[RESEND,v3] PCI/AER: Save and restore AER config state
diff mbox series

Message ID 92EBB4272BF81E4089A7126EC1E7B28479AE1486@IRSMSX101.ger.corp.intel.com
State Superseded
Delegated to: Bjorn Helgaas
Headers show
Series
  • [RESEND,v3] PCI/AER: Save and restore AER config state
Related show

Commit Message

Patel, Mayurkumar Oct. 8, 2019, 5:22 p.m. UTC
This patch provides AER config save and restore capabilities. After system
resume AER config registers settings are lost. Not restoring AER root error
command register bits on root port if they were set, disables generation
of an AER interrupt reported by function as described in PCIe spec r4.0,
sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
also required to maintain same state prior to system suspend to maintain
AER interrupts behavior.

Signed-off-by: Mayurkumar Patel <mayurkumar.patel@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/pci/access.c   |  2 +-
drivers/pci/pci.c      |  2 ++
drivers/pci/pci.h      |  1 +
drivers/pci/pcie/aer.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/aer.h    |  4 ++++
5 files changed, 67 insertions(+), 1 deletion(-)

Comments

Bjorn Helgaas Oct. 17, 2019, 11:09 p.m. UTC | #1
On Tue, Oct 08, 2019 at 05:22:34PM +0000, Patel, Mayurkumar wrote:
> This patch provides AER config save and restore capabilities. After system
> resume AER config registers settings are lost. Not restoring AER root error
> command register bits on root port if they were set, disables generation
> of an AER interrupt reported by function as described in PCIe spec r4.0,
> sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
> also required to maintain same state prior to system suspend to maintain
> AER interrupts behavior.
> 
> Signed-off-by: Mayurkumar Patel <mayurkumar.patel@intel.com>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/pci/access.c   |  2 +-
> drivers/pci/pci.c      |  2 ++
> drivers/pci/pci.h      |  1 +
> drivers/pci/pcie/aer.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/aer.h    |  4 ++++
> 5 files changed, 67 insertions(+), 1 deletion(-)

Can you send this as plain text?  The patch seems to be a
quoted-printable attachment, and I can't figure out how to decode it
in a way "patch" will understand.

> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> index 544922f..962295c 100644
> --- a/drivers/pci/access.c
> +++ b/drivers/pci/access.c
> @@ -364,7 +364,7 @@ static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
> 	       pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT;
> }
> 
> -static inline bool pcie_cap_has_rtctl(const struct pci_dev *dev)
> +bool pcie_cap_has_rtctl(const struct pci_dev *dev)
> {
> 	int type = pci_pcie_type(dev);
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 8abc843..40d5507 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1340,6 +1340,7 @@ int pci_save_state(struct pci_dev *dev)
> 
>  	pci_save_ltr_state(dev);
> 	pci_save_dpc_state(dev);
> +	pci_save_aer_state(dev);
> 	return pci_save_vc_state(dev);
> }
> EXPORT_SYMBOL(pci_save_state);
> @@ -1453,6 +1454,7 @@ void pci_restore_state(struct pci_dev *dev)
> 	pci_restore_dpc_state(dev);
> 
>  	pci_cleanup_aer_error_status_regs(dev);
> +	pci_restore_aer_state(dev);
> 
>  	pci_restore_config_space(dev);
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 9cb9938..268995b 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -12,6 +12,7 @@ extern const unsigned char pcie_link_speed[];
> extern bool pci_early_dump;
> 
>  bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
> +bool pcie_cap_has_rtctl(const struct pci_dev *dev);
> 
>  /* Functions internal to the PCI core code */
> 
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index b45bc47..7c41dec 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -448,6 +448,53 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
> 	return 0;
> }
> 
> +
> +void pci_save_aer_state(struct pci_dev *dev)
> +{
> +	struct pci_cap_saved_state *save_state;
> +	u32 *cap;
> +	int pos;
> +
> +	pos = dev->aer_cap;
> +	if (!pos)
> +		return;
> +
> +	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
> +	if (!save_state)
> +		return;
> +
> +	cap = &save_state->cap.data[0];
> +	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, cap++);
> +	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, cap++);
> +	pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, cap++);
> +	pci_read_config_dword(dev, pos + PCI_ERR_CAP, cap++);
> +	if (pcie_cap_has_rtctl(dev))
> +		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, cap++);
> +}
> +
> +void pci_restore_aer_state(struct pci_dev *dev)
> +{
> +	struct pci_cap_saved_state *save_state;
> +	u32 *cap;
> +	int pos;
> +
> +	pos = dev->aer_cap;
> +	if (!pos)
> +		return;
> +
> +	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
> +	if (!save_state)
> +		return;
> +
> +	cap = &save_state->cap.data[0];
> +	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, *cap++);
> +	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, *cap++);
> +	pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, *cap++);
> +	pci_write_config_dword(dev, pos + PCI_ERR_CAP, *cap++);
> +	if (pcie_cap_has_rtctl(dev))
> +		pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, *cap++);
> +}
> +
> void pci_aer_init(struct pci_dev *dev)
> {
> 	dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> @@ -455,6 +502,18 @@ void pci_aer_init(struct pci_dev *dev)
> 	if (dev->aer_cap)
> 		dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);
> 
> +	/*
> +	 * Since PCI_ERR_ROOT_COMMAND is only valid for root port and root
> +	 * complex event collector, as per PCIe 4.0 section 7.8.4, interpret
> +	 * the device/port type to determine the availability of additional
> +	 * root port and root complex event collector register.
> +	 */
> +	if (pcie_cap_has_rtctl(dev))
> +		pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR,
> +					sizeof(u32) * 5);
> +	else
> +		pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR,
> +					sizeof(u32) * 4);
> 	pci_cleanup_aer_error_status_regs(dev);
> }
> 
> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index 514bffa..fa19e01 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -46,6 +46,8 @@ int pci_enable_pcie_error_reporting(struct pci_dev *dev);
> int pci_disable_pcie_error_reporting(struct pci_dev *dev);
> int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
> int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
> +void pci_save_aer_state(struct pci_dev *dev);
> +void pci_restore_aer_state(struct pci_dev *dev);
> #else
> static inline int pci_enable_pcie_error_reporting(struct pci_dev *dev)
> {
> @@ -63,6 +65,8 @@ static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
> {
> 	return -EINVAL;
> }
> +static inline void pci_save_aer_state(struct pci_dev *dev) {}
> +static inline void pci_restore_aer_state(struct pci_dev *dev) {}
> #endif
> 
>  void cper_print_aer(struct pci_dev *dev, int aer_severity,
> -- 
> 2.7.4
> 
> Mayurkumar Patel
> Intel Deutschland GmbH
> Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
> Registered Office: Munich
> Commercial Register: Amtsgericht Muenchen HRB 186928
> 
> 
> 
> Intel Deutschland GmbH
> Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
> Tel: +49 89 99 8853-0, www.intel.de
> Managing Directors: Christin Eisenschmid, Gary Kershaw
> Chairperson of the Supervisory Board: Nicole Lau
> Registered Office: Munich
> Commercial Register: Amtsgericht Muenchen HRB 186928
>
Andy Shevchenko Oct. 18, 2019, 8:47 a.m. UTC | #2
On Thu, Oct 17, 2019 at 06:09:08PM -0500, Bjorn Helgaas wrote:
> On Tue, Oct 08, 2019 at 05:22:34PM +0000, Patel, Mayurkumar wrote:
> > This patch provides AER config save and restore capabilities. After system
> > resume AER config registers settings are lost. Not restoring AER root error
> > command register bits on root port if they were set, disables generation
> > of an AER interrupt reported by function as described in PCIe spec r4.0,
> > sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
> > also required to maintain same state prior to system suspend to maintain
> > AER interrupts behavior.

> Can you send this as plain text?  The patch seems to be a
> quoted-printable attachment, and I can't figure out how to decode it
> in a way "patch" will understand.

I understand that it changes your workflow and probably you won't like,
though you can use patchwork (either thru web, or directly thru client(s)
like git pw): https://patchwork.ozlabs.org/patch/1173439/
Bjorn Helgaas Oct. 18, 2019, 12:37 p.m. UTC | #3
On Fri, Oct 18, 2019 at 11:47:21AM +0300, andriy.shevchenko@linux.intel.com wrote:
> On Thu, Oct 17, 2019 at 06:09:08PM -0500, Bjorn Helgaas wrote:
> > On Tue, Oct 08, 2019 at 05:22:34PM +0000, Patel, Mayurkumar wrote:
> > > This patch provides AER config save and restore capabilities. After system
> > > resume AER config registers settings are lost. Not restoring AER root error
> > > command register bits on root port if they were set, disables generation
> > > of an AER interrupt reported by function as described in PCIe spec r4.0,
> > > sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
> > > also required to maintain same state prior to system suspend to maintain
> > > AER interrupts behavior.
> 
> > Can you send this as plain text?  The patch seems to be a
> > quoted-printable attachment, and I can't figure out how to decode it
> > in a way "patch" will understand.
> 
> I understand that it changes your workflow and probably you won't like,
> though you can use patchwork (either thru web, or directly thru client(s)
> like git pw): https://patchwork.ozlabs.org/patch/1173439/

