x86/kexec: Do not reserve EFI setup_data in the kexec e820 table
The e820 table for the kexec kernel unconditionally marks setup_data as reserved because the second kernel can reuse setup_data passed by the 1st kernel's boot loader, for example SETUP_PCI marked regions like PCI BIOS, etc. SETUP_EFI types, however, are used by kexec itself to enable EFI in the 2nd kernel. Thus, it is pointless to add this type of setup_data to the kexec e820 table as reserved. IOW, what happens is this: - 1st physical boot: no SETUP_EFI. - kexec loads a new kernel and prepares a SETUP_EFI setup_data blob, then reboots the machine. - 2nd kernel sees SETUP_EFI, reserves it both in the e820 and in the kexec e820 table. - If another kexec load is executed, it prepares a new SETUP_EFI blob and then reboots the machine into the new kernel. 5. The 3rd kexec-ed kernel has two SETUP_EFI ranges reserved. And so on... Thus skip SETUP_EFI while reserving setup_data in the e820_table_kexec table because it is not needed. [ bp: Heavily massage commit message, shorten line and improve comment. ] Signed-off-by:Dave Young <dyoung@redhat.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200212110424.GA2938@dhcp-128-65.nay.redhat.com
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