Re: [Xen-devel] [PATCH V3 2/2] Xen/PCIback: Implement PCI flr/slot/bus reset with 'reset' SysFS attribute

[Pasi Kärkkäinen <pasik@xxxxxx>]

Hi,

On Fri, Jan 17, 2020 at 02:13:04PM -0500, Rich Persaud wrote:
>    On Aug 26, 2019, at 17:08, Pasi Kärkkäinen <pasik@xxxxxx> wrote:
> 
>      Hi,
>      On Mon, Oct 08, 2018 at 10:32:45AM -0400, Boris Ostrovsky wrote:
> 
>        On 10/3/18 11:51 AM, Pasi Kärkkäinen wrote:
> 
>          On Wed, Sep 19, 2018 at 11:05:26AM +0200, Roger Pau Monné wrote:
> 
>            On Tue, Sep 18, 2018 at 02:09:53PM -0400, Boris Ostrovsky wrote:
> 
>              On 9/18/18 5:32 AM, George Dunlap wrote:
> 
>                  On Sep 18, 2018, at 8:15 AM, Pasi Kärkkäinen <pasik@xxxxxx>
>                  wrote:
> 
>                  Hi,
> 
>                  On Mon, Sep 17, 2018 at 02:06:02PM -0400, Boris Ostrovsky
>                  wrote:
> 
>                    What about the toolstack changes? Have they been accepted?
>                    I vaguely
> 
>                    recall there was a discussion about those changes but
>                    don't remember how
> 
>                    it ended.
> 
>                  I don't think toolstack/libxl patch has been applied yet
>                  either.
> 
>                  "[PATCH V1 0/1] Xen/Tools: PCI reset using 'reset' SysFS
>                  attribute":
> 
>                  
> https://lists.xen.org/archives/html/xen-devel/2017-12/msg00664.html
> 
>                  "[PATCH V1 1/1] Xen/libxl: Perform PCI reset using 'reset'
>                  SysFS attribute":
> 
>                  
> https://lists.xen.org/archives/html/xen-devel/2017-12/msg00663.html
> 
>              Will this patch work for *BSD? Roger?
> 
>            At least FreeBSD don't support pci-passthrough, so none of this
>            works
> 
>            ATM. There's no sysfs on BSD, so much of what's in libxl_pci.c
>            will
> 
>            have to be moved to libxl_linux.c when BSD support is added.
> 
>          Ok. That sounds like it's OK for the initial pci 'reset'
>          implementation in xl/libxl to be linux-only..
> 
>        Are these two patches still needed? ISTR they were  written originally
> 
>        to deal with guest trying to use device that was previously assigned
>        to
> 
>        another guest. But pcistub_put_pci_dev() calls
> 
>        __pci_reset_function_locked() which first tries FLR, and it looks like
> 
>        it was added relatively recently.
> 
>      Replying to an old thread.. I only now realized I forgot to reply to
>      this message earlier.
>      afaik these patches are still needed. Håkon (CC'd) wrote to me in
>      private that
>      he gets a (dom0) Linux kernel crash if he doesn't have these patches
>      applied.
>      Here are the links to both the linux kernel and libxl patches:
>      "[Xen-devel] [PATCH V3 0/2] Xen/PCIback: PCI reset using 'reset' SysFS
>      attribute":
>      https://lists.xen.org/archives/html/xen-devel/2017-12/msg00659.html
>      [Note that PATCH V3 1/2 "Drivers/PCI: Export pcie_has_flr() interface"
>      is already applied in upstream linux kernel, so it's not needed anymore]
>      "[Xen-devel] [PATCH V3 2/2] Xen/PCIback: Implement PCI flr/slot/bus
>      reset with 'reset' SysFS attribute":
>      https://lists.xen.org/archives/html/xen-devel/2017-12/msg00661.html
>      "[Xen-devel] [PATCH V1 0/1] Xen/Tools: PCI reset using 'reset' SysFS
>      attribute":
>      https://lists.xen.org/archives/html/xen-devel/2017-12/msg00664.html
>      "[Xen-devel] [PATCH V1 1/1] Xen/libxl: Perform PCI reset using 'reset'
>      SysFS attribute":
>      https://lists.xen.org/archives/html/xen-devel/2017-12/msg00663.html
> 
>    [dropping Linux mailing lists]
>    What is required to get the Xen patches merged?  Rebasing against Xen
>    master?  OpenXT has been carrying a similar patch for many years and we
>    would like to move to an upstream implementation.  Xen users of PCI
>    passthrough would benefit from more reliable device reset.
>      2017 thread, including OpenXT
>    patch: [1]https://lists.gt.net/xen/devel/492945
>      2017-2019 thread: [2]https://lists.gt.net/xen/devel/532648
>

Yes, rebasing the kernel patch against the current Linux kernel, and also 
rebasing the libxl bits against current master/staging.
That should be a good start!

I'd like to see the reset functionality merged aswell.


>    Rich
> 


Thanks,

-- Pasi


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