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@xxxxxxxxxxx>
---
This is a backport of 8f2d524 from master. It applies at least down to
2.6.32 and should be considered for the stable queues.
arch/x86/kvm/x86.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)
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;
}
--
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