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Commit 9b6efcd2 authored by Rusty Russell's avatar Rusty Russell
Browse files

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: default avatarRusty Russell <rusty@rustcorp.com.au>
Reported by: Eviatar Khen <eviatarkhen@gmail.com>
parent 65745422

arch/x86/lguest/boot.c

+8 −5
Original line number Diff line number Diff line
@@ -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)

{