Re: Weak x86 aliases

2018-12-30 Thread Jason Thorpe
> On Dec 28, 2018, at 10:14 AM, Mathew, Cherry G. wrote: > > ic, this probably explains why it's used sparingly so far. Thanks for the > explanation. I'll try to educate myself on this wrt enabling this for modload. We use weak symbols all over the place in user space. It's just that the

Re: Weak x86 aliases

2018-12-29 Thread Martin Husemann
On Sat, Dec 29, 2018 at 01:41:08AM +0530, Mathew, Cherry G. wrote: > Hotpatching will be ugly because we need both versions - for eg: > xen_intr_register_xname() aliases to intr_register_xname() in DomU and > Dom0 but we need both in the case of PVHVM. I don't understand why you need two

Re: Weak x86 aliases

2018-12-29 Thread Maxime Villard
Le 29/12/2018 à 08:40, Cherry G.Mathew a écrit : Maxime Villard writes: Le 28/12/2018 à 15:06, Cherry G.Mathew a écrit : Maxime Villard writes: Le 28/12/2018 à 14:57, Cherry G.Mathew a écrit : Maxime Villard writes: Introduce a weak alias method of exporting different implementations of

Re: Weak x86 aliases

2018-12-28 Thread Cherry G . Mathew
Maxime Villard writes: > Le 28/12/2018 à 15:06, Cherry G.Mathew a écrit : >> Maxime Villard writes: >>> Le 28/12/2018 à 14:57, Cherry G.Mathew a écrit : Maxime Villard writes: >> Introduce a weak alias method of exporting different implementations >> of the same API. > >

Re: Weak x86 aliases

2018-12-28 Thread Cherry G . Mathew
John Nemeth writes: > On Dec 28, 11:52pm, "Mathew, Cherry G." wrote: > } On December 28, 2018 9:54:11 PM GMT+05:30, John Nemeth > wrote: > } >On Dec 28, 7:36pm, "Cherry G.Mathew" wrote: > } >} Maxime Villard writes: > } >} > Le 28/12/2018 �� 14:57, Cherry G.Mathew a ��crit : > } >} >> Maxime

Re: Weak x86 aliases

2018-12-28 Thread Jason Thorpe
> On Dec 28, 2018, at 6:44 PM, John Nemeth wrote: > > However, having said that, I suspect that your work with PVHVM > (and presumably PVH after that) will make the idea of having seperate > modules for Xen obsolete. I.e. it appears to me that we're headed > to a world where a single

Re: Weak x86 aliases

2018-12-28 Thread Jason Thorpe
> On Dec 28, 2018, at 1:32 PM, Paul Goyette wrote: > > The in-kernel linker doesn't deal with weak symbols at all. It would > need a lot of thought to get it right. For example, if module A > (containing a weak reference) gets loaded, its weak references don't > resolve. Then module B gets

Re: Weak x86 aliases

2018-12-28 Thread Paul Goyette
On Fri, 28 Dec 2018, Cherry G.Mathew wrote: I think I'll revert these for now, because PVHVM doesn't/shouldn't use them anyway, but I'd like to know how to fix this properly. modload not working due to __weak_alias() sounds like something we don't do properly in the modload path. The

Re: Weak x86 aliases

2018-12-28 Thread Mathew, Cherry G.
Hotpatching will be ugly because we need both versions - for eg: xen_intr_register_xname() aliases to intr_register_xname() in DomU and Dom0 but we need both in the case of PVHVM. So the other option is function pointers - but this will require re-prototyping all function names that PVHVM

Re: Weak x86 aliases

2018-12-28 Thread Martin Husemann
On Fri, Dec 28, 2018 at 07:36:12PM +0530, Cherry G.Mathew wrote: > > There is a check in kobj_sym_lookup(): > > > > 926 case STB_WEAK: > > 927 kobj_error(ko, "weak symbols not supported"); > > 928 return EINVAL; > > > > To resolve correctly I guess we need

Re: Weak x86 aliases

2018-12-28 Thread Mathew, Cherry G.
On December 28, 2018 9:54:11 PM GMT+05:30, John Nemeth wrote: >On Dec 28, 7:36pm, "Cherry G.Mathew" wrote: >} Maxime Villard writes: >} > Le 28/12/2018 �� 14:57, Cherry G.Mathew a ��crit : >} >> Maxime Villard writes: >} Introduce a weak alias method of exporting different

