Re: [PATCH v4 1/4] vpci: Use pervcpu ranges for BAR mapping

[Jan Beulich <jbeulich@xxxxxxxx>]

On 06.04.2026 21:11, Stewart Hildebrand wrote:
> From: Mykyta Poturai <Mykyta_Poturai@xxxxxxxx>
> 
> There is no need to store ranges for each PCI device, as they are only
> used during the mapping/unmapping process and can be reused for each
> device. This also allows to avoid the need to allocate and destroy
> rangesets for each device.
> 
> Move the rangesets from struct vpci_bar to struct vpci_vcpu and perform
> (de-)allocation with vcpu (de-)allocation. Introduce RANGESET_DESTROY()
> macro to free a rangeset and set the pointer to NULL.
> 
> Amends: 622bdd962822 ("vpci/header: handle p2m range sets per BAR")
> Signed-off-by: Mykyta Poturai <mykyta_poturai@xxxxxxxx>
> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
> ---
> It seems a bit awkward to introduce various vpci vcpu alloc/dealloc
> functions here only to undo most of it in the next patch. Thoughts on
> folding the next patch into this one?
> 
> v3->v4:
> * no change

There are some complexities here due to the patch being part of two series.
Once Mykyta re-submits the SR-IOV series, we'll have two (likely diverging)
v4-s. Already here ...

> v2->v3:
> * new patch in this series, borrowed from [1]
> * add Amends tag
> * remove unused variable i due to rebasing over 998060dd9101 ("vPCI:
>   move vpci_init_capabilities() to a separate file")
> * enclose entire struct vpci_vcpu inside #ifdef __XEN__
> * s/bar_mem/mem/
> * use ARRAY_SIZE
> * put init/destroy in functions
> * only allocate for domains with vPCI and idle domain
> * replace 'if ( !mem ) continue;' with ASSERT

... the v3 there has one more item on this ChangeLog list ("* synced with
BAR write with memory decoding enabled series[1]"), albeit maybe (now that I
read it again) this merely is the counterpart of the first bullet point here.
It would be clearer if there the other series' title was supplied verbatim
and in quotes.

Jan