[PATCH] kvm, svm: Intercept #DF on AMD

[Borislav Petkov]

Thanks Joro for the initial patch.

Originally-by: Joerg Roedel <joro@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
 arch/x86/kvm/svm.c   |  9 +++++++++
 arch/x86/kvm/trace.h | 15 +++++++++++++++
 arch/x86/kvm/x86.c   |  1 +
 3 files changed, 25 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ec8366c5cfea..30a83f219aa5 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1101,6 +1101,7 @@ static void init_vmcb(struct vcpu_svm *svm)
 	set_exception_intercept(svm, PF_VECTOR);
 	set_exception_intercept(svm, UD_VECTOR);
 	set_exception_intercept(svm, MC_VECTOR);
+	set_exception_intercept(svm, DF_VECTOR);
 
 	set_intercept(svm, INTERCEPT_INTR);
 	set_intercept(svm, INTERCEPT_NMI);
@@ -1784,6 +1785,13 @@ static int ud_interception(struct vcpu_svm *svm)
 	return 1;
 }
 
+static int df_interception(struct vcpu_svm *svm)
+{
+	trace_kvm_df(kvm_rip_read(&svm->vcpu));
+
+	return 1;
+}
+
 static void svm_fpu_activate(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -3324,6 +3332,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = {
 	[SVM_EXIT_EXCP_BASE + PF_VECTOR]	= pf_interception,
 	[SVM_EXIT_EXCP_BASE + NM_VECTOR]	= nm_interception,
 	[SVM_EXIT_EXCP_BASE + MC_VECTOR]	= mc_interception,
+	[SVM_EXIT_EXCP_BASE + DF_VECTOR]	= df_interception,
 	[SVM_EXIT_INTR]				= intr_interception,
 	[SVM_EXIT_NMI]				= nmi_interception,
 	[SVM_EXIT_SMI]				= nop_on_interception,
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 33574c95220d..8ac01d218443 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -88,6 +88,21 @@ TRACE_EVENT(kvm_hv_hypercall,
 		  __entry->outgpa)
 );
 
+TRACE_EVENT(kvm_df,
+	TP_PROTO(unsigned long rip),
+	TP_ARGS(rip),
+
+	TP_STRUCT__entry(
+		__field(	unsigned long,	rip	)
+	),
+
+	TP_fast_assign(
+		__entry->rip	= rip;
+	),
+
+	TP_printk("rip: 0x%lx", __entry->rip)
+);
+
 /*
  * Tracepoint for PIO.
  */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f32a02578c0d..9e6056dcdaea 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7576,3 +7576,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_invlpga);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_skinit);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_intercepts);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_write_tsc_offset);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_df);
-- 
2.0.0


--uAKRQypu60I7Lcqm--
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