commit 3964994bb5ba85a3d8b54ae618f7be1cecce916d
author Eric Sesterhenn / Snakebyte <snakebyte@gmx.de> Mon Apr 09 16:15:05 2007 +0200
committer Avi Kivity <avi@qumranet.com> Thu May 03 10:52:29 2007 +0300
tree d093a2be86855e37abe7783e257eac4d9eb0ae73
parent 5008fdf5b6a31240da060c0867d8f16f08ce2384

KVM: Fix overflow bug in overflow detection code

The expression

   sp - 6 < sp

where sp is a u16 is undefined in C since 'sp - 6' is promoted to int,
and signed overflow is undefined in C.  gcc 4.2 actually warns about it.
Replace with a simpler test.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/vmx.c

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 61a6116..8c0115b 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1182,7 +1182,7 @@
 	u16 sp =  vmcs_readl(GUEST_RSP);
 	u32 ss_limit = vmcs_read32(GUEST_SS_LIMIT);
 
-	if (sp > ss_limit || sp - 6 > sp) {
+	if (sp > ss_limit || sp < 6 ) {
 		vcpu_printf(vcpu, "%s: #SS, rsp 0x%lx ss 0x%lx limit 0x%x\n",
 			    __FUNCTION__,
 			    vmcs_readl(GUEST_RSP),