On Wed, Aug 17, 2022, Uros Bizjak wrote: > There is no need to declare vmread_error asmlinkage, its arguments > can be passed via registers for both, 32-bit and 64-bit targets. > Function argument registers are considered call-clobbered registers, > they are saved in the trampoline just before the function call and > restored afterwards. > > Note that asmlinkage and __attribute__((regparm(0))) have no effect > on 64-bit targets. The trampoline is called from the assembler glue > code that implements its own stack-passing function calling convention, > so the attribute on the trampoline declaration does not change anything > for 64-bit as well as 32-bit targets. We can declare it asmlinkage for > documentation purposes. > > The patch unifies trampoline function argument handling between 32-bit > and 64-bit targets and improves generated code for 32-bit targets. > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Sean Christopherson <seanjc@xxxxxxxxxx> > Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx> > --- Minus the vmread_error_trampoline() change, pushed to branch `for_paolo/6.1` at: https://github.com/sean-jc/linux.git Unless you hear otherwise, it will make its way to kvm/queue "soon". Note, the commit IDs are not guaranteed to be stable.