Re: x86 MD MSI/MSI-X implementation

[Matt Thomas <matt%3am-software.com@localhost>]

> On Apr 9, 2015, at 3:44 AM, Kengo NAKAHARA <k-nakahara%iij.ad.jp@localhost> wrote:
> 
> Hi,
> 
> I implement x86 MD MSI/MSI-X support code. Here is the patch:
>   http://www.netbsd.org/~knakahara/md-msi-msix/x86-md-msi-msix.patch
> 
> Furthermore, here is the usage example of if_wm:
>   http://www.netbsd.org/~knakahara/md-msi-msix/if_wm-msi-msix.patch
> 
> I believe this MD implementation help to decide the MI APIs.
> One of MI MSI/MSI-X API is dyoung@n.o's bus_msi(9),
>   http://mail-index.netbsd.org/tech-kern/2014/06/06/msg017209.html
> another is matt@n.o's API,
>   http://mail-index.netbsd.org/tech-kern/2011/08/05/msg011130.html
> The other is mine, above patch includes my API manual.
> 
> I want feedback from various device driver MSI/MSI-X implementations,
> such as usability, portablity, performance, and potential issues.
> So, I would like to commit above patch. If no one opposites, I commit
> above patch after one or two weeks.
> # Of course, I will commit by dividing each component.
> 
> Could you comment this implementation?

PCI_MSI_MSIX should be __HAVE_PCI_MSI_MSIX 

void *vih;

That should be pci_msix_handle_t or pci_msi_handle_t unless you want
still use pci_intr_handle_t.

+		mutex_enter(&cpu_lock);
+		error = intr_distribute(vih, affinity, NULL);
+		mutex_exit(&cpu_lock);


Why the cpu_lock?  shouldn't intr_distribute handle that itself?

This should a pci_intr_distribute and be done before the establish, not after.

Why do you assume you will only allocate one slot per msi/msix call?
Some device will use multiple contiguous slots so you have to alllocate
them as a set.