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authorRusty Russell <rusty@rustcorp.com.au>2010-09-21 10:54:01 -0600
committerRusty Russell <rusty@rustcorp.com.au>2010-09-21 10:54:02 +0930
commit9b6efcd2e2275e13403700913b7a1da92cf11ad2 (patch)
tree894993458a343675e88111d0603ee8e2c8dc4ced /arch/x86/lguest
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>
Diffstat (limited to 'arch/x86/lguest')
-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)
}
/*
- * For a single GDT entry which changes, we do the lazy thing: alter our GDT,
- * then tell the Host to reload the entire thing. This operation is so rare
- * that this naive implementation is reasonable.
+ * For a single GDT entry which changes, we simply change our copy and
+ * then tell the host about it.
*/
static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
const void *desc, int type)
@@ -338,9 +337,13 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
}
/*
- * OK, I lied. There are three "thread local storage" GDT entries which change
+ * There are three "thread local storage" GDT entries which change
* on every context switch (these three entries are how glibc implements
- * __thread variables). So we have a hypercall specifically for this case.
+ * __thread variables). As an optimization, we have a hypercall
+ * specifically for this case.
+ *
+ * Wouldn't it be nicer to have a general LOAD_GDT_ENTRIES hypercall
+ * which took a range of entries?
*/
static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
{

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