TDCALL

                            SECURE ARBITRATION MODE (SEAM)
<b>TDCALL</b> — Call SEAM Module

Opcode	Instruction	Op/ En	64-bit Mode	Compat/ Leg Mode	Description
66 0F 01 CC	TDCALL	ZO	Valid	Valid	Call SEAM monitor from SEAM guest.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
ZO	N/A	N/A	N/A	N/A

Description

TDCALL is a privileged instruction that allows software running in SEAM non-root operation to call software running in SEAM root operation. The instruction can be executed only in SEAM non-root operation or VMX non-root operation.

In SEAM non-root operation or VMX non-root operation, execution causes a VM exit with exit reason 77 (TDCALL).

Operation

IF not in SEAM non-root operation and not in VMX non-root operation
    THEN #UD;
ELSIF CPL > 0
    THEN #GP(0);
    ELSE VM exit;
FI;

Flags Affected

None.

Protected Mode Exceptions

#UD If executed outside VMX non-root operation and outside SEAM non-root operation.

#GP(0) If the current privilege level is not 0.

Real-Address Mode Exceptions

#UD If executed outside VMX non-root operation and outside SEAM non-root operation.

Virtual-8086 Mode Exceptions

#UD If executed outside VMX non-root operation and outside SEAM non-root operation.

#GP(0) If executed in VMX non-root operation or in SEAM non-root operation.

Compatibility Mode Exceptions

Same as protected mode exceptions.

64-Bit Mode Exceptions

Same as protected mode exceptions.

Vol. 3C 35-9 INTEL® PROCESSOR TRACE

Table 36-51. Event Data Packet Definition (Contd.)

Packet Format	7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 0 0 1 1 2 Reserved Type[5:0] 3 Payload[7:0] 4 Payload[15:8] 5 Payload[23:16] 6 Payload[31:24] 7 Payload[39:32] 8 Payload[47:40] 9 Payload[55:48] 10 Payload[63:56]
																	7	6			5	4		3	2	1	0
																0	0	0			0	0		0	0	1	0
																1	0	1			0	1		0	0	1	1
																2	Reserved				Type[5:0]
																3	Payload[7:0]
																4	Payload[15:8]
																5	Payload[23:16]
																6	Payload[31:24]
																7	Payload[39:32]
																8	Payload[47:40]
																9	Payload[55:48]
																10	Payload[63:56]
Dependencies	IA32_RTIT_CTL.EventEn && TriggerEn && ContextEn					Generation Scenario			Page fault, including those injected on VM entry. VM exit, if “Suppress VMX packets on exit” VMCS exit control is 0.
Description	Provides additional data about the event that caused the following CFE. The Payload field is dictated by the Type. Type Payload '000000 Page Fault Linear Address, same as CR2 (PFA) '000001 VMX Exit Qualification (VMXQ) '000010 VMX Exit Reason (VMXR) '000011 - '111111 Reserved EVD packets are never generated in cases where a CFE is not.
																Type			Payload
																'000000			Page Fault Linear Address, same as CR2 (PFA)
																'000001			VMX Exit Qualification (VMXQ)
																'000010			VMX Exit Reason (VMXR)
																'000011 - '111111			Reserved
Application	EVD packets bind to the same IP (if any) as the subsequent CFE packet.

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Source: Intel® 64 and IA-32 Architectures Software Developer's Manual, Combined Volumes (Order Number 325462-091US, March 2026)
Generated: 7-6-2026