KVM: SVM: Add intercept check for accessing dr registers
This patch adds the intercept checks for instruction
accessing the debug registers.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d2e7775..cd9ed9f 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -509,6 +509,11 @@
return X86EMUL_PROPAGATE_FAULT;
}
+static int emulate_db(struct x86_emulate_ctxt *ctxt)
+{
+ return emulate_exception(ctxt, DB_VECTOR, 0, false);
+}
+
static int emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
{
return emulate_exception(ctxt, GP_VECTOR, err, true);
@@ -2534,6 +2539,47 @@
return X86EMUL_CONTINUE;
}
+static int check_dr7_gd(struct x86_emulate_ctxt *ctxt)
+{
+ unsigned long dr7;
+
+ ctxt->ops->get_dr(7, &dr7, ctxt->vcpu);
+
+ /* Check if DR7.Global_Enable is set */
+ return dr7 & (1 << 13);
+}
+
+static int check_dr_read(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ int dr = c->modrm_reg;
+ u64 cr4;
+
+ if (dr > 7)
+ return emulate_ud(ctxt);
+
+ cr4 = ctxt->ops->get_cr(4, ctxt->vcpu);
+ if ((cr4 & X86_CR4_DE) && (dr == 4 || dr == 5))
+ return emulate_ud(ctxt);
+
+ if (check_dr7_gd(ctxt))
+ return emulate_db(ctxt);
+
+ return X86EMUL_CONTINUE;
+}
+
+static int check_dr_write(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ u64 new_val = c->src.val64;
+ int dr = c->modrm_reg;
+
+ if ((dr == 6 || dr == 7) && (new_val & 0xffffffff00000000ULL))
+ return emulate_gp(ctxt, 0);
+
+ return check_dr_read(ctxt);
+}
+
#define D(_y) { .flags = (_y) }
#define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i }
#define DIP(_y, _i, _p) { .flags = (_y), .intercept = x86_intercept_##_i, \
@@ -2728,9 +2774,9 @@
N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, N,
/* 0x20 - 0x2F */
DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
- D(ModRM | DstMem | Priv | Op3264),
+ DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read),
DIP(ModRM | SrcMem | Priv | Op3264, cr_write, check_cr_write),
- D(ModRM | SrcMem | Priv | Op3264),
+ DIP(ModRM | SrcMem | Priv | Op3264, dr_write, check_dr_write),
N, N, N, N,
N, N, N, N, N, N, N, N,
/* 0x30 - 0x3F */
@@ -3818,12 +3864,6 @@
c->dst.val = ops->get_cr(c->modrm_reg, ctxt->vcpu);
break;
case 0x21: /* mov from dr to reg */
- if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
- (c->modrm_reg == 4 || c->modrm_reg == 5)) {
- emulate_ud(ctxt);
- rc = X86EMUL_PROPAGATE_FAULT;
- goto done;
- }
ops->get_dr(c->modrm_reg, &c->dst.val, ctxt->vcpu);
break;
case 0x22: /* mov reg, cr */
@@ -3835,13 +3875,6 @@
c->dst.type = OP_NONE;
break;
case 0x23: /* mov from reg to dr */
- if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
- (c->modrm_reg == 4 || c->modrm_reg == 5)) {
- emulate_ud(ctxt);
- rc = X86EMUL_PROPAGATE_FAULT;
- goto done;
- }
-
if (ops->set_dr(c->modrm_reg, c->src.val &
((ctxt->mode == X86EMUL_MODE_PROT64) ?
~0ULL : ~0U), ctxt->vcpu) < 0) {
