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372d070845
Change the mov in KVM_ASM_SAFE() that zeroes @vector to a movb to
make it unambiguous.
This fixes a build failure with Clang since, unlike the GNU assembler,
the LLVM integrated assembler rejects ambiguous X86 instructions that
don't have suffixes:
In file included from x86_64/hyperv_features.c:13:
include/x86_64/processor.h:825:9: error: ambiguous instructions require an explicit suffix (could be 'movb', 'movw', 'movl', or 'movq')
return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr));
^
include/x86_64/processor.h:802:15: note: expanded from macro 'kvm_asm_safe'
asm volatile(KVM_ASM_SAFE(insn) \
^
include/x86_64/processor.h:788:16: note: expanded from macro 'KVM_ASM_SAFE'
"1: " insn "\n\t" \
^
<inline asm>:5:2: note: instantiated into assembly here
mov $0, 15(%rsp)
^
It seems like this change could introduce undesirable behavior in the
future, e.g. if someone used a type larger than a u8 for @vector, since
KVM_ASM_SAFE() will only zero the bottom byte. I tried changing the type
of @vector to an int to see what would happen. GCC failed to compile due
to a size mismatch between `movb` and `%eax`. Clang succeeded in
compiling, but the generated code looked correct, so perhaps it will not
be an issue. That being said it seems like there could be a better
solution to this issue that does not assume @vector is a u8.
Fixes:
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|---|---|---|
| .. | ||
| aarch64 | ||
| include | ||
| lib | ||
| s390x | ||
| x86_64 | ||
| .gitignore | ||
| access_tracking_perf_test.c | ||
| config | ||
| demand_paging_test.c | ||
| dirty_log_perf_test.c | ||
| dirty_log_test.c | ||
| hardware_disable_test.c | ||
| kvm_binary_stats_test.c | ||
| kvm_create_max_vcpus.c | ||
| kvm_page_table_test.c | ||
| Makefile | ||
| max_guest_memory_test.c | ||
| memslot_modification_stress_test.c | ||
| memslot_perf_test.c | ||
| rseq_test.c | ||
| set_memory_region_test.c | ||
| settings | ||
| steal_time.c | ||
| system_counter_offset_test.c | ||