On 12/21/23 at 11:36am, Sourabh Jain wrote: ...... > > > > diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h > > > > index 3d5b3d757bed..df6a6505e267 100644 > > > > --- a/include/uapi/linux/kexec.h > > > > +++ b/include/uapi/linux/kexec.h > > > > @@ -13,7 +13,7 @@ > > > > #define KEXEC_ON_CRASH 0x00000001 > > > > #define KEXEC_PRESERVE_CONTEXT 0x00000002 > > > > -#define KEXEC_UPDATE_FDT 0x00000008 > > > > +#define KEXEC_CRASH_HOTPLUG_UPDATE 0x00000004 > > > > #define KEXEC_UPDATE_ELFCOREHDR 0x00000004 > > > > #define KEXEC_ARCH_MASK 0xffff0000 > > > > /* > > > > > > > > With my understanding, the kexec flag should be indicating the action, > > > > the mem/cpu hotplug, but not relating to any detail. Imagine later > > > > another segment need be skipped on one ARCH again, then another flag > > > > need be added, this sounds not reasonable. > > > I strongly agree with you. The KEXEC_CRASH_HOTPLUG_UPDATE kexec flag > > > should be sufficient to inform the kernel that the kexec tool has been > > > updated > > > to support CPU/Memory hotplug for the kexec_load system call. Unfortunately, > > > we cannot use the 0x00000004 kexec flags bit for KEXEC_CRASH_HOTPLUG_UPDATE > > > at the moment. > > I am fine with 0x00000008 and a new flag, it has the same effect as > > #define KEXEC_CRASH_HOTPLUG_UPDATE 0x00000004 > > > > I am worried about the header file incompatiblity. > > If we are OK to have KEXEC_CRASH_HOTPLUG_UPDATE 0x00000008 as new bit > to introduce CPU/Memory hotplug feature for kexec_load syscall, we will not > have > compatibility issue. > > Let me write next version for this patch with KEXEC_CRASH_HOTPLUG_UPDATE > 0x00000008 > as new flag bit and show how it will be handled. I will also share kexec > code for clarity. It's great we are in the same page about segments excluding done in arch function. While It's a little unclear to me why we can't reuse 0x00000004 flag value. Then KEXEC_UPDATE_ELFCOREHDR will only exist in v6.6 kernel, and that bit won't be used in v6.7 and future version. Except of the existence in kexec-tools utility for XEN, do you see other barrier? I would like to know so that one day I can explain KEXEC_UPDATE_ELFCOREHDR to someone else if asked. _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
