| Message ID | 20191221235049.4928-1-liuwe@microsoft.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | x86/hyperv: change hv_tlb_flush_ex to fix clang build | expand |
On 22.12.2019 00:50, Wei Liu wrote: > Clang complains: > > In file included from synic.c:15: > /builds/xen-project/xen/xen/include/asm/guest/hyperv-tlfs.h:900:18: error: field 'hv_vp_set' with variable sized type 'struct hv_vpset' not at the end of a struct or class is a GNU extension [-Werror,-Wgnu-variable-sized-type-not-at-end] > struct hv_vpset hv_vp_set; > ^ I'm surprised gcc does not complain. > 1 error generated. > /builds/xen-project/xen/xen/Rules.mk:198: recipe for target 'synic.o' failed > make[6]: *** [synic.o] Error 1 > > Drop the last variable size array from hv_tlb_flush_ex for now to fix > clang builds. Why "for now"? The field is illegal there, and I can't see a way to make it legal. To know its actual place in memory you need to know the number of elements in bank_contents[], i.e. having the field if the compiler erroneously accepted it would mean wrong code to get generated (silently). > --- a/xen/include/asm-x86/guest/hyperv-tlfs.h > +++ b/xen/include/asm-x86/guest/hyperv-tlfs.h > @@ -893,12 +893,11 @@ struct hv_tlb_flush { > u64 gva_list[]; > } __packed; > > -/* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */ > +/* HvFlushVirtualAddressSpaceEx hypercall */ > struct hv_tlb_flush_ex { > u64 address_space; > u64 flags; > struct hv_vpset hv_vp_set; > - u64 gva_list[]; Rather than outright removing the line, keep it as a comment? Jan
On Mon, Dec 23, 2019 at 10:53:29AM +0100, Jan Beulich wrote: > On 22.12.2019 00:50, Wei Liu wrote: > > Clang complains: > > > > In file included from synic.c:15: > > /builds/xen-project/xen/xen/include/asm/guest/hyperv-tlfs.h:900:18: error: field 'hv_vp_set' with variable sized type 'struct hv_vpset' not at the end of a struct or class is a GNU extension [-Werror,-Wgnu-variable-sized-type-not-at-end] > > struct hv_vpset hv_vp_set; > > ^ > > I'm surprised gcc does not complain. Me too. > > > 1 error generated. > > /builds/xen-project/xen/xen/Rules.mk:198: recipe for target 'synic.o' failed > > make[6]: *** [synic.o] Error 1 > > > > Drop the last variable size array from hv_tlb_flush_ex for now to fix > > clang builds. > > Why "for now"? The field is illegal there, and I can't see a way to > make it legal. To know its actual place in memory you need to know > the number of elements in bank_contents[], i.e. having the field > if the compiler erroneously accepted it would mean wrong code to > get generated (silently). > OK. I can drop "for now". > > --- a/xen/include/asm-x86/guest/hyperv-tlfs.h > > +++ b/xen/include/asm-x86/guest/hyperv-tlfs.h > > @@ -893,12 +893,11 @@ struct hv_tlb_flush { > > u64 gva_list[]; > > } __packed; > > > > -/* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */ > > +/* HvFlushVirtualAddressSpaceEx hypercall */ > > struct hv_tlb_flush_ex { > > u64 address_space; > > u64 flags; > > struct hv_vpset hv_vp_set; > > - u64 gva_list[]; > > Rather than outright removing the line, keep it as a comment? That's fine by me. Wei. > > Jan
diff --git a/xen/include/asm-x86/guest/hyperv-tlfs.h b/xen/include/asm-x86/guest/hyperv-tlfs.h index ccd9850b27..98ff1adc61 100644 --- a/xen/include/asm-x86/guest/hyperv-tlfs.h +++ b/xen/include/asm-x86/guest/hyperv-tlfs.h @@ -893,12 +893,11 @@ struct hv_tlb_flush { u64 gva_list[]; } __packed; -/* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */ +/* HvFlushVirtualAddressSpaceEx hypercall */ struct hv_tlb_flush_ex { u64 address_space; u64 flags; struct hv_vpset hv_vp_set; - u64 gva_list[]; } __packed; struct hv_partition_assist_pg {
Clang complains: In file included from synic.c:15: /builds/xen-project/xen/xen/include/asm/guest/hyperv-tlfs.h:900:18: error: field 'hv_vp_set' with variable sized type 'struct hv_vpset' not at the end of a struct or class is a GNU extension [-Werror,-Wgnu-variable-sized-type-not-at-end] struct hv_vpset hv_vp_set; ^ 1 error generated. /builds/xen-project/xen/xen/Rules.mk:198: recipe for target 'synic.o' failed make[6]: *** [synic.o] Error 1 Drop the last variable size array from hv_tlb_flush_ex for now to fix clang builds. Signed-off-by: Wei Liu <liuwe@microsoft.com> --- xen/include/asm-x86/guest/hyperv-tlfs.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)