[RFC PATCH 2/4] KVM: x86: emulate sldt and str

[Paolo Bonzini <pbonzini@redhat.com>]

These will be used to emulate UMIP through VMX descriptor-table
vmexits.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/emulate.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a2f24af3c999..3e09c7461ba8 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3577,15 +3577,20 @@ static int em_rdmsr(struct x86_emulate_ctxt *ctxt)
 	return X86EMUL_CONTINUE;
 }
 
+static int em_store_sreg(struct x86_emulate_ctxt *ctxt, int segment)
+{
+	ctxt->dst.val = get_segment_selector(ctxt, segment);
+	if (ctxt->dst.bytes == 4 && ctxt->dst.type == OP_MEM)
+		ctxt->dst.bytes = 2;
+	return X86EMUL_CONTINUE;
+}
+
 static int em_mov_rm_sreg(struct x86_emulate_ctxt *ctxt)
 {
 	if (ctxt->modrm_reg > VCPU_SREG_GS)
 		return emulate_ud(ctxt);
 
-	ctxt->dst.val = get_segment_selector(ctxt, ctxt->modrm_reg);
-	if (ctxt->dst.bytes == 4 && ctxt->dst.type == OP_MEM)
-		ctxt->dst.bytes = 2;
-	return X86EMUL_CONTINUE;
+	return em_store_sreg(ctxt, ctxt->modrm_reg);
 }
 
 static int em_mov_sreg_rm(struct x86_emulate_ctxt *ctxt)
@@ -3603,6 +3608,11 @@ static int em_mov_sreg_rm(struct x86_emulate_ctxt *ctxt)
 	return load_segment_descriptor(ctxt, sel, ctxt->modrm_reg);
 }
 
+static int em_sldt(struct x86_emulate_ctxt *ctxt)
+{
+	return em_store_sreg(ctxt, VCPU_SREG_LDTR);
+}
+
 static int em_lldt(struct x86_emulate_ctxt *ctxt)
 {
 	u16 sel = ctxt->src.val;
@@ -3612,6 +3622,11 @@ static int em_lldt(struct x86_emulate_ctxt *ctxt)
 	return load_segment_descriptor(ctxt, sel, VCPU_SREG_LDTR);
 }
 
+static int em_str(struct x86_emulate_ctxt *ctxt)
+{
+	return em_store_sreg(ctxt, VCPU_SREG_TR);
+}
+
 static int em_ltr(struct x86_emulate_ctxt *ctxt)
 {
 	u16 sel = ctxt->src.val;
@@ -4161,8 +4176,8 @@ static const struct opcode group5[] = {
 };
 
 static const struct opcode group6[] = {
-	DI(Prot | DstMem,	sldt),
-	DI(Prot | DstMem,	str),
+	II(Prot | DstMem,	   em_sldt, sldt),
+	II(Prot | DstMem,	   em_str, str),
 	II(Prot | Priv | SrcMem16, em_lldt, lldt),
 	II(Prot | Priv | SrcMem16, em_ltr, ltr),
 	N, N, N, N,
-- 
1.8.3.1