lguest: fix guest crash on non-linear addresses in gdt pvops

Fixes guest crash 'lguest: bad read address 0x4800000 len 256'

The new per-cpu allocator ends up handing a non-linear address to
write_gdt_entry.  We do __pa() on it, and hand it to the host, which
kills us.

I've long wanted to make the hypercall "LOAD_GDT_ENTRY" to match the IDT
code, but had no pressing reason until now.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: lguest@ozlabs.org

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
index 0f4ee7148afe..faae1996487b 100644
--- a/arch/x86/include/asm/lguest_hcall.h
+++ b/arch/x86/include/asm/lguest_hcall.h
@@ -5,7 +5,6 @@
 #define LHCALL_FLUSH_ASYNC      0
 #define LHCALL_LGUEST_INIT      1
 #define LHCALL_SHUTDOWN         2
-#define LHCALL_LOAD_GDT         3
 #define LHCALL_NEW_PGTABLE      4
 #define LHCALL_FLUSH_TLB        5
 #define LHCALL_LOAD_IDT_ENTRY   6
@@ -17,6 +16,7 @@
 #define LHCALL_SET_PMD          15
 #define LHCALL_LOAD_TLS         16
 #define LHCALL_NOTIFY           17
+#define LHCALL_LOAD_GDT_ENTRY   18
 
 #define LGUEST_TRAP_ENTRY 0x1F