* [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
@ 2020-09-13 20:29 Tiezhu Yang
2020-09-14 4:06 ` Lukas Wunner
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Tiezhu Yang @ 2020-09-13 20:29 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: Konstantin Khlebnikov, Khalid Aziz, Vivek Goyal, Lukas Wunner,
oohall, rafael.j.wysocki, Xuefeng Li, Huacai Chen, Jiaxun Yang,
linux-pci, linux-kernel
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.
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 similar with 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 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);
}
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
drivers/pci/pcie/portdrv_core.c | 1 -
drivers/pci/pcie/portdrv_pci.c | 25 ++++++++++++++++++++++++-
2 files changed, 24 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..ce89a9e8 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/aer.h>
#include <linux/dmi.h>
+#include <linux/kexec.h>
#include "../pci.h"
#include "portdrv.h"
@@ -143,6 +144,28 @@ 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);
+
+ /*
+ * 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 && (dev->current_state <= PCI_D3hot))
+ pci_disable_device(dev);
}
static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
@@ -211,7 +234,7 @@ static void pcie_portdrv_err_resume(struct pci_dev *dev)
.probe = pcie_portdrv_probe,
.remove = pcie_portdrv_remove,
- .shutdown = pcie_portdrv_remove,
+ .shutdown = pcie_portdrv_shutdown,
.err_handler = &pcie_portdrv_err_handler,
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
2020-09-13 20:29 [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices Tiezhu Yang
@ 2020-09-14 4:06 ` Lukas Wunner
2020-09-14 6:13 ` Tiezhu Yang
[not found] ` <tencent_44F0201A70619BA613F16BA4@qq.com>
2020-09-14 5:59 ` kernel test robot
2 siblings, 1 reply; 7+ messages in thread
From: Lukas Wunner @ 2020-09-14 4:06 UTC (permalink / raw)
To: Tiezhu Yang
Cc: Bjorn Helgaas, Konstantin Khlebnikov, Khalid Aziz, Vivek Goyal,
oohall, rafael.j.wysocki, Xuefeng Li, Huacai Chen, Jiaxun Yang,
linux-pci, linux-kernel
On Mon, Sep 14, 2020 at 04:29:10AM +0800, Tiezhu Yang wrote:
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -143,6 +144,28 @@ 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);
> +
> + /*
> + * 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 && (dev->current_state <= PCI_D3hot))
> + pci_disable_device(dev);
The last portion of this function is already executed afterwards by
pci_device_shutdown(). You don't need to duplicate it here:
device_shutdown()
dev->bus->shutdown() == pci_device_shutdown()
drv->shutdown() == pcie_portdrv_shutdown()
pci_disable_device()
pci_disable_device()
Thanks,
Lukas
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
[not found] ` <tencent_44F0201A70619BA613F16BA4@qq.com>
@ 2020-09-14 4:31 ` Huacai Chen
2020-09-14 6:17 ` Tiezhu Yang
0 siblings, 1 reply; 7+ messages in thread
From: Huacai Chen @ 2020-09-14 4:31 UTC (permalink / raw)
To: Tiezhu Yang, Bjorn Helgaas
Cc: Konstantin Khlebnikov, Khalid Aziz, Vivek Goyal, Lukas Wunner,
oohall, rafael.j.wysocki, Xuefeng Li, Jiaxun Yang, linux-pci,
linux-kernel, zhouyanjie, git
Hi, Tiezhu
> ------------------ Original ------------------
> From: "Tiezhu Yang"<yangtiezhu@loongson.cn>;
> Date: Mon, Sep 14, 2020 04:29 AM
> To: "Bjorn Helgaas"<bhelgaas@google.com>;
> Cc: "Konstantin Khlebnikov"<khlebnikov@openvz.org>; "Khalid Aziz"<khalid.aziz@oracle.com>; "Vivek Goyal"<vgoyal@redhat.com>; "Lukas Wunner"<lukas@wunner.de>; "oohall"<oohall@gmail.com>; "rafael.j.wysocki"<rafael.j.wysocki@intel.com>; "Xuefeng Li"<lixuefeng@loongson.cn>; "Huacai Chen"<chenhc@lemote.com>; "Jiaxun Yang"<jiaxun.yang@flygoat.com>; "linux-pci"<linux-pci@vger.kernel.org>; "linux-kernel"<linux-kernel@vger.kernel.org>;
> Subject: [RFC PATCH v2] 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.
