On 25/01/18 12:00, Greg KH wrote: > On Thu, Jan 25, 2018 at 11:49:35AM +0100, Juergen Gross wrote: >> On 25/01/18 11:37, Greg KH wrote: >>> On Thu, Jan 25, 2018 at 11:04:54AM +0100, Juergen Gross wrote: >>>> Add acpi_arch_get_root_pointer() for Xen PVH guests to communicate >>>> the address of the RSDP table given to the kernel via Xen start info. >>>> >>>> This makes the kernel boot again in PVH mode after on recent Xen the >>>> RSDP was moved to higher addresses. So up to that change it was pure >>>> luck that the legacy method to locate the RSDP was working when >>>> running as PVH mode. >>>> >>>> Cc: <stable@xxxxxxxxxxxxxxx> # 4.11 >>>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx> >>>> --- >>>> arch/x86/xen/enlighten_pvh.c | 15 ++++++++++++--- >>>> 1 file changed, 12 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c >>>> index 436c4f003e17..9a5c3a7fe673 100644 >>>> --- a/arch/x86/xen/enlighten_pvh.c >>>> +++ b/arch/x86/xen/enlighten_pvh.c >>>> @@ -16,15 +16,24 @@ >>>> /* >>>> * PVH variables. >>>> * >>>> - * xen_pvh and pvh_bootparams need to live in data segment since they >>>> - * are used after startup_{32|64}, which clear .bss, are invoked. >>>> + * xen_pvh, pvh_bootparams and pvh_start_info need to live in data segment >>>> + * since they are used after startup_{32|64}, which clear .bss, are invoked. >>>> */ >>>> bool xen_pvh __attribute__((section(".data"))) = 0; >>>> struct boot_params pvh_bootparams __attribute__((section(".data"))); >>>> +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); >>>> >>>> -struct hvm_start_info pvh_start_info; >>>> unsigned int pvh_start_info_sz = sizeof(pvh_start_info); >>>> >>>> +acpi_physical_address acpi_arch_get_root_pointer(void) >>>> +{ >>>> + if (xen_pvh) >>>> + return pvh_start_info.rsdp_paddr; >>>> + >>>> + return 0; >>>> +} >>>> +EXPORT_SYMBOL_GPL(acpi_arch_get_root_pointer); >>> >>> Why does this have to be an exported symbol? Does this code get built >>> as a module and will the linker somehow go and rewrite the previous call >>> places with this one if it gets loaded? >> >> With being called by drivers/acpi/... I just wanted to make sure it is >> working properly even in case the acpi code is built as a module. > > I didn't think the core ACPI code can be built as a module, have you > tried that? No, but as the build wouldn't break whenever this is changed I wanted to make sure the symbol is found. If you feel strong about that I can remove the EXPORT_SYMBOL_GPL(). Juergen