[Xen-devel] [PATCH 2 of 4] paravirt: add hooks for pte_rmw_start/commit

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

This patch adds paravirt-ops hooks in pv_mmu_ops for pte_rmw_start and
pte_rmw_commit.  This allows the hypervisor-specific backends to
implement these in some more efficient way.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
 arch/x86/kernel/paravirt.c |    3 +++
 arch/x86/xen/enlighten.c   |    3 +++
 include/asm-x86/paravirt.h |   26 ++++++++++++++++++++++++++
 3 files changed, 32 insertions(+)

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
@@ -383,6 +383,9 @@
        .pte_update = paravirt_nop,
        .pte_update_defer = paravirt_nop,
 
+       .pte_rmw_start = __pte_rmw_start,
+       .pte_rmw_commit = __pte_rmw_commit,
+
 #ifdef CONFIG_HIGHPTE
        .kmap_atomic_pte = kmap_atomic,
 #endif
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
@@ -1103,6 +1103,9 @@
        .set_pte_at = xen_set_pte_at,
        .set_pmd = xen_set_pmd,
 
+       .pte_rmw_start = __pte_rmw_start,
+       .pte_rmw_commit = __pte_rmw_commit,
+
        .pte_val = xen_pte_val,
        .pte_flags = native_pte_val,
        .pgd_val = xen_pgd_val,
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
@@ -238,6 +238,11 @@
                           pte_t *ptep);
        void (*pte_update_defer)(struct mm_struct *mm,
                                 unsigned long addr, pte_t *ptep);
+
+       pte_t (*pte_rmw_start)(struct mm_struct *mm, unsigned long addr,
+                              pte_t *ptep);
+       void (*pte_rmw_commit)(struct mm_struct *mm, unsigned long addr,
+                              pte_t *ptep, pte_t pte);
 
        pteval_t (*pte_val)(pte_t);
        pteval_t (*pte_flags)(pte_t);
@@ -1040,6 +1045,27 @@
        return ret;
 }
 
+#define  __HAVE_ARCH_PTE_RMW_TRANSACTION
+static inline pte_t pte_rmw_start(struct mm_struct *mm, unsigned long addr,
+                                 pte_t *ptep)
+{
+       pteval_t ret;
+
+       ret = PVOP_CALL3(pteval_t, pv_mmu_ops.pte_rmw_start, mm, addr, ptep);
+
+       return (pte_t) { .pte = ret };
+}
+
+static inline void pte_rmw_commit(struct mm_struct *mm, unsigned long addr,
+                                  pte_t *ptep, pte_t pte)
+{
+       if (sizeof(pteval_t) > sizeof(long))
+               /* 5 arg words */
+               pv_mmu_ops.pte_rmw_commit(mm, addr, ptep, pte);
+       else
+               PVOP_VCALL4(pv_mmu_ops.pte_rmw_commit, mm, addr, ptep, pte.pte);
+}
+
 static inline void set_pte(pte_t *ptep, pte_t pte)
 {
        if (sizeof(pteval_t) > sizeof(long))



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