[RFC PATCH v1 09/34] KVM: x86: add .control_ept_view()

[Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>]

From: Ștefan Șicleru <ssicleru@xxxxxxxxxxxxxxx>

This will be used by the introspection tool to control the EPT views to
which the guest is allowed to switch.

Signed-off-by: Ștefan Șicleru <ssicleru@xxxxxxxxxxxxxxx>
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/vmx/vmx.c          | 18 +++++++++++++++++-
 arch/x86/kvm/vmx/vmx.h          |  2 ++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 300f7fc43987..5e241863153f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1310,6 +1310,7 @@ struct kvm_x86_ops {
 	bool (*get_eptp_switching_status)(void);
 	u16 (*get_ept_view)(struct kvm_vcpu *vcpu);
 	int (*set_ept_view)(struct kvm_vcpu *vcpu, u16 view);
+	int (*control_ept_view)(struct kvm_vcpu *vcpu, u16 view, u8 visible);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 0d39487ce5c6..cbc943d217e3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3138,8 +3138,11 @@ static void vmx_construct_eptp_with_index(struct kvm_vcpu *vcpu,
 	if (!eptp_list)
 		return;
 
-	eptp_list[view] = construct_eptp(vcpu,
+	if (test_bit(view, &vmx->allowed_views))
+		eptp_list[view] = construct_eptp(vcpu,
 				vcpu->arch.mmu->root_hpa_altviews[view]);
+	else
+		eptp_list[view] = (~0ULL);
 }
 
 static void vmx_construct_eptp_list(struct kvm_vcpu *vcpu)
@@ -4395,6 +4398,18 @@ static int vmx_set_ept_view(struct kvm_vcpu *vcpu, u16 view)
 	return 0;
 }
 
+static int vmx_control_ept_view(struct kvm_vcpu *vcpu, u16 view, u8 visible)
+{
+	if (visible)
+		set_bit(view, &to_vmx(vcpu)->allowed_views);
+	else
+		clear_bit(view, &to_vmx(vcpu)->allowed_views);
+
+	vmx_construct_eptp_with_index(vcpu, view);
+
+	return 0;
+}
+
 #define VMX_XSS_EXIT_BITMAP 0
 
 /*
@@ -8284,6 +8299,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.get_eptp_switching_status = vmx_get_eptp_switching_status,
 	.get_ept_view = vmx_get_ept_view,
 	.set_ept_view = vmx_set_ept_view,
+	.control_ept_view = vmx_control_ept_view,
 };
 
 static __init int hardware_setup(void)
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 4e2f86458ca2..38d50fc7357b 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -300,6 +300,8 @@ struct vcpu_vmx {
 	struct page *eptp_list_pg;
 	/* The view this vcpu operates on. */
 	u16 view;
+	/* Visible EPT views bitmap for in-guest VMFUNC. */
+	unsigned long allowed_views;
 };
 
 enum ept_pointers_status {