On Thu, Jan 08, 2026, Ard Biesheuvel wrote: > Replace absolute references in inline asm with RIP-relative ones, to > avoid the need for relocation fixups at boot time. This is a > prerequisite for PIE linking, which only permits 64-bit wide > loader-visible absolute references. > > Signed-off-by: Ard Biesheuvel <[email protected]> > --- > arch/x86/kernel/kvm.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index df78ddee0abb..1a0335f328e1 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -807,8 +807,9 @@ extern bool > __raw_callee_save___kvm_vcpu_is_preempted(long); > * restoring to/from the stack. > */ > #define PV_VCPU_PREEMPTED_ASM > \ > - "movq __per_cpu_offset(,%rdi,8), %rax\n\t" > \ > - "cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax)\n\t" > \ > + "0:leaq 0b(%rip), %rax\n\t" \
Please use something other than '0' for the label, it took me forever (and looking at disassembly) to realize "0b" was just a backwards label and not some fancy syntax I didn't know. It might also be worth calling out in the changelog that this function is called across CPUs, e.g. from kvm_smp_send_call_func_ipi(), and thus can't use gs: or any other "normal" method for accessing per-CPU data. > + "addq __per_cpu_offset - 0b(%rax,%rdi,8), %rax\n\t" > \ > + "cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) > "+steal_time-0b(%rax)\n\t" \ > "setne %al\n\t" > > DEFINE_ASM_FUNC(__raw_callee_save___kvm_vcpu_is_preempted, > -- > 2.47.3 >
