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Subject[PATCH 2/9] KVM: x86: Emulator ignores LDTR/TR extended base on LLDT/LTR
Date
The current implementation ignores the LDTR/TR base high 32-bits on long-mode.
As a result the loaded segment descriptor may be incorrect.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
---
arch/x86/kvm/emulate.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8ec4a3e..136088f 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1422,6 +1422,7 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
ulong desc_addr;
int ret;
u16 dummy;
+ u32 base3 = 0;

memset(&seg_desc, 0, sizeof seg_desc);

@@ -1538,9 +1539,14 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
ret = write_segment_descriptor(ctxt, selector, &seg_desc);
if (ret != X86EMUL_CONTINUE)
return ret;
+ } else if (ctxt->mode == X86EMUL_MODE_PROT64) {
+ ret = ctxt->ops->read_std(ctxt, desc_addr+8, &base3,
+ sizeof(base3), &ctxt->exception);
+ if (ret != X86EMUL_CONTINUE)
+ return ret;
}
load:
- ctxt->ops->set_segment(ctxt, selector, &seg_desc, 0, seg);
+ ctxt->ops->set_segment(ctxt, selector, &seg_desc, base3, seg);
return X86EMUL_CONTINUE;
exception:
emulate_exception(ctxt, err_vec, err_code, true);
--
1.9.1


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