On Mon, Jul 13, 2020 at 1:13 PM Wei Liu <wei....@kernel.org> wrote:
>
> On Mon, Jul 13, 2020 at 01:10:50AM +0200, Sedat Dilek wrote:
> > When using Clang's Integrated Assembler (LLVM_IAS=1) we fell over
> > ClangBuiltLinux (CBL) issue #1043 where Jian Cai provided a fix.
> >
> > With Jian's fix applied another issue raised up when CONFIG_HYPERV=m.
> >
> > It turned out that the conversion of vectors to IDTENTRY_SYSVEC in
> > case of CONFIG_HYPERV was incomplete and fails with a build error:
> >
> > <instantiation>:9:6: error: expected absolute expression
> > .if HYPERVISOR_REENLIGHTENMENT_VECTOR == 3
> > ^
> > <instantiation>:1:1: note: while in macro instantiation
> > idtentry HYPERVISOR_REENLIGHTENMENT_VECTOR
> > asm_sysvec_hyperv_reenlightenment sysvec_hyperv_reenlightenment
> > has_error_code=0
> > ^
> > ./arch/x86/include/asm/idtentry.h:627:1: note: while in macro instantiation
> > idtentry_sysvec HYPERVISOR_REENLIGHTENMENT_VECTOR
> > sysvec_hyperv_reenlightenment;
> > ^
> > <instantiation>:9:6: error: expected absolute expression
> > .if HYPERVISOR_STIMER0_VECTOR == 3
> > ^
> > <instantiation>:1:1: note: while in macro instantiation
> > idtentry HYPERVISOR_STIMER0_VECTOR asm_sysvec_hyperv_stimer0
> > sysvec_hyperv_stimer0 has_error_code=0
> > ^
> > ./arch/x86/include/asm/idtentry.h:628:1: note: while in macro instantiation
> > idtentry_sysvec HYPERVISOR_STIMER0_VECTOR sysvec_hyperv_stimer0;
>
> Hmm... Interesting. GCC never complained. Guests are perhaps broken in a
> rather subtle way.
>
> >
> > I and Nathan double-checked the hyperv(isor) vectors:
> >
> > $ rg --no-heading
> > "HYPERVISOR_REENLIGHTENMENT_VECTOR|HYPERVISOR_STIMER0_VECTOR"
> > $ rg --no-heading "HYPERV_REENLIGHTENMENT_VECTOR|HYPERV_STIMER0_VECTOR"
> >
> > Fix these typos in arch/x86/include/asm/idtentry.h:
> >
> > HYPERVISOR_REENLIGHTENMENT_VECTOR -> HYPERV_REENLIGHTENMENT_VECTOR
> > HYPERVISOR_STIMER0_VECTOR -> HYPERV_STIMER0_VECTOR
> >
> > For more details see CBL issue #1088.
> >
> > With both fixes applied I was able to build/assemble with a snapshot
> > version of LLVM/Clang from Debian/experimental.
>
> I think the issue found here is independent of the other. This patch
> shouldn't need to wait for the other to land.
>
Yes, this one is - and can land - independently.
Without Jian's fix and CONFIG_HYPERV=m we have not seen the issue.
> >
> > Cc: Jian Cai <caij2...@gmail.com>
> > Cc: clang-built-li...@googlegroups.com
> > Reviewed-by: Nathan Chancellor <natechancel...@gmail.com>
> > Fixes: a16be368dd3f ("x86/entry: Convert various hypervisor vectors to
> > IDTENTRY_SYSVEC")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1088
> > Signed-off-by: Sedat Dilek <sedat.di...@gmail.com>
> > ---
> > arch/x86/include/asm/idtentry.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/idtentry.h
> > b/arch/x86/include/asm/idtentry.h
> > index 513eb2ccbdbf..a811f6c6cf15 100644
> > --- a/arch/x86/include/asm/idtentry.h
> > +++ b/arch/x86/include/asm/idtentry.h
> > @@ -624,8 +624,8 @@ DECLARE_IDTENTRY_SYSVEC(POSTED_INTR_NESTED_VECTOR,
> > sysvec_kvm_posted_intr_nested
> >
> > #if IS_ENABLED(CONFIG_HYPERV)
> > DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,
> > sysvec_hyperv_callback);
> > -DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_REENLIGHTENMENT_VECTOR,
> > sysvec_hyperv_reenlightenment);
> > -DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_STIMER0_VECTOR,
> > sysvec_hyperv_stimer0);
> > +DECLARE_IDTENTRY_SYSVEC(HYPERV_REENLIGHTENMENT_VECTOR,
> > sysvec_hyperv_reenlightenment);
> > +DECLARE_IDTENTRY_SYSVEC(HYPERV_STIMER0_VECTOR,
> > sysvec_hyperv_stimer0);
>
> Reviewed-by: Wei Liu <wei....@kernel.org>
>
Thanks for your review.
- Sedat -
> Thomas, can you pick this up for 5.8? Thanks.
>
> Wei.
