KVM: nSVM: introduce struct vmcb_ctrl_area_cached

This structure will replace vmcb_control_area in
svm_nested_state, providing only the fields that are actually
used by the nested state. This avoids having and copying around
uninitialized fields. The cost of this, however, is that all
functions (in this case vmcb_is_intercept) expect the old
structure, so they need to be duplicated.

In addition, in svm_get_nested_state() user space expects a
vmcb_control_area struct, so we need to copy back all fields
in a temporary structure before copying it to userspace.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211103140527.752797-7-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 35 insertions, 4 deletions

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 3f44ec79597b..929bd60d754d 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -114,6 +114,31 @@ struct vmcb_save_area_cached {
 	u64 dr6;
 };
 
+struct vmcb_ctrl_area_cached {
+	u32 intercepts[MAX_INTERCEPT];
+	u16 pause_filter_thresh;
+	u16 pause_filter_count;
+	u64 iopm_base_pa;
+	u64 msrpm_base_pa;
+	u64 tsc_offset;
+	u32 asid;
+	u8 tlb_ctl;
+	u32 int_ctl;
+	u32 int_vector;
+	u32 int_state;
+	u32 exit_code;
+	u32 exit_code_hi;
+	u64 exit_info_1;
+	u64 exit_info_2;
+	u32 exit_int_info;
+	u32 exit_int_info_err;
+	u64 nested_ctl;
+	u32 event_inj;
+	u32 event_inj_err;
+	u64 nested_cr3;
+	u64 virt_ext;
+};
+
 struct svm_nested_state {
 	struct kvm_vmcb_info vmcb02;
 	u64 hsave_msr;
@@ -129,7 +154,7 @@ struct svm_nested_state {
 	bool nested_run_pending;
 
 	/* cache for control fields of the guest */
-	struct vmcb_control_area ctl;
+	struct vmcb_ctrl_area_cached ctl;
 
 	/*
 	 * Note: this struct is not kept up-to-date while L2 runs; it is only
@@ -318,6 +343,12 @@ static inline bool vmcb_is_intercept(struct vmcb_control_area *control, u32 bit)
 	return test_bit(bit, (unsigned long *)&control->intercepts);
 }
 
+static inline bool vmcb12_is_intercept(struct vmcb_ctrl_area_cached *control, u32 bit)
+{
+	WARN_ON_ONCE(bit >= 32 * MAX_INTERCEPT);
+	return test_bit(bit, (unsigned long *)&control->intercepts);
+}
+
 static inline void set_dr_intercepts(struct vcpu_svm *svm)
 {
 	struct vmcb *vmcb = svm->vmcb01.ptr;
@@ -470,17 +501,17 @@ static inline bool nested_svm_virtualize_tpr(struct kvm_vcpu *vcpu)
 
 static inline bool nested_exit_on_smi(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_SMI);
+	return vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_SMI);
 }
 
 static inline bool nested_exit_on_intr(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_INTR);
+	return vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_INTR);
 }
 
 static inline bool nested_exit_on_nmi(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_NMI);
+	return vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_NMI);
 }
 
 int enter_svm_guest_mode(struct kvm_vcpu *vcpu,