I had already tried that and "patch" still thought it was corrupted.
Same thing happens when downloading from lore.kernel.org.  Did you try
it and it worked for you?

07:30:22 ~/linux (master)$ git checkout -b test master
Switched to a new branch 'test'
07:30:31 ~/linux (test)$ wget -O patch https://patchwork.ozlabs.org/patch/1173439/mbox/
--2019-10-18 07:30:47--  https://patchwork.ozlabs.org/patch/1173439/mbox/
Resolving patchwork.ozlabs.org (patchwork.ozlabs.org)... 203.11.71.1, 2401:3900:2:1::2
Connecting to patchwork.ozlabs.org (patchwork.ozlabs.org)|203.11.71.1|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 8919 (8.7K) [text/plain]
Saving to: ‘patch’

patch               100%[===================>]   8.71K  --.-KB/s    in 0.001s

2019-10-18 07:30:48 (9.41 MB/s) - ‘patch’ saved [8919/8919]

07:30:48 ~/linux (test)$ git am patch
Applying: PCI/AER: Save and restore AER config state
error: corrupt patch at line 14
Patch failed at 0001 PCI/AER: Save and restore AER config state
hint: Use 'git am --show-current-patch' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

07:36:11 ~/linux (test)$ wget -O patch.lore https://lore.kernel.org/linux-pci/92EBB4272BF81E4089A7126EC1E7B28479AE1486@IRSMSX101.ger.corp.intel.com/raw
--2019-10-18 07:36:16--  https://lore.kernel.org/linux-pci/92EBB4272BF81E4089A7126EC1E7B28479AE1486@IRSMSX101.ger.corp.intel.com/raw
Resolving lore.kernel.org (lore.kernel.org)... 54.203.26.224, 52.38.63.62
Connecting to lore.kernel.org (lore.kernel.org)|54.203.26.224|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 9744 (9.5K) [text/plain]
Saving to: ‘patch.lore’

patch.lore          100%[===================>]   9.52K  --.-KB/s    in 0s

2019-10-18 07:36:16 (46.7 MB/s) - ‘patch.lore’ saved [9744/9744]

07:36:16 ~/linux (test)$ git am patch.lore
Applying: PCI/AER: Save and restore AER config state
error: corrupt patch at line 14
Patch failed at 0001 PCI/AER: Save and restore AER config state
hint: Use 'git am --show-current-patch' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Andy Shevchenko Oct. 18, 2019, 1:40 p.m. UTC | #4
On Fri, Oct 18, 2019 at 07:37:29AM -0500, Bjorn Helgaas wrote:
> On Fri, Oct 18, 2019 at 11:47:21AM +0300, andriy.shevchenko@linux.intel.com wrote:
> > On Thu, Oct 17, 2019 at 06:09:08PM -0500, Bjorn Helgaas wrote:
> > > On Tue, Oct 08, 2019 at 05:22:34PM +0000, Patel, Mayurkumar wrote:
> > > > This patch provides AER config save and restore capabilities. After system
> > > > resume AER config registers settings are lost. Not restoring AER root error
> > > > command register bits on root port if they were set, disables generation
> > > > of an AER interrupt reported by function as described in PCIe spec r4.0,
> > > > sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
> > > > also required to maintain same state prior to system suspend to maintain
> > > > AER interrupts behavior.
> > 
> > > Can you send this as plain text?  The patch seems to be a
> > > quoted-printable attachment, and I can't figure out how to decode it
> > > in a way "patch" will understand.
> > 
> > I understand that it changes your workflow and probably you won't like,
> > though you can use patchwork (either thru web, or directly thru client(s)
> > like git pw): https://patchwork.ozlabs.org/patch/1173439/
> 
> I had already tried that and "patch" still thought it was corrupted.
> Same thing happens when downloading from lore.kernel.org.  Did you try
> it and it worked for you?