>
> 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 similar with 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 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);
> }
Have you really tried kexec? Why do you think kexec can disable pci
device successfully while normal reboot/poweroff cannot?
Huacai
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
> drivers/pci/pcie/portdrv_core.c | 1 -
> drivers/pci/pcie/portdrv_pci.c | 25 ++++++++++++++++++++++++-
> 2 files changed, 24 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..ce89a9e8 100644
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -15,6 +15,7 @@
> #include <linux/init.h>
> #include <linux/aer.h>
> #include <linux/dmi.h>
> +#include <linux/kexec.h>
>
> #include "../pci.h"
> #include "portdrv.h"
> @@ -143,6 +144,28 @@ 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);
> +
> + /*
> + * 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 && (dev->current_state <= PCI_D3hot))
> + pci_disable_device(dev);
> }
>
> static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
> @@ -211,7 +234,7 @@ static void pcie_portdrv_err_resume(struct pci_dev *dev)
>
> .probe = pcie_portdrv_probe,
> .remove = pcie_portdrv_remove,
> - .shutdown = pcie_portdrv_remove,
> + .shutdown = pcie_portdrv_shutdown,
>
> .err_handler = &pcie_portdrv_err_handler,
>
> --
> 1.8.3.1
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
2020-09-13 20:29 [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices Tiezhu Yang
2020-09-14 4:06 ` Lukas Wunner
[not found] ` <tencent_44F0201A70619BA613F16BA4@qq.com>
@ 2020-09-14 5:59 ` kernel test robot
2 siblings, 0 replies; 7+ messages in thread
From: kernel test robot @ 2020-09-14 5:59 UTC (permalink / raw)
To: kbuild-all
[-- Attachment #1: Type: text/plain, Size: 2598 bytes --]
Hi Tiezhu,
[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on pci/next]
[also build test WARNING on v5.9-rc5 next-20200911]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Tiezhu-Yang/PCI-portdrv-Only-disable-Bus-Master-on-kexec-reboot-and-connected-PCI-devices/20200914-043100
base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: x86_64-randconfig-s021-20200913 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.2-191-g10164920-dirty
# save the attached .config to linux build tree
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
sparse warnings: (new ones prefixed by >>)
>> drivers/pci/pcie/portdrv_pci.c:167:38: sparse: sparse: restricted pci_power_t degrades to integer
drivers/pci/pcie/portdrv_pci.c:167:57: sparse: sparse: restricted pci_power_t degrades to integer
# https://github.com/0day-ci/linux/commit/554a10648754bd244b64a233c257821c4719be0e
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Tiezhu-Yang/PCI-portdrv-Only-disable-Bus-Master-on-kexec-reboot-and-connected-PCI-devices/20200914-043100
git checkout 554a10648754bd244b64a233c257821c4719be0e
vim +167 drivers/pci/pcie/portdrv_pci.c
149
150 static void pcie_portdrv_shutdown(struct pci_dev *dev)
151 {
152 if (pci_bridge_d3_possible(dev)) {
153 pm_runtime_forbid(&dev->dev);
154 pm_runtime_get_noresume(&dev->dev);
155 pm_runtime_dont_use_autosuspend(&dev->dev);
156 }
157
158 pcie_port_device_remove(dev);
159
160 /*
161 * If this is a kexec reboot, turn off Bus Master bit on the
162 * device to tell it to not continue to do DMA. Don't touch
163 * devices in D3cold or unknown states.
164 * If it is not a kexec reboot, firmware will hit the PCI
165 * devices with big hammer and stop their DMA any way.
