diff options
| author | Dave Hansen <dave.hansen@linux.intel.com> | 2025-04-14 10:32:40 -0700 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2025-04-17 10:39:25 -0700 |
| commit | 82f120010f3b86c2f9c1279452c1ecab7bc117d2 (patch) | |
| tree | dc979950f18b4df10bfc13a051108259bdc2f92b /arch/x86/mm/pgtable.c | |
| parent | 45fb940563f80b8138f465f18d71c2d3e4a0724e (diff) | |
x86/mm: Fix up comments around PMD preallocation
The "paravirt environment" is no longer in the tree. Axe that part of the
comment. Also add a blurb to remind readers that "USER_PMDS" refer to
the PTI user *copy* of the page tables, not the user *portion*.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20250414173240.5B1AB322%40davehans-spike.ostc.intel.com
Diffstat (limited to 'arch/x86/mm/pgtable.c')
| -rw-r--r-- | arch/x86/mm/pgtable.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 027e1d32925c..ca07db510d26 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -121,16 +121,17 @@ static void pgd_dtor(pgd_t *pgd) * processor notices the update. Since this is expensive, and * all 4 top-level entries are used almost immediately in a * new process's life, we just pre-populate them here. - * - * Also, if we're in a paravirt environment where the kernel pmd is - * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate - * and initialize the kernel pmds here. */ #define PREALLOCATED_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \ PTRS_PER_PGD : KERNEL_PGD_BOUNDARY) #define MAX_PREALLOCATED_PMDS PTRS_PER_PGD /* + * "USER_PMDS" are the PMDs for the user copy of the page tables when + * PTI is enabled. They do not exist when PTI is disabled. Note that + * this is distinct from the user _portion_ of the kernel page tables + * which always exists. + * * We allocate separate PMDs for the kernel part of the user page-table * when PTI is enabled. We need them to map the per-process LDT into the * user-space page-table. |