This patch adds the intercept checks for instruction
accessing the debug registers.
Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
arch/x86/include/asm/kvm_emulate.h | 2 +
arch/x86/kvm/emulate.c | 63 +++++++++++++++++++++++++++--------
arch/x86/kvm/svm.c | 6 +++
3 files changed, 56 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 6922200..9b11edd 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -303,6 +303,8 @@ enum x86_intercept {
x86_intercept_clts,
x86_intercept_lmsw,
x86_intercept_smsw,
+ x86_intercept_dr_read,
+ x86_intercept_dr_write,
x86_intercept_lidt,
x86_intercept_sidt,
x86_intercept_lgdt,
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e37630b..1f9b2e2 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -499,6 +499,11 @@ static int emulate_exception(struct x86_emulate_ctxt *ctxt, int vec,
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);
@@ -2437,6 +2442,47 @@ static int em_check_perm_cr_write(struct x86_emulate_ctxt *ctxt)
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 em_check_perm_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 em_check_perm_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 em_check_perm_dr_read(ctxt);
+}
+
#define D(_y) { .flags = (_y) }
#define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i }
#define DIP(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i, \
@@ -2628,9 +2674,9 @@ static struct opcode twobyte_table[256] = {
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),
- D(ModRM | DstMem | Priv | Op3264),
+ DIP(ModRM | DstMem | Priv | Op3264, dr_read),
DIP(ModRM | SrcMem | Priv | Op3264, cr_write),
- D(ModRM | SrcMem | Priv | Op3264),
+ DIP(ModRM | SrcMem | Priv | Op3264, dr_write),
N, N, N, N,
N, N, N, N, N, N, N, N,
/* 0x30 - 0x3F */
@@ -3683,12 +3729,6 @@ twobyte_insn:
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 */
@@ -3700,13 +3740,6 @@ twobyte_insn:
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) {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ff4ed36..381b038 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3882,6 +3882,8 @@ static struct __x86_intercept {
[x86_intercept_clts] = POST_EX(SVM_EXIT_WRITE_CR0),
[x86_intercept_lmsw] = POST_EX(SVM_EXIT_WRITE_CR0),
[x86_intercept_smsw] = POST_EX(SVM_EXIT_READ_CR0),
+ [x86_intercept_dr_read] = POST_EX(SVM_EXIT_READ_DR0),
+ [x86_intercept_dr_write] = POST_EX(SVM_EXIT_WRITE_DR0),
};
#undef POST_EX
@@ -3939,6 +3941,10 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
break;
}
+ case SVM_EXIT_READ_DR0:
+ case SVM_EXIT_WRITE_DR0:
+ icpt_info.exit_code += info->modrm_reg;
+ break;
default:
break;
}
--
1.7.1
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