Register Intercept Exit

Context data for an Arm64 exit caused by an intercepted register access.

Syntax

//
// Context data for an exit caused by an intercepted register access
// (WHvMessageTypeRegisterIntercept)
//

//
// Define register intercept message structure.
//
typedef union WHV_REGISTER_ACCESS_INFO
{
    WHV_REGISTER_VALUE SourceValue;
    WHV_REGISTER_NAME DestinationRegister;
} WHV_REGISTER_ACCESS_INFO;

typedef struct WHV_REGISTER_CONTEXT
{
    WHV_INTERCEPT_MESSAGE_HEADER Header;
    struct
    {
        UINT8 IsMemoryOp:1;
        UINT8 Reserved:7;
    };
    UINT8 Reserved8;
    UINT16 Reserved16;
    WHV_REGISTER_NAME RegisterName;
    WHV_REGISTER_ACCESS_INFO AccessInfo;
} WHV_REGISTER_CONTEXT;

Remarks

Information about an exit caused by the virtual processor accessing an intercepted system register is provided in the WHV_REGISTER_CONTEXT structure. The exit is reported with the WHvMessageTypeRegisterIntercept exit reason.

The exit is generated when the guest writes one of the synthetic guest-crash registers — WHvRegisterGuestCrashP0 through WHvRegisterGuestCrashP4, or WHvRegisterGuestCrashCtl — which a guest can use to report a crash to the virtualization stack.

The Header member is a WHV_INTERCEPT_MESSAGE_HEADER, which reports the program counter (Pc) and saved processor state (Cpsr) at the time of the access, along with the access direction in WHV_INTERCEPT_MESSAGE_HEADER.InterceptAccessType (a WHV_MEMORY_ACCESS_TYPE value).

The RegisterName member is the WHV_REGISTER_NAME of the intercepted register. The AccessInfo member carries the value for a register write and identifies the target for a register read:

• AccessInfo.SourceValue is a WHV_REGISTER_VALUE that carries the value written for a register write.
• AccessInfo.DestinationRegister is a WHV_REGISTER_NAME that identifies the target register for a register read.

The IsMemoryOp bit indicates whether the intercepted access is a memory operation.

See also

• WHvRunVirtualProcessor
• Exit Contexts