lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

lguest: update comments to reflect LHCALL_LOAD_GDT_ENTRY.

Browse Source 
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>
This commit is contained in:
Rusty Russell
2010-09-21 10:54:01 -06:00
parent 65745422a8
commit 9b6efcd2e2
1 changed files with 8 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
arch/x86/lguest/boot.c
View File

@@ -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, * For a single GDT entry which changes, we simply change our copy and
* then tell the Host to reload the entire thing. This operation is so rare * then tell the host about it.
* that this naive implementation is reasonable.
*/ */
static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum, static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
const void *desc, int type) 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 * 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) static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
{ {