RE: [PATCH v2] Fix failure cleanup in EvtchnFifoAcquire

["Durrant, Paul" <pdurrant@xxxxxxxxxxxx>]

> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf
> Of Tu Dinh
> Sent: Friday, July 18, 2025 10:59 AM
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>; Owen Smith <owen.smith@xxxxxxxxx>;
> Durrant, Paul <pdurrant@xxxxxxxxxxxx>
> Subject: [EXTERNAL] [PATCH v2] Fix failure cleanup in EvtchnFifoAcquire
> 
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> 
> The current index is incremented before checking for failure:
> 
>     while (Index < ProcessorCount) {
>         Index++;
>         [...]
>         if (!NT_SUCCESS(status))
>             goto fail1;
>         Context->ControlBlockMdl[vcpu_id] = Mdl;
>     }
> 
> Make the main loop a normal for loop to avoid calling __FreePage on
> invalid PMDLs.
> 
> Signed-off-by: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>
> ---
>  src/xenbus/evtchn_fifo.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/src/xenbus/evtchn_fifo.c b/src/xenbus/evtchn_fifo.c
> index 1137dea..fd06ef4 100644
> --- a/src/xenbus/evtchn_fifo.c
> +++ b/src/xenbus/evtchn_fifo.c
> @@ -502,16 +502,13 @@ EvtchnFifoAcquire(
> 
>      ProcessorCount =
> KeQueryMaximumProcessorCountEx(ALL_PROCESSOR_GROUPS);
> 
> -    Index = 0;
> -    while (Index < ProcessorCount) {
> +    for (Index = 0; Index < ProcessorCount; Index++) {

Prevailing style uses while loops I think so stick with that for consistency, 
just move the increment down.

>          unsigned int        vcpu_id;
>          PFN_NUMBER          Pfn;
>          PHYSICAL_ADDRESS    Address;
> 
>          status = SystemProcessorVcpuId(Index, &vcpu_id);
> 
> -        Index++;
> -
>          if (status == STATUS_NOT_SUPPORTED)
>              continue;
> 
> --
> 2.50.1.windows.1
> 
> 
> 
> Ngoc Tu Dinh | Vates XCP-ng Developer
> 
> XCP-ng & Xen Orchestra - Vates solutions
> 
> web: https://vates.tech
>