[RFC PATCH V3 03/16] x86/hyperv: Set Virtual Trust Level in vmbus init message

[Tianyu Lan <ltykernel@gmail.com>]

From: Tianyu Lan <tiala@microsoft.com>

sev-snp guest provides vtl(Virtual Trust Level) and
get it from hyperv hvcall via HVCALL_GET_VP_REGISTERS.
Set target vtl in the vmbus init message.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC v2:
       * Rename get_current_vtl() to get_vtl()
       * Fix some coding style issues
---
 arch/x86/hyperv/hv_init.c          | 37 ++++++++++++++++++++++++++++++
 arch/x86/include/asm/hyperv-tlfs.h |  4 ++++
 drivers/hv/connection.c            |  1 +
 include/asm-generic/mshyperv.h     |  2 ++
 include/linux/hyperv.h             |  4 ++--
 5 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 24154c1ee12b..9e9757049915 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -384,6 +384,40 @@ static void __init hv_get_partition_id(void)
 	local_irq_restore(flags);
 }
 
+static u8 __init get_vtl(void)
+{
+	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
+	struct hv_get_vp_registers_input *input = NULL;
+	struct hv_get_vp_registers_output *output = NULL;
+	u64 vtl = 0;
+	int ret;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	input = *(struct hv_get_vp_registers_input **)this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = (struct hv_get_vp_registers_output *)input;
+	if (!input || !output) {
+		local_irq_restore(flags);
+		goto done;
+	}
+
+	memset(input, 0, sizeof(*input) + sizeof(input->element[0]));
+	input->header.partitionid = HV_PARTITION_ID_SELF;
+	input->header.vpindex = HV_VP_INDEX_SELF;
+	input->header.inputvtl = 0;
+	input->element[0].name0 = HV_X64_REGISTER_VSM_VP_STATUS;
+
+	ret = hv_do_hypercall(control, input, output);
+	if (ret == 0)
+		vtl = output->as64.low & HV_X64_VTL_MASK;
+	else
+		pr_err("Hyper-V: failed to get VTL!");
+	local_irq_restore(flags);
+
+done:
+	return vtl;
+}
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -512,6 +546,9 @@ void __init hyperv_init(void)
 	/* Query the VMs extended capability once, so that it can be cached. */
 	hv_query_ext_cap(0);
 
+	/* Find the VTL */
+	ms_hyperv.vtl = get_vtl();
+
 	return;
 
 clean_guest_os_id:
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index db2202d985bd..6dcbb21aac2b 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -36,6 +36,10 @@
 #define HYPERV_CPUID_MIN			0x40000005
 #define HYPERV_CPUID_MAX			0x4000ffff
 
+/* Support for HVCALL_GET_VP_REGISTERS hvcall */
+#define	HV_X64_REGISTER_VSM_VP_STATUS	0x000D0003
+#define HV_X64_VTL_MASK			GENMASK(3, 0)
+
 /*
  * Group D Features.  The bit assignments are custom to each architecture.
  * On x86/x64 these are HYPERV_CPUID_FEATURES.EDX bits.
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index f670cfd2e056..e4c39f4016ad 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -98,6 +98,7 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
 	 */
 	if (version >= VERSION_WIN10_V5) {
 		msg->msg_sint = VMBUS_MESSAGE_SINT;
+		msg->msg_vtl = ms_hyperv.vtl;
 		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
 	} else {
 		msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index f2c0856f1797..44e56777fea7 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -48,6 +48,7 @@ struct ms_hyperv_info {
 		};
 	};
 	u64 shared_gpa_boundary;
+	u8 vtl;
 };
 extern struct ms_hyperv_info ms_hyperv;
 
@@ -57,6 +58,7 @@ extern void * __percpu *hyperv_pcpu_output_arg;
 extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
 extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
 extern bool hv_isolation_type_snp(void);
+extern bool hv_isolation_type_en_snp(void);
 
 /* Helper functions that provide a consistent pattern for checking Hyper-V hypercall status. */
 static inline int hv_result(u64 status)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 85f7c5a63aa6..65121b21b0af 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -665,8 +665,8 @@ struct vmbus_channel_initiate_contact {
 		u64 interrupt_page;
 		struct {
 			u8	msg_sint;
-			u8	padding1[3];
-			u32	padding2;
+			u8	msg_vtl;
+			u8	reserved[6];
 		};
 	};
 	u64 monitor_page1;
-- 
2.25.1