[PATCH 16 of 36] x86/paravirt: add a pgd_alloc/free hooks

Jeremy Fitzhardinge
2008-06-25T04:37:51Z

Add hooks which are called at pgd_alloc/free time. The pgd_alloc hook
may return an error code, which if non-zero, causes the pgd allocation
to be failed. The hooks may be used to allocate/free auxillary
per-pgd information.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
arch/x86/kernel/paravirt.c | 4 ++++
arch/x86/mm/pgtable.c | 13 ++++++++-----
arch/x86/xen/enlighten.c | 4 ++++
include/asm-x86/paravirt.h | 19 ++++++++++++++++++-
include/asm-x86/pgalloc.h | 4 ++++
5 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -30,6 +30,7 @@
#include <asm/setup.h>
#include <asm/arch_hooks.h>
#include <asm/time.h>
+#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/fixmap.h>
@@ -369,6 +370,9 @@
.flush_tlb_single = native_flush_tlb_single,
.flush_tlb_others = native_flush_tlb_others,

+ .pgd_alloc = __paravirt_pgd_alloc,
+ .pgd_free = paravirt_nop,
+
.alloc_pte = paravirt_nop,
.alloc_pmd = paravirt_nop,
.alloc_pmd_clone = paravirt_nop,
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -215,13 +215,15 @@

/* so that alloc_pmd can use it */
mm->pgd = pgd;
- if (pgd)
+ if (pgd) {
pgd_ctor(pgd);

- if (pgd && !pgd_prepopulate_pmd(mm, pgd)) {
- pgd_dtor(pgd);
- free_page((unsigned long)pgd);
- pgd = NULL;
+ if (paravirt_pgd_alloc(mm) != 0 ||
+ !pgd_prepopulate_pmd(mm, pgd)) {
+ pgd_dtor(pgd);
+ free_page((unsigned long)pgd);
+ pgd = NULL;
+ }
}

return pgd;
@@ -231,6 +233,7 @@
{
pgd_mop_up_pmds(mm, pgd);
pgd_dtor(pgd);
+ paravirt_pgd_free(mm, pgd);
free_page((unsigned long)pgd);
}

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -45,6 +45,7 @@
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/reboot.h>
+#include <asm/pgalloc.h>

#include "xen-ops.h"
#include "mmu.h"
@@ -1151,6 +1152,9 @@
.pte_update = paravirt_nop,
.pte_update_defer = paravirt_nop,

+ .pgd_alloc = __paravirt_pgd_alloc,
+ .pgd_free = paravirt_nop,
+
.alloc_pte = xen_alloc_pte_init,
.release_pte = xen_release_pte_init,
.alloc_pmd = xen_alloc_pte_init,
diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -220,7 +220,14 @@
void (*flush_tlb_others)(const cpumask_t *cpus, struct mm_struct *mm,
unsigned long va);

- /* Hooks for allocating/releasing pagetable pages */
+ /* Hooks for allocating and freeing a pagetable top-level */
+ int (*pgd_alloc)(struct mm_struct *mm);
+ void (*pgd_free)(struct mm_struct *mm, pgd_t *pgd);
+
+ /*
+ * Hooks for allocating/releasing pagetable pages when they're
+ * attached to a pagetable
+ */
void (*alloc_pte)(struct mm_struct *mm, u32 pfn);
void (*alloc_pmd)(struct mm_struct *mm, u32 pfn);
void (*alloc_pmd_clone)(u32 pfn, u32 clonepfn, u32 start, u32 count);
@@ -926,6 +933,16 @@
PVOP_VCALL3(pv_mmu_ops.flush_tlb_others, &cpumask, mm, va);
}

+static inline int paravirt_pgd_alloc(struct mm_struct *mm)
+{
+ return PVOP_CALL1(int, pv_mmu_ops.pgd_alloc, mm);
+}
+
+static inline void paravirt_pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+ PVOP_VCALL2(pv_mmu_ops.pgd_free, mm, pgd);
+}
+
static inline void paravirt_alloc_pte(struct mm_struct *mm, unsigned pfn)
{
PVOP_VCALL2(pv_mmu_ops.alloc_pte, mm, pfn);
diff --git a/include/asm-x86/pgalloc.h b/include/asm-x86/pgalloc.h
--- a/include/asm-x86/pgalloc.h
+++ b/include/asm-x86/pgalloc.h
@@ -5,9 +5,13 @@
#include <linux/mm.h> /* for struct page */
#include <linux/pagemap.h>

+static inline int __paravirt_pgd_alloc(struct mm_struct *mm) { return 0; }
+
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
+#define paravirt_pgd_alloc(mm) __paravirt_pgd_alloc(mm)
+static inline void paravirt_pgd_free(struct mm_struct *mm, pgd_t *) {}
static inline void paravirt_alloc_pte(struct mm_struct *mm, unsigned long pfn) {}
static inline void paravirt_alloc_pmd(struct mm_struct *mm, unsigned long pfn) {}
static inline void paravirt_alloc_pmd_clone(unsigned long pfn, unsigned long clonepfn,