[Xen-devel] [patch 09/21] Xen-paravirt: Allow paravirt backend to select PGD allocation alignment

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

Xen requires pgds to be page-aligned, so make this a parameter which
can be set in the paravirt_ops structure.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>

--
 arch/i386/kernel/paravirt.c |    1 +
 arch/i386/mm/init.c         |    2 +-
 include/asm-i386/paravirt.h |    5 ++++-
 include/asm-i386/pgtable.h  |    6 ++++++
 4 files changed, 12 insertions(+), 2 deletions(-)

===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -573,6 +573,7 @@ struct paravirt_ops paravirt_ops = {
        .paravirt_enabled = 0,
        .kernel_rpl = 0,
        .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
+       .pgd_alignment = sizeof(pgd_t) * PTRS_PER_PGD,
 
        .patch = native_patch,
        .banner = default_banner,
===================================================================
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -745,7 +745,7 @@ void __init pgtable_cache_init(void)
        }
        pgd_cache = kmem_cache_create("pgd",
                                      PTRS_PER_PGD*sizeof(pgd_t),
-                                     PTRS_PER_PGD*sizeof(pgd_t),
+                                     PGD_ALIGNMENT,
                                      0, NULL, NULL);
        if (!pgd_cache)
                panic("pgtable_cache_init(): Cannot create pgd cache");
===================================================================
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -33,9 +33,12 @@ struct mm_struct;
 struct mm_struct;
 struct paravirt_ops
 {
+       int paravirt_enabled;
        unsigned int kernel_rpl;
+
        int shared_kernel_pmd;
-       int paravirt_enabled;
+       int pgd_alignment;
+
        const char *name;
 
        /*
===================================================================
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -270,6 +270,12 @@ static inline void vmalloc_sync_all(void
 #define pte_update_defer(mm, addr, ptep)       do { } while (0)
 #endif
 
+#ifdef CONFIG_PARAVIRT
+#define PGD_ALIGNMENT  (paravirt_ops.pgd_alignment)
+#else
+#define PGD_ALIGNMENT  (sizeof(pgd_t) * PTRS_PER_PGD)
+#endif
+
 /*
  * We only update the dirty/accessed state if we set
  * the dirty bit by hand in the kernel, since the hardware

-- 


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