From e8861cfe2c75bdce36655b64d7ce02c2b31b604d Mon Sep 17 00:00:00 2001
From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Wed, 14 Apr 2010 16:57:11 +0200
Subject: [PATCH] KVM: x86: Fix TSS size check for 16-bit tasks
A 16-bit TSS is only 44 bytes long. So make sure to test for the correct
size on task switch.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/x86.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 45aa90f8cc57..3c4ca98ad27f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5126,6 +5126,7 @@ 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);
@@ -5148,7 +5149,10 @@ 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;
}
--
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