Re: Weak x86 aliases

2018-12-28 Thread Mathew, Cherry G.
On December 28, 2018 11:28:01 PM GMT+05:30, Jason Thorpe wrote: > >> On Dec 28, 2018, at 9:50 AM, Mathew, Cherry G. wrote: >> >> That seems like a dependency burden on people developing new >features. I can't tell if modload is the only way to get NVMM to run. >If it is, then ok. If not, then

Re: Weak x86 aliases

2018-12-28 Thread Mathew, Cherry G.
On December 28, 2018 9:54:11 PM GMT+05:30, John Nemeth wrote: >On Dec 28, 7:36pm, "Cherry G.Mathew" wrote: >} Maxime Villard writes: >} > Le 28/12/2018 �� 14:57, Cherry G.Mathew a ��crit : >} >> Maxime Villard writes: >} Introduce a weak alias method of exporting different

Re: Weak x86 aliases

2018-12-28 Thread Mathew, Cherry G.
On December 28, 2018 8:40:11 PM GMT+05:30, Jason Thorpe wrote: > >> On Dec 28, 2018, at 6:06 AM, Cherry G.Mathew wrote: >> >> I don't like the imperative in your tone. NVMM is the user of >modloader, >> not PVHVM. So if you feel like your usecase needs fixing, I'd say >it's >> your problem - or

Re: Weak x86 aliases

2018-12-28 Thread Mathew, Cherry G.
On December 28, 2018 7:58:10 PM GMT+05:30, Maxime Villard wrote: >Le 28/12/2018 à 15:06, Cherry G.Mathew a écrit : >> Maxime Villard writes: >>> Le 28/12/2018 à 14:57, Cherry G.Mathew a écrit : Maxime Villard writes: >> Introduce a weak alias method of exporting different

Re: Weak x86 aliases

2018-12-28 Thread Cherry G . Mathew
Cherry G. Mathew writes: [...] > I think I'll revert these for now, PS: I'm in transit and probably not the best time to do this - if you feel like it's urgent enough, please feel free to rollback. I'll fix breakage on my end once the dust settles. I'll be in a commitable place in ~48hrs.

Re: Weak x86 aliases

2018-12-28 Thread Jason Thorpe
> On Dec 28, 2018, at 6:06 AM, Cherry G.Mathew wrote: > > I don't like the imperative in your tone. NVMM is the user of modloader, > not PVHVM. So if you feel like your usecase needs fixing, I'd say it's > your problem - or don't use modules, but see below. ...but as the person who committed

Re: Weak x86 aliases

2018-12-28 Thread Cherry G . Mathew
Maxime Villard writes: > Le 28/12/2018 à 14:57, Cherry G.Mathew a écrit : >> Maxime Villard writes: Introduce a weak alias method of exporting different implementations of the same API. >>> >>> Please revert or fix this change. >> >> I'm not sure what the fix is - do you have a

Re: Weak x86 aliases

2018-12-28 Thread Maxime Villard
Le 28/12/2018 à 15:06, Cherry G.Mathew a écrit : Maxime Villard writes: Le 28/12/2018 à 14:57, Cherry G.Mathew a écrit : Maxime Villard writes: Introduce a weak alias method of exporting different implementations of the same API. Please revert or fix this change. I'm not sure what the

Re: Weak x86 aliases

2018-12-28 Thread Maxime Villard
Le 28/12/2018 à 14:57, Cherry G.Mathew a écrit : Maxime Villard writes: Introduce a weak alias method of exporting different implementations of the same API. Please revert or fix this change. I'm not sure what the fix is - do you have a suggestion ? either re-apply it without using weak

Re: Weak x86 aliases

2018-12-28 Thread Cherry G . Mathew
Maxime Villard writes: >> Introduce a weak alias method of exporting different implementations >> of the same API. > > Please revert or fix this change. I'm not sure what the fix is - do you have a suggestion ? > The kernel modules that use these functions can't be modloaded > anymore,