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x86/mm: Prepare sme_encrypt_kernel() for PAGE aligned encryption

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In preparation for encrypting more than just the kernel, the encryption
support in sme_encrypt_kernel() needs to support 4KB page aligned
encryption instead of just 2MB large page aligned encryption.

Update the routines that populate the PGD to support non-2MB aligned
addresses.  This is done by creating PTE page tables for the start
and end portion of the address range that fall outside of the 2MB
alignment.  This results in, at most, two extra pages to hold the
PTE entries for each mapping of a range.

Tested-by: Gabriel Craciunescu <nix.or.die@gmail.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.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/20180110192626.6026.75387.stgit@tlendack-t1.amdoffice.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Tom Lendacky 2018-01-10 13:26:26 -06:00 • committed by Ingo Molnar
parent 2b5d00b6c2
commit cc5f01e28d
2 changed files with 121 additions and 22 deletions
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20
arch/x86/mm/mem_encrypt_boot.S
View file

@ -104,6 +104,7 @@ ENTRY(__enc_copy)
mov %rdx, %cr4
push %r15
push %r12
movq %rcx, %r9 /* Save kernel length */
movq %rdi, %r10 /* Save encrypted kernel address */
@ -119,21 +120,27 @@ ENTRY(__enc_copy)
wbinvd /* Invalidate any cache entries */
/* Copy/encrypt 2MB at a time */
/* Copy/encrypt up to 2MB at a time */
movq $PMD_PAGE_SIZE, %r12
1:
cmpq %r12, %r9
jnb 2f
movq %r9, %r12
2:
movq %r11, %rsi /* Source - decrypted kernel */
movq %r8, %rdi /* Dest - intermediate copy buffer */
movq $PMD_PAGE_SIZE, %rcx /* 2MB length */
movq %r12, %rcx
rep movsb
movq %r8, %rsi /* Source - intermediate copy buffer */
movq %r10, %rdi /* Dest - encrypted kernel */
movq $PMD_PAGE_SIZE, %rcx /* 2MB length */
movq %r12, %rcx
rep movsb
addq $PMD_PAGE_SIZE, %r11
addq $PMD_PAGE_SIZE, %r10
subq $PMD_PAGE_SIZE, %r9 /* Kernel length decrement */
addq %r12, %r11
addq %r12, %r10
subq %r12, %r9 /* Kernel length decrement */
jnz 1b /* Kernel length not zero? */
/* Restore PAT register */
@ -142,6 +149,7 @@ ENTRY(__enc_copy)
mov %r15, %rdx /* Restore original PAT value */
wrmsr
pop %r12
pop %r15
ret