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| author | Tom Lendacky <thomas.lendacky@amd.com> | 2021-10-15 19:24:16 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-19 14:07:17 +0200 |
| commit | e7d445ab26db833d6640d4c9a08bee176777cc82 (patch) | |
| tree | e32724a851b61bafed62ac90c06ac82c43d305d6 /arch/x86/mm/mem_encrypt_identity.c | |
| parent | x86/sev: Carve out HV call's return value verification (diff) | |
| download | linux-e7d445ab26db833d6640d4c9a08bee176777cc82.tar.xz linux-e7d445ab26db833d6640d4c9a08bee176777cc82.zip | |
x86/sme: Use #define USE_EARLY_PGTABLE_L5 in mem_encrypt_identity.c
When runtime support for converting between 4-level and 5-level pagetables
was added to the kernel, the SME code that built pagetables was updated
to use the pagetable functions, e.g. p4d_offset(), etc., in order to
simplify the code. However, the use of the pagetable functions in early
boot code requires the use of the USE_EARLY_PGTABLE_L5 #define in order to
ensure that the proper definition of pgtable_l5_enabled() is used.
Without the #define, pgtable_l5_enabled() is #defined as
cpu_feature_enabled(X86_FEATURE_LA57). In early boot, the CPU features
have not yet been discovered and populated, so pgtable_l5_enabled() will
return false even when 5-level paging is enabled. This causes the SME code
to always build 4-level pagetables to perform the in-place encryption.
If 5-level paging is enabled, switching to the SME pagetables results in
a page-fault that kills the boot.
Adding the #define results in pgtable_l5_enabled() using the
__pgtable_l5_enabled variable set in early boot and the SME code building
pagetables for the proper paging level.
Fixes: aad983913d77 ("x86/mm/encrypt: Simplify sme_populate_pgd() and sme_populate_pgd_large()")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> # 4.18.x
Link: https://lkml.kernel.org/r/2cb8329655f5c753905812d951e212022a480475.1634318656.git.thomas.lendacky@amd.com
Diffstat (limited to 'arch/x86/mm/mem_encrypt_identity.c')
| -rw-r--r-- | arch/x86/mm/mem_encrypt_identity.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index 470b20208430..700ce8fdea87 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -27,6 +27,15 @@ #undef CONFIG_PARAVIRT_XXL #undef CONFIG_PARAVIRT_SPINLOCKS +/* + * This code runs before CPU feature bits are set. By default, the + * pgtable_l5_enabled() function uses bit X86_FEATURE_LA57 to determine if + * 5-level paging is active, so that won't work here. USE_EARLY_PGTABLE_L5 + * is provided to handle this situation and, instead, use a variable that + * has been set by the early boot code. + */ +#define USE_EARLY_PGTABLE_L5 + #include <linux/kernel.h> #include <linux/mm.h> #include <linux/mem_encrypt.h> |