On Wed, Oct 27, 2021 at 11:59:47AM +0000, Oleksandr Andrushchenko wrote: > Hi, Roger! > > On 27.10.21 13:17, Oleksandr Andrushchenko wrote: > > Hi, Roger! > > > > On 13.10.21 16:51, Roger Pau Monné wrote: > >> On Thu, Sep 30, 2021 at 10:52:15AM +0300, Oleksandr Andrushchenko wrote: > >>> From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com> > >>> > >>> This is in preparation for dynamic assignment of the vPCI register > >>> handlers depending on the domain: hwdom or guest. > >>> The need for this step is that it is easier to have all related > >>> functionality > >>> put at one place. When the subsequent patches add decisions on which > >>> handlers to install, e.g. hwdom or guest handlers, then this is easily > >>> achievable. > >> Won't it be possible to select the handlers to install in init_bars > >> itself? > > It is possible > >> Splitting it like that means you need to iterate over the numbers of > >> BARs twice (one in add_bar_handlers and one in init_bars), which makes > >> it more likely to introduce errors or divergences. > >> > >> Decoupling the filling of vpci_bar data with setting the handlers > >> seems slightly confusing. > > Ok, I won't introduce add_bar_handlers, thus rendering this patch useless. > > I'll drop it and re-work the upcoming patches with this respect > On the other hand after thinking a bit more. > What actually init_bars do? > 1. Runs once per each pdev (__init?) > 2. Sizes the BARs and detects their type, sets up pdev->vpci->header BAR > values > 3. Adds register handlers. > > For DomU we only need 3), so we can setup guest handlers.
I think you assume that there will always be a hardware domain with vPCI enabled that will get the device assigned and thus init_bars will be executed prior to assigning to a domU. But what about dom0less, or when using a classic PV dom0? In that case the device won't get assigned to a hardware domain with vPCI support, so the vpci structure won't be allocated or filled, and hence init_bars would have to be executed when assigning to a domU. Thanks, Roger.
