bdec8d7fa5
Commit
1958b5fc4010 ("x86/boot: Add early boot support when running with SEV active")
can occasionally cause system resets when kexec-ing a second kernel even
if SEV is not active.
That's because get_sev_encryption_bit() uses 32-bit rIP-relative
addressing to read the value of enc_bit - a variable which caches a
previously detected encryption bit position - but kexec may allocate
the early boot code to a higher location, beyond the 32-bit addressing
limit.
In this case, garbage will be read and get_sev_encryption_bit() will
return the wrong value, leading to accessing memory with the wrong
encryption setting.
Therefore, remove enc_bit, and thus get rid of the need to do 32-bit
rIP-relative addressing in the first place.
[ bp: massage commit message heavily. ]
Fixes: 1958b5fc4010 ("x86/boot: Add early boot support when running with SEV active")
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Kairui Song <kasong@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: brijesh.singh@amd.com
Cc: kexec@lists.infradead.org
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: ghook@redhat.com
Link: https://lkml.kernel.org/r/20180927123845.32052-1-kasong@redhat.com
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| .. | ||
| compressed | ||
| tools | ||
| .gitignore | ||
| a20.c | ||
| apm.c | ||
| bioscall.S | ||
| bitops.h | ||
| boot.h | ||
| cmdline.c | ||
| code16gcc.h | ||
| copy.S | ||
| cpu.c | ||
| cpucheck.c | ||
| cpuflags.c | ||
| cpuflags.h | ||
| ctype.h | ||
| early_serial_console.c | ||
| edd.c | ||
| genimage.sh | ||
| header.S | ||
| install.sh | ||
| main.c | ||
| Makefile | ||
| memory.c | ||
| mkcpustr.c | ||
| mtools.conf.in | ||
| pm.c | ||
| pmjump.S | ||
| printf.c | ||
| regs.c | ||
| setup.ld | ||
| string.c | ||
| string.h | ||
| tty.c | ||
| version.c | ||
| vesa.h | ||
| video-bios.c | ||
| video-mode.c | ||
| video-vesa.c | ||
| video-vga.c | ||
| video.c | ||
| video.h | ||