Re: [Xen-devel] Xen optimization

[Milan Boberic <milanboberic94@xxxxxxxxx>]

Hi,

> Don't interrupt _come_ from hardware and go/are routed to
> hypervisor/os/app?
Yes they do, sorry, I reversed the order because I'm a newbie :) .

> Would you mind to explain what is the triple timer counter?
On this link on page 342 is explanation.

> This is not the official Xen repository and look like patches have been 
> applied on top. I am afraid, I am not going to be able help here. Could you 
> do the same experiment with Xen 4.11?

I think I have to get Xen from Xilinx because I use board that has
Zynq Ultrascale. Stefano sent branch with Xen 4.11 so I built with it.

> This could also means that wfi is not used by the guest or you never go to 
> the idle vCPU.
Right.

> This is definitely wrong. Can you please also post the full host device
> tree with your modifications that you are using for Xen and Dom0?  You
> should have something like:
>
>         timer@ff110000 {
>             compatible = "cdns,ttc";
>             interrupt-parent = <0x2>;
>             interrupts = <0x0 0x24 0x4 0x0 0x25 0x4 0x0 0x26 0x4>;
>             reg = <0x0 0xff110000 0x0 0x1000>;
>             timer-width = <0x20>;
>             power-domains = <0x3b>;
>             xen,passthrough;
>         };
> For each of the nodes of the devices you are assigning to the DomU.

I put
&ttc0 {
   xen,passthrough = <0x1>;
};
because when I was making bm app I was following this guide. Now I see
it's wrong. When I copied directly:
timer@ff110000 {
            compatible = "cdns,ttc";
            interrupt-parent = <0x2>;
            interrupts = <0x0 0x24 0x4 0x0 0x25 0x4 0x0 0x26 0x4>;
            reg = <0x0 0xff110000 0x0 0x1000>;
            timer-width = <0x20>;
            power-domains = <0x3b>;
            xen,passthrough;
        };
in to the xen-overlay.dtsi file it resulted an error during
device-tree build. I modified it a little bit so I can get successful
build, there are all device-tree files included in attachment. I'm not
sure how to set this passthrough properly, if you could take a look at
those files in attachment I'd be more then grateful.

> It's here: 
> https://github.com/Xilinx/xen/blob/xilinx/stable-4.9/xen/arch/arm/vgic.c#L462
Oh, about that. I sent you wrong branch, I was using Xen 4.10. Anyway
now I moved to Xen 4.11 like you suggested and applied your patch and
Dario's also.

Okay, now when I want to xl create my domU (bare-metal app) I get error:

Parsing config from timer.cfg
(XEN) IRQ 68 is already used by domain 0
libxl: error: libxl_create.c:1354:domcreate_launch_dm: Domain 1:failed
give domain access to irq 68: Device or resource busy
libxl: error: libxl_domain.c:1034:libxl__destroy_domid: Domain
1:Non-existant domain
libxl: error: libxl_domain.c:993:domain_destroy_callback: Domain
1:Unable to destroy guest
libxl: error: libxl_domain.c:920:domain_destroy_cb: Domain
1:Destruction of domain failed

I guess my modifications of:
timer@ff110000 {
            compatible = "cdns,ttc";
            interrupt-parent = <0x2>;
            interrupts = <0x0 0x24 0x4 0x0 0x25 0x4 0x0 0x26 0x4>;
            reg = <0x0 0xff110000 0x0 0x1000>;
            timer-width = <0x20>;
            power-domains = <0x3b>;
            xen,passthrough;
        };
are not correct. I tried to change interrupts to:
 interrupts = <0x0 0x44 0x4 0x0 0x45 0x4 0x0 0x46 0x4>;
because if you check here on page 310 interrupts for TTC0 are 68:70.
But that didn't work either I still get same error.

I also tried to change xen,passthrough; line with:
xen,passthrough = <0x1>;
but also without success, still the same error.

Are you sure about this line:
reg = <0x0 0xff110000 0x0 0x1000>;   ?
Or it should be like this?
 reg = <0x0 0xff110000 0x1000>;

I also included xl dmesg and dmesg in attachments (after xl create of bm app).

Thanks in advance!

Milan

Attachment: device-tree.bbappend.txt
Description: Text document

Attachment: xl dmesg.txt
Description: Text document

Attachment: system-user.dtsi.txt
Description: Text document

Attachment: dmesg.txt
Description: Text document

Attachment: xen-overlay.dtsi.txt
Description: Text document

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel