Commit 8387ce06 authored by Tianyu Lan's avatar Tianyu Lan Committed by Wei Liu
Browse files

x86/hyperv: Set Virtual Trust Level in VMBus init message 



SEV-SNP guests on Hyper-V can run at multiple Virtual Trust
Levels (VTL).  During boot, get the VTL at which we're running
using the GET_VP_REGISTERs hypercall, and save the value
for future use.  Then during VMBus initialization, set the VTL
with the saved value as required in the VMBus init message.

Reviewed-by: default avatarDexuan Cui <decui@microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarTianyu Lan <tiala@microsoft.com>
Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230818102919.1318039-3-ltykernel@gmail.com
parent d6e2d652

arch/x86/hyperv/hv_init.c

+34 −0
Original line number Diff line number Diff line
@@ -378,6 +378,36 @@ 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;

	struct hv_get_vp_registers_output *output;

	unsigned long flags;

	u64 ret;



	local_irq_save(flags);

	input = *this_cpu_ptr(hyperv_pcpu_input_arg);

	output = (struct hv_get_vp_registers_output *)input;



	memset(input, 0, struct_size(input, element, 1));

	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 (hv_result_success(ret)) {

		ret = output->as64.low & HV_X64_VTL_MASK;

	} else {

		pr_err("Failed to get VTL(%lld) and set VTL to zero by default.\n", ret);

		ret = 0;

	}



	local_irq_restore(flags);

	return ret;

}



/*

 * This function is to be invoked early in the boot sequence after the

 * hypervisor has been detected.
@@ -506,6 +536,10 @@ 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 */

	if (hv_isolation_type_en_snp())

		ms_hyperv.vtl = get_vtl();



	return;



clean_guest_os_id:

arch/x86/include/asm/hyperv-tlfs.h

+7 −0
Original line number Diff line number Diff line
@@ -301,6 +301,13 @@ enum hv_isolation_type { 
#define HV_X64_MSR_TIME_REF_COUNT	HV_REGISTER_TIME_REF_COUNT

#define HV_X64_MSR_REFERENCE_TSC	HV_REGISTER_REFERENCE_TSC



/*

 * Registers are only accessible via HVCALL_GET_VP_REGISTERS hvcall and

 * there is not associated MSR address.

 */

#define	HV_X64_REGISTER_VSM_VP_STATUS	0x000D0003

#define	HV_X64_VTL_MASK			GENMASK(3, 0)



/* Hyper-V memory host visibility */

enum hv_mem_host_visibility {

	VMBUS_PAGE_NOT_VISIBLE		= 0,

drivers/hv/connection.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

include/asm-generic/mshyperv.h

+1 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ struct ms_hyperv_info { 
		};

	};

	u64 shared_gpa_boundary;

	u8 vtl;

};

extern struct ms_hyperv_info ms_hyperv;

extern bool hv_nested;

include/linux/hyperv.h

+2 −2
Original line number Diff line number Diff line
@@ -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;