[PATCH 4/6] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests

[Dexuan Cui <decui@xxxxxxxxxxxxx>]

No logic change to SNP/VBS guests.

Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
---
 arch/x86/hyperv/ivm.c              |  7 +++++++
 arch/x86/include/asm/hyperv-tlfs.h |  3 ++-
 arch/x86/include/asm/mshyperv.h    |  3 +++
 arch/x86/kernel/cpu/mshyperv.c     | 18 ++++++++++++++++--
 drivers/hv/hv_common.c             |  6 ++++++
 5 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 1dbcbd9da74d..0c219f163f71 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -269,6 +269,13 @@ bool hv_isolation_type_snp(void)
 	return static_branch_unlikely(&isolation_type_snp);
 }
 
+DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
+
+bool hv_isolation_type_tdx(void)
+{
+	return static_branch_unlikely(&isolation_type_tdx);
+}
+
 /*
  * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
  *
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 6d9368ea3701..6c0a04d078f5 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -161,7 +161,8 @@
 enum hv_isolation_type {
 	HV_ISOLATION_TYPE_NONE	= 0,
 	HV_ISOLATION_TYPE_VBS	= 1,
-	HV_ISOLATION_TYPE_SNP	= 2
+	HV_ISOLATION_TYPE_SNP	= 2,
+	HV_ISOLATION_TYPE_TDX	= 3
 };
 
 /* Hyper-V specific model specific registers (MSRs) */
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index fc09b6739922..9d593ab2be26 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -14,6 +14,7 @@
 union hv_ghcb;
 
 DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
+DECLARE_STATIC_KEY_FALSE(isolation_type_tdx);
 
 typedef int (*hyperv_fill_flush_list_func)(
 		struct hv_guest_mapping_flush_list *flush,
@@ -32,6 +33,8 @@ extern u64 hv_current_partition_id;
 
 extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
+extern bool hv_isolation_type_tdx(void);
+
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..9ad0b0abf0e0 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -338,9 +338,23 @@ static void __init ms_hyperv_init_platform(void)
 #endif
 		}
 		/* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
-		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
+		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) ||
+		    IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) {
+
+			switch (hv_get_isolation_type()) {
+			case HV_ISOLATION_TYPE_VBS:
+			case HV_ISOLATION_TYPE_SNP:
 				cc_set_vendor(CC_VENDOR_HYPERV);
+				break;
+
+			case HV_ISOLATION_TYPE_TDX:
+				static_branch_enable(&isolation_type_tdx);
+				break;
+
+			default:
+				WARN_ON(1);
+				break;
+			}
 		}
 	}
 
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index ae68298c0dca..a9a03ab04b97 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -268,6 +268,12 @@ bool __weak hv_isolation_type_snp(void)
 }
 EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
 
+bool __weak hv_isolation_type_tdx(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
+
 void __weak hv_setup_vmbus_handler(void (*handler)(void))
 {
 }
-- 
2.25.1