On 11/26/13 at 07:30pm, Matt Fleming wrote: > On Tue, 26 Nov, at 01:57:51PM, Dave Young wrote: > > kexec kernel will need exactly same mapping for > > efi runtime memory ranges. Thus here export the > > runtime ranges mapping to sysfs, kexec-tools > > will assemble them and pass to 2nd kernel via > > setup_data. > > > > Introducing a new directly /sys/firmware/efi/runtime-map > > I'm not sure why the word "directly" is used here? should be directory, will fix. > > > Just like /sys/firmware/memmap. Containing below attribute > > in each file of that directory: > > attribute num_pages phys_addr type virt_addr > > > > It will not work for efi 32bit. Only x86_64 currently. > > Actually, exporting the tables does work for 32-bit, right? It's just > that kexec doesn't work for 32-bit EFI? It does not make sense to export them for 32-bit because we do not support kexec efi on 32-bit. Will change the description to below: "kexec efi boot on 32-bit is not supported so I only export the tables for 64-bit efi system." > > > Matt: s/efi-runtime-map.c/runtime-map.c > > change dir name to runtime-map > > update to use desc_size in efi_runtime_map > > cleaup the code, add function efi_save_runtime_map > > improve err handling > > > > Signed-off-by: Dave Young <dyoung at redhat.com> > > --- > > .../ABI/testing/sysfs-firmware-efi-runtime-map | 45 +++++ > > arch/x86/platform/efi/efi.c | 26 +++ > > drivers/firmware/efi/Kconfig | 10 ++ > > drivers/firmware/efi/Makefile | 1 + > > drivers/firmware/efi/efi.c | 3 +- > > drivers/firmware/efi/runtime-map.c | 199 +++++++++++++++++++++ > > include/linux/efi.h | 6 + > > 7 files changed, 289 insertions(+), 1 deletion(-) > > create mode 100644 Documentation/ABI/testing/sysfs-firmware-efi-runtime-map > > create mode 100644 drivers/firmware/efi/runtime-map.c > > > > diff --git a/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map b/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map > > new file mode 100644 > > index 0000000..dab8d41 > > --- /dev/null > > +++ b/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map > > @@ -0,0 +1,45 @@ > > +What: /sys/firmware/efi/runtime-map/ > > +Date: Oct 2013 > > +Contact: Dave Young <dyoung at redhat.com> > > +Description: > > + Switching efi runtime services to virtual mode requires > > + that all efi memory ranges which has the runtime attribute > > + bit set to be mapped to virtual addresses. > > + > > + In kexec kernel kernel can not entering virtual mode again > > + because there's a limitation that SetVirtualAddressMap can > > + only be called once for entering virtual mode. But kexec > > + kernel still need maintain same physical address to virtual > > + address mapping as the 1st kernel. The mappings are exported > > + to sysfs so userspace tools can reassemble them and pass them > > + into kexec kernel. > > How about, > > "The efi runtime services can only be switched to virtual > mode once without rebooting. The kexec kernel must maintain > the same physical to virtual address mappings as the first > kernel. The mappings are exported to sysfs so userspace tools > can reassemble them and pass them into the kexec kernel." > > ? Excellent, will above. > > > + /sys/firmware/efi/runtim-map/ is what kernel export for > > ^^ runtime-map/ Will fix the typo. Thanks for review Dave