Hmm... indeed. patch work recognizes the patch, but fails to validate it...

Original mbox is broken :(
https://marc.info/?l=linux-pci&m=157055537210812&w=2&q=mbox

So, here is for sure the problem on the sender's side.
Sorry for the noise from me.
Patel, Mayurkumar Oct. 18, 2019, 3:01 p.m. UTC | #5
> 
> On Fri, Oct 18, 2019 at 07:37:29AM -0500, Bjorn Helgaas wrote:
> > On Fri, Oct 18, 2019 at 11:47:21AM +0300, andriy.shevchenko@linux.intel.com wrote:
> > > On Thu, Oct 17, 2019 at 06:09:08PM -0500, Bjorn Helgaas wrote:
> > > > On Tue, Oct 08, 2019 at 05:22:34PM +0000, Patel, Mayurkumar wrote:
> > > > > This patch provides AER config save and restore capabilities. After system
> > > > > resume AER config registers settings are lost. Not restoring AER root error
> > > > > command register bits on root port if they were set, disables generation
> > > > > of an AER interrupt reported by function as described in PCIe spec r4.0,
> > > > > sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
> > > > > also required to maintain same state prior to system suspend to maintain
> > > > > AER interrupts behavior.
> > >
> > > > Can you send this as plain text?  The patch seems to be a
> > > > quoted-printable attachment, and I can't figure out how to decode it
> > > > in a way "patch" will understand.
> > >
> > > I understand that it changes your workflow and probably you won't like,
> > > though you can use patchwork (either thru web, or directly thru client(s)
> > > like git pw): https://patchwork.ozlabs.org/patch/1173439/
> >
> > I had already tried that and "patch" still thought it was corrupted.
> > Same thing happens when downloading from lore.kernel.org.  Did you try
> > it and it worked for you?
> 
> Hmm... indeed. patch work recognizes the patch, but fails to validate it...
> 
> Original mbox is broken :(
> https://marc.info/?l=linux-pci&m=157055537210812&w=2&q=mbox
> 
> So, here is for sure the problem on the sender's side.
> Sorry for the noise from me.
> 

Sorry my mistake. My mail client seems to have re-formatted this patch and removed spaces from
the front of untouch lines. I ll fix my mail client settigns and resend it in plain text again.

> --
> With Best Regards,
> Andy Shevchenko
> 

Intel Deutschland GmbH
Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de
Managing Directors: Christin Eisenschmid, Gary Kershaw
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
Bjorn Helgaas Oct. 18, 2019, 4:21 p.m. UTC | #6
On Fri, Oct 18, 2019 at 03:01:00PM +0000, Patel, Mayurkumar wrote:
> > On Fri, Oct 18, 2019 at 07:37:29AM -0500, Bjorn Helgaas wrote:
> > > On Fri, Oct 18, 2019 at 11:47:21AM +0300, andriy.shevchenko@linux.intel.com wrote:
> > > > On Thu, Oct 17, 2019 at 06:09:08PM -0500, Bjorn Helgaas wrote:
> > > > > On Tue, Oct 08, 2019 at 05:22:34PM +0000, Patel, Mayurkumar wrote:
> > > > > > This patch provides AER config save and restore capabilities. After system
> > > > > > resume AER config registers settings are lost. Not restoring AER root error
> > > > > > command register bits on root port if they were set, disables generation
> > > > > > of an AER interrupt reported by function as described in PCIe spec r4.0,
> > > > > > sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
> > > > > > also required to maintain same state prior to system suspend to maintain
> > > > > > AER interrupts behavior.
> > > >
> > > > > Can you send this as plain text?  The patch seems to be a
> > > > > quoted-printable attachment, and I can't figure out how to decode it
> > > > > in a way "patch" will understand.
> > > >
> > > > I understand that it changes your workflow and probably you won't like,
> > > > though you can use patchwork (either thru web, or directly thru client(s)
> > > > like git pw): https://patchwork.ozlabs.org/patch/1173439/
> > >
> > > I had already tried that and "patch" still thought it was corrupted.
> > > Same thing happens when downloading from lore.kernel.org.  Did you try
> > > it and it worked for you?
> > 
> > Hmm... indeed. patch work recognizes the patch, but fails to validate it...
> > 
> > Original mbox is broken :(
> > https://marc.info/?l=linux-pci&m=157055537210812&w=2&q=mbox
> > 
> > So, here is for sure the problem on the sender's side.
> > Sorry for the noise from me.
> > 
> 
> Sorry my mistake. My mail client seems to have re-formatted this
> patch and removed spaces from the front of untouch lines. I ll fix
> my mail client settigns and resend it in plain text again.

