On 01/01/14 04:35, Konrad Rzeszutek Wilk wrote: > From: Mukesh Rathor <mukesh.rat...@oracle.com> > > The VCPU bringup protocol follows the PV with certain twists. > From xen/include/public/arch-x86/xen.h: > > Also note that when calling DOMCTL_setvcpucontext and VCPU_initialise > for HVM and PVH guests, not all information in this structure is updated: > > - For HVM guests, the structures read include: fpu_ctxt (if > VGCT_I387_VALID is set), flags, user_regs, debugreg[*] > > - PVH guests are the same as HVM guests, but additionally use ctrlreg[3] to > set cr3. All other fields not used should be set to 0. > > This is what we do. We piggyback on the 'xen_setup_gdt' - but modify > a bit - we need to call 'load_percpu_segment' so that 'switch_to_new_gdt' > can load per-cpu data-structures. It has no effect on the VCPU0. > > We also piggyback on the %rdi register to pass in the CPU number - so > that when we bootup a new CPU, the cpu_bringup_and_idle will have > passed as the first parameter the CPU number (via %rdi for 64-bit). [...] > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -1413,14 +1413,19 @@ static void __init xen_boot_params_init_edd(void) > * Set up the GDT and segment registers for -fstack-protector. Until > * we do this, we have to be careful not to call any stack-protected > * function, which is most of the kernel. > + * > + * Note, that it is refok - b/c the only caller of this after init
Please spell out 'because' in full. b/c is too hard to read. Also list the callers (cpu_bringup_and_idle() I guess). > + * is PVH which is not going to use xen_load_gdt_boot or other > + * __init functions. > */ > -static void __init xen_setup_gdt(void) > +void __init_refok xen_setup_gdt(int cpu) __ref seems to be the correct section marker for this. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
