[PATCH v3 24/27] KVM: nVMX: Add a prerequisite to existence of VMCS fields
From: Xin Li (Intel)
Date: Tue Oct 01 2024 - 01:06:43 EST
Add a prerequisite to existence of VMCS fields as some of them exist
only on processors that support certain CPU features.
This is required to fix KVM unit test VMX_VMCS_ENUM.MAX_INDEX.
Originally-by: Lei Wang <lei4.wang@xxxxxxxxx>
Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 19 +++++++++++++++++--
arch/x86/kvm/vmx/nested_vmcs_fields.h | 13 +++++++++++++
2 files changed, 30 insertions(+), 2 deletions(-)
create mode 100644 arch/x86/kvm/vmx/nested_vmcs_fields.h
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7f3ac558ace5..4529fd635385 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -49,6 +49,21 @@ static unsigned long *vmx_bitmap[VMX_BITMAP_NR];
#define vmx_vmread_bitmap (vmx_bitmap[VMX_VMREAD_BITMAP])
#define vmx_vmwrite_bitmap (vmx_bitmap[VMX_VMWRITE_BITMAP])
+static bool nested_cpu_has_vmcs_field(struct kvm_vcpu *vcpu, u16 vmcs_field_encoding)
+{
+ switch (vmcs_field_encoding) {
+#define HAS_VMCS_FIELD(x, c) \
+ case x: \
+ return c;
+#define HAS_VMCS_FIELD_RANGE(x, y, c) \
+ case x...y: \
+ return c;
+#include "nested_vmcs_fields.h"
+ default:
+ return true;
+ }
+}
+
struct shadow_vmcs_field {
u16 encoding;
u16 offset;
@@ -5565,7 +5580,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
return nested_vmx_failInvalid(vcpu);
offset = get_vmcs12_field_offset(field);
- if (offset < 0)
+ if (offset < 0 || !nested_cpu_has_vmcs_field(vcpu, field))
return nested_vmx_fail(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
if (!is_guest_mode(vcpu) && is_vmcs12_ext_field(field))
@@ -5691,7 +5706,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
field = kvm_register_read(vcpu, (((instr_info) >> 28) & 0xf));
offset = get_vmcs12_field_offset(field);
- if (offset < 0)
+ if (offset < 0 || !nested_cpu_has_vmcs_field(vcpu, field))
return nested_vmx_fail(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
/*
diff --git a/arch/x86/kvm/vmx/nested_vmcs_fields.h b/arch/x86/kvm/vmx/nested_vmcs_fields.h
new file mode 100644
index 000000000000..fcd6c32dce31
--- /dev/null
+++ b/arch/x86/kvm/vmx/nested_vmcs_fields.h
@@ -0,0 +1,13 @@
+#if !defined(HAS_VMCS_FIELD) && !defined(HAS_VMCS_FIELD_RANGE)
+BUILD_BUG_ON(1)
+#endif
+
+#ifndef HAS_VMCS_FIELD
+#define HAS_VMCS_FIELD(x, c)
+#endif
+#ifndef HAS_VMCS_FIELD_RANGE
+#define HAS_VMCS_FIELD_RANGE(x, y, c)
+#endif
+
+#undef HAS_VMCS_FIELD
+#undef HAS_VMCS_FIELD_RANGE
--
2.46.2