Re: [Xen-devel] [PATCH v2 14/16] x86: make entry point code build when !CONFIG_PV

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 02.11.18 at 14:08, <wei.liu2@xxxxxxxxxx> wrote:
> On Mon, Oct 29, 2018 at 09:03:18AM -0600, Jan Beulich wrote:
>> >>> On 19.10.18 at 16:28, <wei.liu2@xxxxxxxxxx> wrote:
>> > @@ -548,10 +550,14 @@ ENTRY(ret_from_intr)
>> >          GET_CURRENT(bx)
>> >          testb $3, UREGS_cs(%rsp)
>> >          jz    restore_all_xen
>> > +#ifdef CONFIG_PV
>> >          movq  VCPU_domain(%rbx), %rax
>> >          cmpb  $0, DOMAIN_is_32bit_pv(%rax)
>> >          je    test_all_events
>> >          jmp   compat_test_all_events
>> > +#else
>> > +        BUG
>> > +#endif
>> 
>> Hmm, not sure here (and elsewhere): Another option is to
>> streamline execution by replacing the conditional branch with an
>> unconditional one in the !PV case. Andrew, do you have any
>> thoughts either way?
> 
> My original thought was to catch potential issues in Xen code which
> messes up with the permission level.  Using unconditional jump is fine
> by me, too. But in that case I will seek to at least add an assertion
> for debug build.

Assertion additions are definitely fine with me.

Jan



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