Re: [Xen-devel] [PATCH v4 2/5] vpci: fix deferral of long operations

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.11.18 at 12:57, <roger.pau@xxxxxxxxxx> wrote:
> Current logic to handle long running operations has two flaws:
> 
>  - hvm_io_pending is only used by Intel code, fix this by moving the
>    call to vpci_process_pending into handle_hvm_io_completion.

As mentioned before, the reference to Intel code is wrong here.
The main caller is handle_pio(), and the Intel specific one sits in
nested VMX code anyway, so is of basically no interest for the
purposes here.

> @@ -186,6 +183,9 @@ bool handle_hvm_io_completion(struct vcpu *v)
>      enum hvm_io_completion io_completion;
>      unsigned int id;
>  
> +    if ( has_vpci(d) && vpci_process_pending(v) )
> +        return false;

I think this would be the better place to raise the scheduler softirq.
vpci_process_pending() should indicated to its caller just whether
preemption is needed, but should not care how this is actually to
be effected. This is benign now, but might change if a second
caller would need adding.

> @@ -182,6 +185,7 @@ static void defer_map(struct domain *d, struct pci_dev 
> *pdev,
>      curr->vpci.mem = mem;
>      curr->vpci.cmd = cmd;
>      curr->vpci.rom_only = rom_only;
> +    raise_softirq(SCHEDULE_SOFTIRQ);
>  }

Why is this needed? The description doesn't mention it.

Jan



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