[PATCH v16 14/20] KVM: selftests: Set entry point for TDX guest code

[Lisa Wang]

From: Sagi Shahar <sagis@xxxxxxxxxx>

Since the rip register is inaccessible for TDX VMs, we need a different
way to set the guest entry point for TDX VMs. This is done by writing
the guest code address to a predefined location in the guest memory and
loading it into rip as part of the TDX boot code.

Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>
Reviewed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
---
 tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h |  1 +
 tools/testing/selftests/kvm/lib/x86/processor.c        | 10 +++++++---
 tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c     | 10 ++++++++++
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
index 9d951f67b3b5..1cc876891589 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
@@ -72,5 +72,6 @@ void tdx_vm_setup_boot_code_region(struct kvm_vm *vm);
 void tdx_vm_setup_boot_parameters_region(struct kvm_vm *vm, u32 nr_runnable_vcpus);
 void tdx_vm_load_common_boot_parameters(struct kvm_vm *vm);
 void tdx_vcpu_init(struct kvm_vcpu *vcpu);
+void tdx_vcpu_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code);
 
 #endif /* SELFTESTS_TDX_TDX_UTIL_H */
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index 110d23e50bcc..11db6a3b0366 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -853,9 +853,13 @@ void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
 {
 	struct kvm_regs regs;
 
-	vcpu_regs_get(vcpu, &regs);
-	regs.rip = (unsigned long) guest_code;
-	vcpu_regs_set(vcpu, &regs);
+	if (is_tdx_vm(vcpu->vm)) {
+		tdx_vcpu_set_entry_point(vcpu, guest_code);
+	} else {
+		vcpu_regs_get(vcpu, &regs);
+		regs.rip = (unsigned long)guest_code;
+		vcpu_regs_set(vcpu, &regs);
+	}
 }
 
 struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
index 84127618f05c..324f3c41aa61 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
@@ -118,6 +118,16 @@ void tdx_vcpu_init(struct kvm_vcpu *vcpu)
 	tdx_vcpu_load_boot_parameters(vcpu);
 }
 
+void tdx_vcpu_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
+{
+	struct td_boot_parameters *params =
+		addr_gpa2hva(vcpu->vm, TD_BOOT_PARAMETERS_GPA);
+	struct td_per_vcpu_parameters *vcpu_params =
+		&params->per_vcpu[vcpu->id];
+
+	vcpu_params->guest_code = (u64)guest_code;
+}
+
 static const struct kvm_tdx_capabilities *tdx_read_capabilities(struct kvm_vm *vm)
 {
 	static struct kvm_tdx_capabilities *tdx_cap;

-- 
2.56.0.455.g6c5a503b38-goog