Re: [PATCH v2] x86: reduce dependencies on x86_emulate/x86_emulate.h

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 12/08/2026 2:24 pm, Jan Beulich wrote:
> Split out struct x86_event to an entirely separate header, and move a few
> other items describing the architecture to a new x86-types.h. With a few
> forward decls of structures and with a fair number of new #include-s in
> .c files, the inclusion of x86_emulate.h (and hence
> x86_emulate/x86_emulate.h) can be dropped from all header files except
> hvm/emulate.h; it needs additionally adding to hvm/ioreq.h though.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

> --- /dev/null
> +++ b/xen/arch/x86/include/asm/x86-event.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * x86-event.h
> + *
> + * Helper definitions for event handling, which aren't prescribed by the
> + * architecture itself.
> + */
> +
> +#ifndef X86_X86_EVENT_H
> +#define X86_X86_EVENT_H
> +
> +#ifdef __XEN__
> +# include <xen/types.h>
> +#else
> +# include <stdint.h>
> +#endif
> +
> +#define X86_EVENT_NO_EC (-1)        /* No error code. */
> +
> +struct x86_event {
> +    int16_t       vector;
> +    uint8_t       type;         /* X86_ET_* */
> +    uint8_t       insn_len;     /* Instruction length */
> +    int32_t       error_code;   /* X86_EVENT_NO_EC if n/a */
> +    union {
> +        unsigned long cr2;         /* #PF */
> +        unsigned long pending_dbg; /* #DB (new DR6 bits, positive polarity) 
> */

With the advent of FRED, this probably wants to become event_data (or
just data) and drop the union.

It's also the XFD_ERR mask for #NM, and the NMI Source Bitmap (on
capable hardware), and I think we're better off pointing to the FRED
spec than keeping an out-of-date list of what's in it.

~Andrew