Re: [Qemu-devel] [PATCH qemu RFC 1/4] spapr: Allow changing kernel loading address

[Alexey Kardashevskiy]

On 23/07/2019 13:49, David Gibson wrote:
> On Sat, Jul 20, 2019 at 11:28:47AM +1000, Alexey Kardashevskiy wrote:
> > Useful for the debugging purposes.
>
> Am I correct in understanding this isn't actually necessary for the
> rest of the series to work, just useful for debugging?


Correct. When I just started and used stepping in gdb stub, it helped to 
have the kernel at specific location. And since there is another 
property added in this patchset - "bios" - I did not really want to 
rebase (I will have to anyway if we decide to proceed). Thanks,


> > Signed-off-by: Alexey Kardashevskiy <address@hidden>
> > ---
> >   include/hw/ppc/spapr.h |  1 +
> >   hw/ppc/spapr.c         | 33 +++++++++++++++++++++++++++------
> >   2 files changed, 28 insertions(+), 6 deletions(-)
> >
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 74e427b588fc..ff82bb8554e1 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -159,6 +159,7 @@ struct SpaprMachineState {
> >       void *fdt_blob;
> >       long kernel_size;
> >       bool kernel_le;
> > +    uint64_t kernel_addr;
> >       uint32_t initrd_base;
> >       long initrd_size;
> >       uint64_t rtc_offset; /* Now used only during incoming migration */
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 7fad42350538..6d13d65d8996 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1179,7 +1179,7 @@ static void spapr_dt_chosen(SpaprMachineState *spapr, 
> > void *fdt)
> >                             spapr->initrd_base + spapr->initrd_size));
> >   
> >       if (spapr->kernel_size) {
> > -        uint64_t kprop[2] = { cpu_to_be64(KERNEL_LOAD_ADDR),
> > +        uint64_t kprop[2] = { cpu_to_be64(spapr->kernel_addr),
> >                                 cpu_to_be64(spapr->kernel_size) };
> >   
> >           _FDT(fdt_setprop(fdt, chosen, "qemu,boot-kernel",
> > @@ -1365,7 +1365,7 @@ static void *spapr_build_fdt(SpaprMachineState *spapr)
> >   
> >       /* Build memory reserve map */
> >       if (spapr->kernel_size) {
> > -        _FDT((fdt_add_mem_rsv(fdt, KERNEL_LOAD_ADDR, spapr->kernel_size)));
> > +        _FDT((fdt_add_mem_rsv(fdt, spapr->kernel_addr, spapr->kernel_size)));
> >       }
> >       if (spapr->initrd_size) {
> >           _FDT((fdt_add_mem_rsv(fdt, spapr->initrd_base, spapr->initrd_size)));
> > @@ -1391,7 +1391,8 @@ static void *spapr_build_fdt(SpaprMachineState *spapr)
> >   
> >   static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
> >   {
> > -    return (addr & 0x0fffffff) + KERNEL_LOAD_ADDR;
> > +    SpaprMachineState *spapr = opaque;
> > +    return (addr & 0x0fffffff) + spapr->kernel_addr;
> >   }
> >   
> >   static void emulate_spapr_hypercall(PPCVirtualHypervisor *vhyp,
> > @@ -2995,12 +2996,12 @@ static void spapr_machine_init(MachineState *machine)
> >           uint64_t lowaddr = 0;
> >   
> >           spapr->kernel_size = load_elf(kernel_filename, NULL,
> > -                                      translate_kernel_address, NULL,
> > +                                      translate_kernel_address, spapr,
> >                                         NULL, &lowaddr, NULL, 1,
> >                                         PPC_ELF_MACHINE, 0, 0);
> >           if (spapr->kernel_size == ELF_LOAD_WRONG_ENDIAN) {
> >               spapr->kernel_size = load_elf(kernel_filename, NULL,
> > -                                          translate_kernel_address, NULL, NULL,
> > +                                          translate_kernel_address, spapr, 
> > NULL,
> >                                             &lowaddr, NULL, 0, PPC_ELF_MACHINE,
> >                                             0, 0);
> >               spapr->kernel_le = spapr->kernel_size > 0;
> > @@ -3016,7 +3017,7 @@ static void spapr_machine_init(MachineState *machine)
> >               /* Try to locate the initrd in the gap between the kernel
> >                * and the firmware. Add a bit of space just in case
> >                */
> > -            spapr->initrd_base = (KERNEL_LOAD_ADDR + spapr->kernel_size
> > +            spapr->initrd_base = (spapr->kernel_addr + spapr->kernel_size
> >                                     + 0x1ffff) & ~0xffff;
> >               spapr->initrd_size = load_image_targphys(initrd_filename,
> >                                                        spapr->initrd_base,
> > @@ -3253,6 +3254,18 @@ static void spapr_set_vsmt(Object *obj, Visitor *v, 
> > const char *name,
> >       visit_type_uint32(v, name, (uint32_t *)opaque, errp);
> >   }
> >   
> > +static void spapr_get_kernel_addr(Object *obj, Visitor *v, const char *name,
> > +                                  void *opaque, Error **errp)
> > +{
> > +    visit_type_uint64(v, name, (uint64_t *)opaque, errp);
> > +}
> > +
> > +static void spapr_set_kernel_addr(Object *obj, Visitor *v, const char *name,
> > +                                  void *opaque, Error **errp)
> > +{
> > +    visit_type_uint64(v, name, (uint64_t *)opaque, errp);
> > +}
> > +
> >   static char *spapr_get_ic_mode(Object *obj, Error **errp)
> >   {
> >       SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> > @@ -3358,6 +3371,14 @@ static void spapr_instance_init(Object *obj)
> >       object_property_add_bool(obj, "vfio-no-msix-emulation",
> >                                spapr_get_msix_emulation, NULL, NULL);
> >   
> > +    object_property_add(obj, "kernel-addr", "uint64", spapr_get_kernel_addr,
> > +                        spapr_set_kernel_addr, NULL, &spapr->kernel_addr,
> > +                        &error_abort);
> > +    object_property_set_description(obj, "kernel-addr",
> > +                                    stringify(KERNEL_LOAD_ADDR)
> > +                                    " for -kernel is the default",
> > +                                    NULL);
> > +    spapr->kernel_addr = KERNEL_LOAD_ADDR;
> >       /* The machine class defines the default interrupt controller mode */
> >       spapr->irq = smc->irq;
> >       object_property_add_str(obj, "ic-mode", spapr_get_ic_mode,

--
Alexey