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authorRusty Russell <rusty@rustcorp.com.au>2010-09-21 12:54:01 -0400
committerRusty Russell <rusty@rustcorp.com.au>2010-09-20 21:24:02 -0400
commit9b6efcd2e2275e13403700913b7a1da92cf11ad2 (patch)
tree894993458a343675e88111d0603ee8e2c8dc4ced
parent65745422a898741ee0e7068ef06624ab06e8aefa (diff)
lguest: update comments to reflect LHCALL_LOAD_GDT_ENTRY.
We used to have a hypercall which reloaded the entire GDT, then we switched to one which loaded a single entry (to match the IDT code). Some comments were not updated, so fix them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Reported by: Eviatar Khen <eviatarkhen@gmail.com>
-rw-r--r--arch/x86/lguest/boot.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 9257510b4836..9d5f55848455 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -324,9 +324,8 @@ static void lguest_load_gdt(const struct desc_ptr *desc)
324} 324}
325 325
326/* 326/*
327 * For a single GDT entry which changes, we do the lazy thing: alter our GDT, 327 * For a single GDT entry which changes, we simply change our copy and
328 * then tell the Host to reload the entire thing. This operation is so rare 328 * then tell the host about it.
329 * that this naive implementation is reasonable.
330 */ 329 */
331static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum, 330static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
332 const void *desc, int type) 331 const void *desc, int type)
@@ -338,9 +337,13 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
338} 337}
339 338
340/* 339/*
341 * OK, I lied. There are three "thread local storage" GDT entries which change 340 * There are three "thread local storage" GDT entries which change
342 * on every context switch (these three entries are how glibc implements 341 * on every context switch (these three entries are how glibc implements
343 * __thread variables). So we have a hypercall specifically for this case. 342 * __thread variables). As an optimization, we have a hypercall
343 * specifically for this case.
344 *
345 * Wouldn't it be nicer to have a general LOAD_GDT_ENTRIES hypercall
346 * which took a range of entries?
344 */ 347 */
345static void lguest_load_tls(struct thread_struct *t, unsigned int cpu) 348static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
346{ 349{