Messages in this thread Patch in this message | | | Date | Wed, 23 Jul 2008 14:21:18 -0700 | From | Jeremy Fitzhardinge <> | Subject | [PATCH] x86/paravirt/xen: properly fill out the ldt ops |
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LTP testing showed that Xen does not properly implement sys_modify_ldt(). This patch does the final little bits needed to make the ldt work properly.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/kernel/ldt.c | 9 ++++++++- arch/x86/kernel/paravirt.c | 4 ++++ arch/x86/xen/enlighten.c | 23 +++++++++++++++++++++++ include/asm-x86/desc.h | 10 +++++++++- include/asm-x86/paravirt.h | 13 +++++++++++++ 5 files changed, 57 insertions(+), 2 deletions(-)
=================================================================== --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -52,6 +52,8 @@ memset(newldt + oldsize * LDT_ENTRY_SIZE, 0, (mincount - oldsize) * LDT_ENTRY_SIZE); + paravirt_alloc_ldt(newldt, mincount); + #ifdef CONFIG_X86_64 /* CHECKME: Do we really need this ? */ wmb(); @@ -76,6 +78,7 @@ #endif } if (oldsize) { + paravirt_free_ldt(oldldt, oldsize); if (oldsize * LDT_ENTRY_SIZE > PAGE_SIZE) vfree(oldldt); else @@ -87,10 +90,13 @@ static inline int copy_ldt(mm_context_t *new, mm_context_t *old) { int err = alloc_ldt(new, old->size, 0); + int i; if (err < 0) return err; - memcpy(new->ldt, old->ldt, old->size * LDT_ENTRY_SIZE); + + for(i = 0; i < old->size; i++) + write_ldt_entry(new->ldt, i, old->ldt + i * LDT_ENTRY_SIZE); return 0; } @@ -127,6 +133,7 @@ if (mm == current->active_mm) clear_LDT(); #endif + paravirt_free_ldt(mm->context.ldt, mm->context.size); if (mm->context.size * LDT_ENTRY_SIZE > PAGE_SIZE) vfree(mm->context.ldt); else =================================================================== --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -350,6 +350,10 @@ .write_ldt_entry = native_write_ldt_entry, .write_gdt_entry = native_write_gdt_entry, .write_idt_entry = native_write_idt_entry, + + .alloc_ldt = paravirt_nop, + .free_ldt = paravirt_nop, + .load_sp0 = native_load_sp0, #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) =================================================================== --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -327,6 +327,26 @@ static unsigned long xen_store_tr(void) { return 0; +} + +static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) +{ + unsigned pages = roundup(entries * LDT_ENTRY_SIZE, PAGE_SIZE); + void *v = ldt; + int i; + + for(i = 0; i < pages; i += PAGE_SIZE) + make_lowmem_page_readonly(v + i); +} + +static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) +{ + unsigned pages = roundup(entries * LDT_ENTRY_SIZE, PAGE_SIZE); + void *v = ldt; + int i; + + for(i = 0; i < pages; i += PAGE_SIZE) + make_lowmem_page_readwrite(v + i); } static void xen_set_ldt(const void *addr, unsigned entries) @@ -1269,6 +1289,9 @@ .load_gs_index = xen_load_gs_index, #endif + .alloc_ldt = xen_alloc_ldt, + .free_ldt = xen_free_ldt, + .store_gdt = native_store_gdt, .store_idt = native_store_idt, .store_tr = xen_store_tr, =================================================================== --- a/include/asm-x86/desc.h +++ b/include/asm-x86/desc.h @@ -97,7 +97,15 @@ native_write_gdt_entry(dt, entry, desc, type) #define write_idt_entry(dt, entry, g) \ native_write_idt_entry(dt, entry, g) -#endif + +static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries) +{ +} + +static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries) +{ +} +#endif /* CONFIG_PARAVIRT */ static inline void native_write_idt_entry(gate_desc *idt, int entry, const gate_desc *gate) =================================================================== --- a/include/asm-x86/paravirt.h +++ b/include/asm-x86/paravirt.h @@ -124,6 +124,9 @@ int entrynum, const void *desc, int size); void (*write_idt_entry)(gate_desc *, int entrynum, const gate_desc *gate); + void (*alloc_ldt)(struct desc_struct *ldt, unsigned entries); + void (*free_ldt)(struct desc_struct *ldt, unsigned entries); + void (*load_sp0)(struct tss_struct *tss, struct thread_struct *t); void (*set_iopl_mask)(unsigned mask); @@ -819,6 +822,16 @@ (aux) = __aux; \ } while (0) +static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries) +{ + PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries); +} + +static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries) +{ + PVOP_VCALL2(pv_cpu_ops.free_ldt, ldt, entries); +} + static inline void load_TR_desc(void) { PVOP_VCALL0(pv_cpu_ops.load_tr_desc);
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