You can always test it by sending the email to yourself to make sure
"git am" can apply it.

Bjorn

Patch
diff mbox series

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 544922f..962295c 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -364,7 +364,7 @@  static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
	       pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT;
}

-static inline bool pcie_cap_has_rtctl(const struct pci_dev *dev)
+bool pcie_cap_has_rtctl(const struct pci_dev *dev)
{
	int type = pci_pcie_type(dev);

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8abc843..40d5507 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1340,6 +1340,7 @@  int pci_save_state(struct pci_dev *dev)

 	pci_save_ltr_state(dev);
	pci_save_dpc_state(dev);
+	pci_save_aer_state(dev);
	return pci_save_vc_state(dev);
}
EXPORT_SYMBOL(pci_save_state);
@@ -1453,6 +1454,7 @@  void pci_restore_state(struct pci_dev *dev)
	pci_restore_dpc_state(dev);

 	pci_cleanup_aer_error_status_regs(dev);
+	pci_restore_aer_state(dev);

 	pci_restore_config_space(dev);

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9cb9938..268995b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -12,6 +12,7 @@  extern const unsigned char pcie_link_speed[];
extern bool pci_early_dump;

 bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
+bool pcie_cap_has_rtctl(const struct pci_dev *dev);

 /* Functions internal to the PCI core code */

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index b45bc47..7c41dec 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -448,6 +448,53 @@  int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
	return 0;
}

+
+void pci_save_aer_state(struct pci_dev *dev)
+{
+	struct pci_cap_saved_state *save_state;
+	u32 *cap;
+	int pos;
+
+	pos = dev->aer_cap;
+	if (!pos)
+		return;
+
+	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
+	if (!save_state)
+		return;
+
+	cap = &save_state->cap.data[0];
+	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, cap++);
+	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, cap++);
+	pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, cap++);
+	pci_read_config_dword(dev, pos + PCI_ERR_CAP, cap++);
+	if (pcie_cap_has_rtctl(dev))
+		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, cap++);
+}
+
+void pci_restore_aer_state(struct pci_dev *dev)
+{
+	struct pci_cap_saved_state *save_state;
+	u32 *cap;
+	int pos;
+
+	pos = dev->aer_cap;
+	if (!pos)
+		return;
+
+	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
+	if (!save_state)
+		return;
+
+	cap = &save_state->cap.data[0];
+	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, *cap++);
+	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, *cap++);
+	pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, *cap++);
+	pci_write_config_dword(dev, pos + PCI_ERR_CAP, *cap++);
+	if (pcie_cap_has_rtctl(dev))
+		pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, *cap++);
+}
+
void pci_aer_init(struct pci_dev *dev)
{
	dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
@@ -455,6 +502,18 @@  void pci_aer_init(struct pci_dev *dev)
	if (dev->aer_cap)
		dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);

+	/*
+	 * Since PCI_ERR_ROOT_COMMAND is only valid for root port and root
+	 * complex event collector, as per PCIe 4.0 section 7.8.4, interpret
+	 * the device/port type to determine the availability of additional
+	 * root port and root complex event collector register.
+	 */
+	if (pcie_cap_has_rtctl(dev))
+		pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR,
+					sizeof(u32) * 5);
+	else
+		pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR,
+					sizeof(u32) * 4);
	pci_cleanup_aer_error_status_regs(dev);
}

diff --git a/include/linux/aer.h b/include/linux/aer.h
index 514bffa..fa19e01 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -46,6 +46,8 @@  int pci_enable_pcie_error_reporting(struct pci_dev *dev);
int pci_disable_pcie_error_reporting(struct pci_dev *dev);
int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
+void pci_save_aer_state(struct pci_dev *dev);
+void pci_restore_aer_state(struct pci_dev *dev);
#else
static inline int pci_enable_pcie_error_reporting(struct pci_dev *dev)
{
@@ -63,6 +65,8 @@  static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
{
	return -EINVAL;
}
+static inline void pci_save_aer_state(struct pci_dev *dev) {}
+static inline void pci_restore_aer_state(struct pci_dev *dev) {}
#endif

 void cper_print_aer(struct pci_dev *dev, int aer_severity,