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HvCallSetVpRegisters

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The HvCallSetVpRegisters hypercall writes the state of a virtual processor.

Interface

HV_STATUS
HvCallSetVpRegisters(
   _In_ HV_PARTITION_ID PartitionId,
   _In_ HV_VP_INDEX VpIndex,
   _In_ HV_INPUT_VTL InputVtl,
   _Inout_ PUINT32 RegisterCount,
   _In_reads(RegisterCount) PCHV_REGISTER_NAME RegisterNameList,
   _In_reads(RegisterCount) PCHV_REGISTER_VALUE RegisterValueList
   );

The state is written as a series of register values, each corresponding to a register name provided as input.

Minimal error checking is performed when a register value is modified. In particular, the hypervisor will validate that reserved bits of a register are set to zero, bits that are architecturally defined as always containing a zero or a one are set appropriately, and specified bits beyond the architectural size of the register are zeroed.

This call cannot be used to modify the value of a read-only register.

Side-effects of modifying a register are not performed. This includes generation of exceptions, pipeline synchronizations, TLB flushes, and so on.

Restrictions

  • The caller must either be the parent of the partition specified by PartitionId, or the partition specified must be “self” and the partition must have the AccessVpRegisters privilege.

Call Code

0x0051 (Rep)

Input Parameters

Name Offset Size Information Provided
PartitionId 0 8 Specifies the partition Id.
VpIndex 8 4 Specifies the index of the virtual processor.
TargetVtl 12 1 specifies the target VTL.
RsvdZ 13 3

Input List Element

Name Offset Size Information Provided
RegisterName 0 4 Specifies the name of a register to be modified.
RsvdZ 4 12
RegisterValue 16 16 Specifies the new value for the specified register.

See also

HV_REGISTER_NAME

HV_REGISTER_VALUE