] [<ffffffff807aac90>] device_shutdown+0x130/0x290
>>>> [ 36.664486] [<ffffffff80265448>] kernel_power_off+0x38/0x80
>>>> [ 36.748272] [<ffffffff80265634>] __do_sys_reboot+0x1a4/0x258
>>>> [ 36.831985] [<ffffffff80218b90>] syscall_common+0x34/0x58
>>>>
>>>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>>>> ---
>>>> drivers/pci/pcie/portdrv_core.c | 1 -
>>>> drivers/pci/pcie/portdrv_pci.c | 14 +++++++++++++-
>>>> 2 files changed, 13 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
>>>> index 50a9522..1991aca 100644
>>>> --- a/drivers/pci/pcie/portdrv_core.c
>>>> +++ b/drivers/pci/pcie/portdrv_core.c
>>>> @@ -491,7 +491,6 @@ void pcie_port_device_remove(struct pci_dev *dev)
>>>> {
>>>> device_for_each_child(&dev->dev, NULL, remove_iter);
>>>> pci_free_irq_vectors(dev);
>>>> - pci_disable_device(dev);
>>>> }
>>>>
>>>> /**
>>>> diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
>>>> index 3a3ce40..cab37a8 100644
>>>> --- a/drivers/pci/pcie/portdrv_pci.c
>>>> +++ b/drivers/pci/pcie/portdrv_pci.c
>>>> @@ -143,6 +143,18 @@ static void pcie_portdrv_remove(struct pci_dev *dev)
>>>> }
>>>>
>>>> pcie_port_device_remove(dev);
>>>> + pci_disable_device(dev);
>>>> +}
>>>> +
>>>> +static void pcie_portdrv_shutdown(struct pci_dev *dev)
>>>> +{
>>>> + if (pci_bridge_d3_possible(dev)) {
>>>> + pm_runtime_forbid(&dev->dev);
>>>> + pm_runtime_get_noresume(&dev->dev);
>>>> + pm_runtime_dont_use_autosuspend(&dev->dev);
>>>> + }
>>>> +
>>>> + pcie_port_device_remove(dev);
>>>> }
>>>>
>>>> static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
>>>> @@ -211,7 +223,7 @@ static struct pci_driver pcie_portdriver = {
>>>>
>>>> .probe = pcie_portdrv_probe,
>>>> .remove = pcie_portdrv_remove,
>>>> - .shutdown = pcie_portdrv_remove,
>>>> + .shutdown = pcie_portdrv_shutdown,
>>>>
>>>> .err_handler = &pcie_portdrv_err_handler,
>>>>
>>>> --
>>>> 2.1.0

\
 
 \ /
  Last update: 2020-09-14 19:53    [W:0.073 / U:4.224 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site