[STABLE] KVM: x86: Fix TSS size check for 16-bit tasks

Commit Message

Jan Kiszka April 14, 2010, 2:57 p.m. UTC

None

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e46282a..35eabd8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5145,6 +5145,7 @@  int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
 	int ret = 0;
 	u32 old_tss_base = get_segment_base(vcpu, VCPU_SREG_TR);
 	u16 old_tss_sel = get_segment_selector(vcpu, VCPU_SREG_TR);
+	u32 desc_limit;
 
 	old_tss_base = kvm_mmu_gva_to_gpa_write(vcpu, old_tss_base, NULL);
 
@@ -5167,7 +5168,10 @@  int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
 		}
 	}
 
-	if (!nseg_desc.p || get_desc_limit(&nseg_desc) < 0x67) {
+	desc_limit = get_desc_limit(&nseg_desc);
+	if (!nseg_desc.p ||
+	    ((desc_limit < 0x67 && (nseg_desc.type & 8)) ||
+	     desc_limit < 0x2b)) {
 		kvm_queue_exception_e(vcpu, TS_VECTOR, tss_selector & 0xfffc);
 		return 1;
 	}