Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1600430

Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig

Show all headers | View raw

On Thu, 2 Mar 2017, Andi Kleen wrote:
> +struct pci_ops pci_mmconfig_ops = {
> +	.read = pci_mmconfig_read,
> +	.write = pci_mmconfig_write,
> +};
> +
> +/* Force all config accesses to go through mmconfig. */
> +int pci_bus_force_mmconfig(struct pci_bus *bus)
> +{
> +	if (!raw_pci_ext_ops)
> +		return -1;

We have error defines. That aside, the weak version of this returns 0,
i.e. success, but here you return fail. Consistency is overrated, right?

> +	bus->ops = &pci_mmconfig_ops;

What guarantees that raw_pci_ext_ops == pci_mmcfg? Nothing as far as I can
tell. So that function name is nonsensical. It does not force anything.

And the way how this function is used is a horrible hack. It's called from
a random driver at some random point in time.

The proper solution is to identify the bus at the point where the bus is
discovered and switch it to mmconfig if possible.

Thanks,

	tglx

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 1/4] pci: Allow lockless access path to PCI mmconfig Andi Kleen <andi@firstfloor.org> - 2017-03-03 03:20 +0100
  [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <andi@firstfloor.org> - 2017-03-03 06:10 +0100
    Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 15:00 +0100
      Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <ak@linux.intel.com> - 2017-03-14 16:50 +0100
        Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 17:50 +0100
          Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <ak@linux.intel.com> - 2017-03-14 18:10 +0100
            Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 19:00 +0100
              Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Bjorn Helgaas <helgaas@kernel.org> - 2017-03-14 20:50 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <andi@firstfloor.org> - 2017-03-15 03:30 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Bjorn Helgaas <helgaas@kernel.org> - 2017-03-15 04:00 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-15 11:10 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Bjorn Helgaas <helgaas@kernel.org> - 2017-03-15 15:20 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <andi@firstfloor.org> - 2017-03-16 01:10 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-16 23:50 +0100
  Re: [PATCH 1/4] pci: Allow lockless access path to PCI mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 14:10 +0100
  Re: [PATCH 1/4] pci: Allow lockless access path to PCI mmconfig "H. Peter Anvin" <hpa@zytor.com> - 2017-03-14 18:30 +0100

csiph-web