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Commit 3964994b authored by Eric Sesterhenn / Snakebyte's avatar Eric Sesterhenn / Snakebyte Committed by Avi Kivity
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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: default avatarEric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 5008fdf5

drivers/kvm/vmx.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1182,7 +1182,7 @@ static void inject_rmode_irq(struct kvm_vcpu *vcpu, int irq) 
	u16 sp =  vmcs_readl(GUEST_RSP);

	u16 sp =  vmcs_readl(GUEST_RSP);

	u32 ss_limit = vmcs_read32(GUEST_SS_LIMIT);

	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",

		vcpu_printf(vcpu, "%s: #SS, rsp 0x%lx ss 0x%lx limit 0x%x\n",

			    __FUNCTION__,

			    __FUNCTION__,

			    vmcs_readl(GUEST_RSP),

			    vmcs_readl(GUEST_RSP),