166 */
> 167 if (kexec_in_progress && (dev->current_state <= PCI_D3hot))
168 pci_disable_device(dev);
169 }
170
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 32722 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
2020-09-14 4:06 ` Lukas Wunner
@ 2020-09-14 6:13 ` Tiezhu Yang
2020-09-14 6:30 ` Tiezhu Yang
0 siblings, 1 reply; 7+ messages in thread
From: Tiezhu Yang @ 2020-09-14 6:13 UTC (permalink / raw)
To: Lukas Wunner
Cc: Bjorn Helgaas, Konstantin Khlebnikov, Khalid Aziz, Vivek Goyal,
oohall, rafael.j.wysocki, Xuefeng Li, Huacai Chen, Jiaxun Yang,
linux-pci, linux-kernel
On 09/14/2020 12:06 PM, Lukas Wunner wrote:
> On Mon, Sep 14, 2020 at 04:29:10AM +0800, Tiezhu Yang wrote:
>> --- a/drivers/pci/pcie/portdrv_pci.c
>> +++ b/drivers/pci/pcie/portdrv_pci.c
>> @@ -143,6 +144,28 @@ 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);
>> +
>> + /*
>> + * 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 && (dev->current_state <= PCI_D3hot))
>> + pci_disable_device(dev);
> The last portion of this function is already executed afterwards by
> pci_device_shutdown(). You don't need to duplicate it here:
>
> device_shutdown()
> dev->bus->shutdown() == pci_device_shutdown()
> drv->shutdown() == pcie_portdrv_shutdown()
> pci_disable_device()
> pci_disable_device()
pcie_port_device_remove() deletes pci_disable_device(dev) at the beginning of this patch.
diff
<https://lore.kernel.org/linux-pci/CAAhV-H5-X9OcBe3iRxF8PnKW-0j_10FVqm8cbiqW2-Lv4mTTdQ@mail.gmail.com/T/#iZ2e.:..:1600028950-10644-1-git-send-email-yangtiezhu::40loongson.cn:0drivers:pci:pcie:portdrv_core.c>
--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); }
>
> Thanks,
>
> Lukas
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
2020-09-14 4:31 ` Huacai Chen
@ 2020-09-14 6:17 ` Tiezhu Yang
0 siblings, 0 replies; 7+ messages in thread
From: Tiezhu Yang @ 2020-09-14 6:17 UTC (permalink / raw)
To: Huacai Chen, Bjorn Helgaas
Cc: Konstantin Khlebnikov, Khalid Aziz, Vivek Goyal, Lukas Wunner,
oohall, rafael.j.wysocki, Xuefeng Li, Jiaxun Yang, linux-pci,
linux-kernel, zhouyanjie, git
On 09/14/2020 12:31 PM, Huacai Chen wrote:
> Hi, Tiezhu
>
>> ------------------ Original ------------------
>> From: "Tiezhu Yang"<yangtiezhu@loongson.cn>;
>> Date: Mon, Sep 14, 2020 04:29 AM
>> To: "Bjorn Helgaas"<bhelgaas@google.com>;
>> Cc: "Konstantin Khlebnikov"<khlebnikov@openvz.org>; "Khalid Aziz"<khalid.aziz@oracle.com>; "Vivek Goyal"<vgoyal@redhat.com>; "Lukas Wunner"<lukas@wunner.de>; "oohall"<oohall@gmail.com>; "rafael.j.wysocki"<rafael.j.wysocki@intel.com>; "Xuefeng Li"<lixuefeng@loongson.cn>; "Huacai Chen"<chenhc@lemote.com>; "Jiaxun Yang"<jiaxun.yang@flygoat.com>; "linux-pci"<linux-pci@vger.kernel.org>; "linux-kernel"<linux-kernel@vger.kernel.org>;
>> Subject: [RFC PATCH v2] 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.
>>
>> 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 similar with 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 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);
>> }
> Have you really tried kexec? Why do you think kexec can disable pci
> device successfully while normal reboot/poweroff cannot?
Yes, I test it on kexec reboot, it works well.
