On Tue, 20 Jan 2026 21:54:30 +0100 Ard Biesheuvel <[email protected]> wrote:
> On Tue, 20 Jan 2026 at 20:44, David Laight <[email protected]> > wrote: > > > > On Tue, 20 Jan 2026 09:04:26 -0800 > > Sean Christopherson <[email protected]> wrote: > > > > > 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. > > > > I remember taking a while to grok that as well. > > > > Can't you just use . as in: > > leaq .(%rip), %rax > > > > How would the other two instructions referring to '0b' in their > immediates refer to '.' in that case? I'd forgotten about those, not in the quoted bit of patch :-( Traditionally (going back to MACRO-11) numeric labels would start at 10 and go up in 10s, TECO had a nice macro to renumber them. (Showing my age again) David
