diff options
| author | Tom Lendacky <thomas.lendacky@amd.com> | 2017-07-28 11:01:16 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-07-30 12:09:12 +0200 |
| commit | 4e237903f95db585b976e7311de2bfdaaf0f6e31 (patch) | |
| tree | d91a782eb24dc6409406be5ed50a736543aaf9f2 /arch/x86/kernel/relocate_kernel_64.S | |
| parent | f90e2d9a5235bdcfcf1979f5e4b40684e778d18b (diff) | |
x86/mm, kexec: Fix memory corruption with SME on successive kexecs
After issuing successive kexecs it was found that the SHA hash failed
verification when booting the kexec'd kernel. When SME is enabled, the
change from using pages that were marked encrypted to now being marked as
not encrypted (through new identify mapped page tables) results in memory
corruption if there are any cache entries for the previously encrypted
pages. This is because separate cache entries can exist for the same
physical location but tagged both with and without the encryption bit.
To prevent this, issue a wbinvd if SME is active before copying the pages
from the source location to the destination location to clear any possible
cache entry conflicts.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <kexec@lists.infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e7fb8610af3a93e8f8ae6f214cd9249adc0df2b4.1501186516.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/relocate_kernel_64.S')
| -rw-r--r-- | arch/x86/kernel/relocate_kernel_64.S | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 98111b38ebfd..307d3bac5f04 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -47,6 +47,7 @@ relocate_kernel: * %rsi page_list * %rdx start address * %rcx preserve_context + * %r8 sme_active */ /* Save the CPU context, used for jumping back */ @@ -71,6 +72,9 @@ relocate_kernel: pushq $0 popfq + /* Save SME active flag */ + movq %r8, %r12 + /* * get physical address of control page now * this is impossible after page table switch @@ -132,6 +136,16 @@ identity_mapped: /* Flush the TLB (needed?) */ movq %r9, %cr3 + /* + * If SME is active, there could be old encrypted cache line + * entries that will conflict with the now unencrypted memory + * used by kexec. Flush the caches before copying the kernel. + */ + testq %r12, %r12 + jz 1f + wbinvd +1: + movq %rcx, %r11 call swap_pages |