Re: [PATCH v3] PCI/ERR: Use pcie_aer_is_native() to judge whether OS owns AER

[Zhuo Chen]

On 7/26/22 1:35 PM, Zhuo Chen wrote:
> On 7/26/22 9:02 PM, Sathyanarayanan Kuppuswamy wrote:
> > On 7/26/22 8:53 PM, Zhuo Chen wrote:
> > > Use pcie_aer_is_native() in place of "host->native_aer ||
> > > pcie_ports_native" to judge whether OS has native control of AER
> > > in pcie_do_recovery().
> > >
> > > Replace "dev->aer_cap && (pcie_ports_native || host->native_aer)" in
> > > get_port_device_capability() with pcie_aer_is_native(), which has no
> > > functional changes.
> > >
> > > Signed-off-by: Zhuo Chen <chenzhuo.1@xxxxxxxxxxxxx>
> > > ---
> >
> > Patch looks better now. It looks like following two changes
> > can also be replaced with pcie_aer_is_native() check.
> >
> > drivers/pci/pcie/aer.c:1407:    if ((host->native_aer || 
> > pcie_ports_native) && aer) {
> > drivers/pci/pcie/aer.c:1426:    if ((host->native_aer || 
> > pcie_ports_native) && aer) {
>
> Good advice. But I wonder is there a scenario that dev->rcec ("root") is 
> NULL meanwhile dev->aer_cap is not NULL? If so, replace 
> "(host->native_aer || pcie_ports_native) && aer" with 
> pcie_aer_is_native() will change original function.
Do you mean changing "if ((host->native_aer || pcie_ports_native) && 
aer)" into "if (pcie_aer_is_native(dev) && aer)" ?
I thought changing into "if (pcie_aer_is_native(dev))" before.

One another doubt. Not every pci device support aer. When dev->aer_cap 
is NULL and root->aer_cap is not NULL in aer_root_reset(), 
pcie_aer_is_native() will return false and OS cannot operate root 
register. It's different from just using "(host->native_aer || 
pcie_ports_native)".

Or we can change "if ((host->native_aer || pcie_ports_native) && aer)" 
into "if (pcie_aer_is_native(root))". But in this way, argument NULL 
pointer check should be added in pcie_aer_is_native().

> > > Changelog:
> > > v3:
> > > - Simplify why we use pcie_aer_is_native().
> > > - Revert modification of pci_aer_clear_nonfatal_status() and comments.
> > > v2:
> > > - Add details and note in commit log.
> > > ---
> > >   drivers/pci/pcie/err.c          | 3 +--
> > >   drivers/pci/pcie/portdrv_core.c | 3 +--
> > >   2 files changed, 2 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> > > index 0c5a143025af..121a53338e44 100644
> > > --- a/drivers/pci/pcie/err.c
> > > +++ b/drivers/pci/pcie/err.c
> > > @@ -184,7 +184,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev 
> > > *dev,
> > >       int type = pci_pcie_type(dev);
> > >       struct pci_dev *bridge;
> > >       pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> > > -    struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> > >       /*
> > >        * If the error was detected by a Root Port, Downstream Port, 
> > > RCEC,
> > > @@ -243,7 +242,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev 
> > > *dev,
> > >        * it is responsible for clearing this status.  In that case, the
> > >        * signaling device may not even be visible to the OS.
> > >        */
> > > -    if (host->native_aer || pcie_ports_native) {
> > > +    if (pcie_aer_is_native(dev)) {
> > >           pcie_clear_device_status(dev);
> > >           pci_aer_clear_nonfatal_status(dev);
> > >       }
> > > diff --git a/drivers/pci/pcie/portdrv_core.c 
> > > b/drivers/pci/pcie/portdrv_core.c
> > > index 604feeb84ee4..98c18f4a01b2 100644
> > > --- a/drivers/pci/pcie/portdrv_core.c
> > > +++ b/drivers/pci/pcie/portdrv_core.c
> > > @@ -221,8 +221,7 @@ static int get_port_device_capability(struct 
> > > pci_dev *dev)
> > >       }
> > >   #ifdef CONFIG_PCIEAER
> > > -    if (dev->aer_cap && pci_aer_available() &&
> > > -        (pcie_ports_native || host->native_aer)) {
> > > +    if (pcie_aer_is_native(dev) && pci_aer_available()) {
> > >           services |= PCIE_PORT_SERVICE_AER;
> > >           /*
>
> Thanks,
> Zhuo Chen

--
Thanks,
Zhuo Chen