Avi Kivity wrote: > Anthony Liguori wrote: > > >> - nr = vcpu->regs[VCPU_REGS_RBX] & -1u; >> - a0 = vcpu->regs[VCPU_REGS_RAX] & -1u; >> + nr = vcpu->regs[VCPU_REGS_RAX] & -1u; >> + a0 = vcpu->regs[VCPU_REGS_RBX] & -1u; > > >> - * Each hypercall may have 0-6 parameters. >> - * >> - * 64-bit hypercall index is in RAX, goes from 0 to __NR_hypercalls-1 >> - * >> - * 64-bit parameters 1-6 are in the standard gcc x86_64 calling >> convention >> - * order: RDI, RSI, RDX, RCX, R8, R9. >> + * Each hypercall may have 0-4 parameters. >> * >> - * 32-bit index is EBX, parameters are: EAX, ECX, EDX, ESI, EDI, EBP. >> - * (the first 3 are according to the gcc regparm calling convention) >> + * 32-bit index is EAX, parameters are: EBX, ECX, EDX, ESI. > > > What's the motivation for these changes?
If we're queuing hypercalls, then having 4 arguments verses 6 means that we can queue 50% more hypercalls in a single page. Using all six arguments clobbers all the GP registers in 32-bit mode too. Regards, Anthony Liguori > > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