>
> Huacai
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>> ---
>> drivers/pci/pcie/portdrv_core.c | 1 -
>> drivers/pci/pcie/portdrv_pci.c | 25 ++++++++++++++++++++++++-
>> 2 files changed, 24 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..ce89a9e8 100644
>> --- a/drivers/pci/pcie/portdrv_pci.c
>> +++ b/drivers/pci/pcie/portdrv_pci.c
>> @@ -15,6 +15,7 @@
>> #include <linux/init.h>
>> #include <linux/aer.h>
>> #include <linux/dmi.h>
>> +#include <linux/kexec.h>
>>
>> #include "../pci.h"
>> #include "portdrv.h"
>> @@ -143,6 +144,28 @@ 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);
>> +
>> + /*
>> + * 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 && (dev->current_state <= PCI_D3hot))
>> + pci_disable_device(dev);
>> }
>>
>> static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
>> @@ -211,7 +234,7 @@ static void pcie_portdrv_err_resume(struct pci_dev *dev)
>>
>> .probe = pcie_portdrv_probe,
>> .remove = pcie_portdrv_remove,
>> - .shutdown = pcie_portdrv_remove,
>> + .shutdown = pcie_portdrv_shutdown,
>>
>> .err_handler = &pcie_portdrv_err_handler,
>>
>> --
>> 1.8.3.1
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices
2020-09-14 6:13 ` Tiezhu Yang
@ 2020-09-14 6:30 ` Tiezhu Yang
0 siblings, 0 replies; 7+ messages in thread
From: Tiezhu Yang @ 2020-09-14 6:30 UTC (permalink / raw)
To: Lukas Wunner
Cc: Bjorn Helgaas, Konstantin Khlebnikov, Khalid Aziz, Vivek Goyal,
oohall, rafael.j.wysocki, Xuefeng Li, Huacai Chen, Jiaxun Yang,
linux-pci, linux-kernel
On 09/14/2020 02:13 PM, Tiezhu Yang wrote:
> On 09/14/2020 12:06 PM, Lukas Wunner wrote:
>> On Mon, Sep 14, 2020 at 04:29:10AM +0800, Tiezhu Yang wrote:
>>> --- a/drivers/pci/pcie/portdrv_pci.c
>>> +++ b/drivers/pci/pcie/portdrv_pci.c
>>> @@ -143,6 +144,28 @@ 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);
>>> +
>>> + /*
>>> + * 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 && (dev->current_state <= PCI_D3hot))
>>> + pci_disable_device(dev);
>> The last portion of this function is already executed afterwards by
>> pci_device_shutdown(). You don't need to duplicate it here:
>>
>> device_shutdown()
>> dev->bus->shutdown() == pci_device_shutdown()
>> drv->shutdown() == pcie_portdrv_shutdown()
>> pci_disable_device()
>> pci_disable_device()
>
> pcie_port_device_remove() deletes pci_disable_device(dev) at the
> beginning of this patch.
Sorry, I misunderstood your meaning, you are right.
>
>
> diff
> <https://lore.kernel.org/linux-pci/CAAhV-H5-X9OcBe3iRxF8PnKW-0j_10FVqm8cbiqW2-Lv4mTTdQ@mail.gmail.com/T/#iZ2e.:..:1600028950-10644-1-git-send-email-yangtiezhu::40loongson.cn:0drivers:pci:pcie:portdrv_core.c>
> --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); }
>
>>
>> Thanks,
>>
>> Lukas
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-09-14 6:30 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-13 20:29 [RFC PATCH v2] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices Tiezhu Yang
2020-09-14 4:06 ` Lukas Wunner
2020-09-14 6:13 ` Tiezhu Yang
2020-09-14 6:30 ` Tiezhu Yang
[not found] ` <tencent_44F0201A70619BA613F16BA4@qq.com>
2020-09-14 4:31 ` Huacai Chen
2020-09-14 6:17 ` Tiezhu Yang
2020-09-14 5:59 ` kernel test robot
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