linux-kernel - [RFC PATCH v2 03/10] KVM: TDX: Add base implementation for tdx_vm_move_enc_context

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Message-ID: <c55644ec81c22e7239d52f97e744eb4bafeccac3.1749672978.git.afranji@google.com>
Date: Wed, 11 Jun 2025 21:16:30 +0000
From: Ryan Afranji <afranji@...gle.com>
To: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org
Cc: sagis@...gle.com, bp@...en8.de, chao.p.peng@...ux.intel.com, 
	dave.hansen@...ux.intel.com, dmatlack@...gle.com, erdemaktas@...gle.com, 
	isaku.yamahata@...el.com, kai.huang@...el.com, mingo@...hat.com, 
	pbonzini@...hat.com, seanjc@...gle.com, tglx@...utronix.de, 
	zhi.wang.linux@...il.com, ackerleytng@...gle.com, andrew.jones@...ux.dev, 
	david@...hat.com, hpa@...or.com, kirill.shutemov@...ux.intel.com, 
	linux-kselftest@...r.kernel.org, tabba@...gle.com, vannapurve@...gle.com, 
	yan.y.zhao@...el.com, rick.p.edgecombe@...el.com, 
	Ryan Afranji <afranji@...gle.com>
Subject: [RFC PATCH v2 03/10] KVM: TDX: Add base implementation for tdx_vm_move_enc_context_from

From: Sagi Shahar <sagis@...gle.com>

This should mostly match the logic in sev_vm_move_enc_context_from.

Signed-off-by: Sagi Shahar <sagis@...gle.com>
Signed-off-by: Ryan Afranji <afranji@...gle.com>
---
 arch/x86/kvm/vmx/main.c    | 12 +++++++++++-
 arch/x86/kvm/vmx/tdx.c     | 24 ++++++++++++++++++++++++
 arch/x86/kvm/vmx/x86_ops.h |  1 +
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index d1e02e567b57..125af25fd09a 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -879,6 +879,14 @@ static int vt_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
 	return 0;
 }
 
+static int vt_move_enc_context_from(struct kvm *kvm, struct kvm *source_kvm)
+{
+	if (!is_td(kvm))
+		return -ENOTTY;
+
+	return tdx_vm_move_enc_context_from(kvm, source_kvm);
+}
+
 #define vt_op(name) vt_##name
 #define vt_op_tdx_only(name) vt_##name
 #else /* CONFIG_KVM_INTEL_TDX */
@@ -1044,7 +1052,9 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.mem_enc_ioctl = vt_op_tdx_only(mem_enc_ioctl),
 	.vcpu_mem_enc_ioctl = vt_op_tdx_only(vcpu_mem_enc_ioctl),
 
-	.private_max_mapping_level = vt_op_tdx_only(gmem_private_max_mapping_level)
+	.private_max_mapping_level = vt_op_tdx_only(gmem_private_max_mapping_level),
+
+	.vm_move_enc_context_from = vt_move_enc_context_from
 };
 
 struct kvm_x86_init_ops vt_init_ops __initdata = {
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index b952bc673271..07583a11d6e3 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -626,6 +626,7 @@ int tdx_vm_init(struct kvm *kvm)
 	kvm->arch.has_protected_state = true;
 	kvm->arch.has_private_mem = true;
 	kvm->arch.disabled_quirks |= KVM_X86_QUIRK_IGNORE_GUEST_PAT;
+	kvm->arch.use_vm_enc_ctxt_op = true;
 
 	/*
 	 * Because guest TD is protected, VMM can't parse the instruction in TD.
@@ -3524,3 +3525,26 @@ int __init tdx_bringup(void)
 	enable_tdx = 0;
 	return 0;
 }
+
+static __always_inline bool tdx_finalized(struct kvm *kvm)
+{
+	struct kvm_tdx *tdx_kvm = to_kvm_tdx(kvm);
+
+	return tdx_kvm->state == TD_STATE_RUNNABLE;
+}
+
+static int tdx_migrate_from(struct kvm *dst, struct kvm *src)
+{
+	return -EINVAL;
+}
+
+int tdx_vm_move_enc_context_from(struct kvm *kvm, struct kvm *src_kvm)
+{
+	if (!is_td(kvm) || !is_td(src_kvm))
+		return -EINVAL;
+
+	if (tdx_finalized(kvm) || !tdx_finalized(src_kvm))
+		return -EINVAL;
+
+	return tdx_migrate_from(kvm, src_kvm);
+}
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index b4596f651232..001f1540a560 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -164,6 +164,7 @@ void tdx_flush_tlb_current(struct kvm_vcpu *vcpu);
 void tdx_flush_tlb_all(struct kvm_vcpu *vcpu);
 void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);
 int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn);
+int tdx_vm_move_enc_context_from(struct kvm *kvm, struct kvm *source_kvm);
 #endif
 
 #endif /* __KVM_X86_VMX_X86_OPS_H */
-- 
2.50.0.rc1.591.g9c95f17f64-goog