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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>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge 2008-07-23 14:21:18 -07:00 committed by Ingo Molnar
parent 338b9bb3ad
commit 38ffbe66d5
5 changed files with 57 additions and 2 deletions
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9
arch/x86/kernel/ldt.c
View file

@ -51,6 +51,8 @@ static int alloc_ldt(mm_context_t *pc, int mincount, int reload)
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();
@ -75,6 +77,7 @@ static int alloc_ldt(mm_context_t *pc, int mincount, int reload)
#endif
}
if (oldsize) {
paravirt_free_ldt(oldldt, oldsize);
if (oldsize * LDT_ENTRY_SIZE > PAGE_SIZE)
vfree(oldldt);
else
@ -86,10 +89,13 @@ static int alloc_ldt(mm_context_t *pc, int mincount, int reload)
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;
}
@ -126,6 +132,7 @@ void destroy_context(struct mm_struct *mm)
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

4
arch/x86/kernel/paravirt.c
View file

@ -348,6 +348,10 @@ struct pv_cpu_ops pv_cpu_ops = {
.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)

23
arch/x86/xen/enlighten.c
View file

@ -325,6 +325,26 @@ 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)
{
struct mmuext_op *op;
@ -1220,6 +1240,9 @@ static const struct pv_cpu_ops xen_cpu_ops __initdata = {
.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,

10
include/asm-x86/desc.h
View file

@ -97,7 +97,15 @@ static inline int desc_empty(const void *ptr)
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)

13
include/asm-x86/paravirt.h
View file

@ -124,6 +124,9 @@ struct pv_cpu_ops {
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);
@ -824,6 +827,16 @@ do { \
(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);