2024-03-24 04:06:19

by tip-bot2 for Tony Luck

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Subject: [tip: x86/urgent] x86/boot/64: Apply encryption mask to 5-level pagetable update

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 4d0d7e7852752ea56375ac8645f0239e21ca2b50
Gitweb: https://git.kernel.org/tip/4d0d7e7852752ea56375ac8645f0239e21ca2b50
Author: Tom Lendacky <[email protected]>
AuthorDate: Fri, 22 Mar 2024 10:41:06 -05:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Sun, 24 Mar 2024 05:00:35 +01:00

x86/boot/64: Apply encryption mask to 5-level pagetable update

When running with 5-level page tables, the kernel mapping PGD entry is
updated to point to the P4D table. The assignment uses _PAGE_TABLE_NOENC,
which, when SME is active (mem_encrypt=on), results in a page table
entry without the encryption mask set, causing the system to crash on
boot.

Change the assignment to use _PAGE_TABLE instead of _PAGE_TABLE_NOENC so
that the encryption mask is set for the PGD entry.

Fixes: 533568e06b15 ("x86/boot/64: Use RIP_REL_REF() to access early_top_pgt[]")
Signed-off-by: Tom Lendacky <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/8f20345cda7dbba2cf748b286e1bc00816fe649a.1711122067.git.thomas.lendacky@amd.com
---
arch/x86/kernel/head64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 212e8e0..7d2eb03 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -175,7 +175,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
p4d = (p4dval_t *)&RIP_REL_REF(level4_kernel_pgt);
p4d[MAX_PTRS_PER_P4D - 1] += load_delta;

- pgd[pgd_index(__START_KERNEL_map)] = (pgdval_t)p4d | _PAGE_TABLE_NOENC;
+ pgd[pgd_index(__START_KERNEL_map)] = (pgdval_t)p4d | _PAGE_TABLE;
}

RIP_REL_REF(level3_kernel_pgt)[PTRS_PER_PUD - 2].pud += load_delta;