Mailing List Archive: [PATCH v2 3/4] x86/shim: don't permit HVM and PV_SHIM

[PATCH v2 3/4] x86/shim: don't permit HVM and PV_SHIM_EXCLUSIVE at the same time

Sep 16, 2020, 6:08 AM

Post #1 of 3 (45 views)

This combination doesn't really make sense (and there likely are more);
in particular even if the code built with both options set, HVM guests
wouldn't work (and I think one wouldn't be able to create one in the
first place). The alternative here would be some presumably intrusive
#ifdef-ary to get this combination to actually build (but still not
work) again.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Restore lost default setting.

--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -23,7 +23,7 @@ config X86
select HAS_PDX
select HAS_SCHED_GRANULARITY
select HAS_UBSAN
- select HAS_VPCI if !PV_SHIM_EXCLUSIVE && HVM
+ select HAS_VPCI if HVM
select NEEDS_LIBELF
select NUMA

@@ -90,8 +90,9 @@ config PV_LINEAR_PT
If unsure, say Y.

config HVM
- def_bool !PV_SHIM_EXCLUSIVE
- prompt "HVM support"
+ bool "HVM support"
+ depends on !PV_SHIM_EXCLUSIVE
+ default y
---help---
Interfaces to support HVM domains. HVM domains require hardware
virtualisation extensions (e.g. Intel VT-x, AMD SVM), but can boot

Re: [PATCH v2 3/4] x86/shim: don't permit HVM and PV_SHIM_EXCLUSIVE at the same time [ In reply to ]

roger.pau at citrix

Oct 8, 2020, 7:52 AM

Post #2 of 3 (44 views)

Permalink

On Wed, Sep 16, 2020 at 03:08:00PM +0200, Jan Beulich wrote:
> This combination doesn't really make sense (and there likely are more);
> in particular even if the code built with both options set, HVM guests
> wouldn't work (and I think one wouldn't be able to create one in the
> first place). The alternative here would be some presumably intrusive
> #ifdef-ary to get this combination to actually build (but still not
> work) again.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

I can see the desire for being able to remove code, and the point
Andrew made about one option not making another disappear in a
completely different menu section.

Yet I don't see how to converge the two together, unless we completely
change our menu layouts, and even then I'm not sure I see how we could
structure this. Hence:

Acked-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks, Roger.

Re: [PATCH v2 3/4] x86/shim: don't permit HVM and PV_SHIM_EXCLUSIVE at the same time [ In reply to ]

jbeulich at suse

Oct 13, 2020, 3:30 AM

Post #3 of 3 (44 views)

Permalink

On 08.10.2020 16:52, Roger Pau Monné wrote:
> On Wed, Sep 16, 2020 at 03:08:00PM +0200, Jan Beulich wrote:
>> This combination doesn't really make sense (and there likely are more);
>> in particular even if the code built with both options set, HVM guests
>> wouldn't work (and I think one wouldn't be able to create one in the
>> first place). The alternative here would be some presumably intrusive
>> #ifdef-ary to get this combination to actually build (but still not
>> work) again.
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> I can see the desire for being able to remove code, and the point
> Andrew made about one option not making another disappear in a
> completely different menu section.
>
> Yet I don't see how to converge the two together, unless we completely
> change our menu layouts, and even then I'm not sure I see how we could
> structure this. Hence:
>
> Acked-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks.

Andrew - are you okay with this going in then? Or if not, do you have
any thoughts towards an alternative approach?

Jan