On 2/26/2024 4:27 PM, isaku.yamahata@xxxxxxxxx wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
TDX protects TDX guest state from VMM. Implement access methods for TDX
guest state to ignore them or return zero. Because those methods can be
called by kvm ioctls to set/get cpu registers, they don't have KVM_BUG_ON
except one method.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/kvm/vmx/main.c | 289 +++++++++++++++++++++++++++++++++----
arch/x86/kvm/vmx/tdx.c | 48 +++++-
arch/x86/kvm/vmx/x86_ops.h | 13 ++
3 files changed, 321 insertions(+), 29 deletions(-)
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 84d2dc818cf7..9fb3f28d8259 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -375,6 +375,200 @@ static void vt_vcpu_deliver_init(struct kvm_vcpu *vcpu)
kvm_vcpu_deliver_init(vcpu);
}
+static void vt_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
+{
+ if (is_td_vcpu(vcpu))
+ return;
+
+ vmx_vcpu_after_set_cpuid(vcpu);
+}
+
+static void vt_update_exception_bitmap(struct kvm_vcpu *vcpu)
+{
+ if (is_td_vcpu(vcpu))
+ return;
+
+ vmx_update_exception_bitmap(vcpu);
+}
+
+static u64 vt_get_segment_base(struct kvm_vcpu *vcpu, int seg)
+{
+ if (is_td_vcpu(vcpu))
+ return tdx_get_segment_base(vcpu, seg);
Could just return 0?
Not need to add a function, since it's only called here and it's more
straight forward to read the code without jump to the definition of
these functions.
Similarly, we can use open code for tdx_get_cpl(), tdx_get_rflags() and
tdx_get_segment(), which return 0 or memset with 0.
+
+ return vmx_get_segment_base(vcpu, seg);
+}
+
[...]
+int tdx_get_cpl(struct kvm_vcpu *vcpu)
+{
+ return 0;
+}
+
[...]
+
+unsigned long tdx_get_rflags(struct kvm_vcpu *vcpu)
+{
+ return 0;
+}
+
+u64 tdx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
+{
+ return 0;
+}
+
+void tdx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)
+{
+ memset(var, 0, sizeof(*var));
+}
+
static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
{
struct kvm_tdx_capabilities __user *user_caps;
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 7c63b2b48125..727c4d418601 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -169,6 +169,12 @@ bool tdx_has_emulated_msr(u32 index, bool write);
int tdx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
int tdx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
+int tdx_get_cpl(struct kvm_vcpu *vcpu);
+void tdx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg);
+unsigned long tdx_get_rflags(struct kvm_vcpu *vcpu);
+u64 tdx_get_segment_base(struct kvm_vcpu *vcpu, int seg);
+void tdx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
+
int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
void tdx_flush_tlb(struct kvm_vcpu *vcpu);
@@ -221,6 +227,13 @@ static inline bool tdx_has_emulated_msr(u32 index, bool write) { return false; }
static inline int tdx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) { return 1; }
static inline int tdx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) { return 1; }
+static inline int tdx_get_cpl(struct kvm_vcpu *vcpu) { return 0; }
+static inline void tdx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) {}
+static inline unsigned long tdx_get_rflags(struct kvm_vcpu *vcpu) { return 0; }
+static inline u64 tdx_get_segment_base(struct kvm_vcpu *vcpu, int seg) { return 0; }
+static inline void tdx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var,
+ int seg) {}
+
static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
static inline void tdx_flush_tlb(struct kvm_vcpu *vcpu) {}
