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@suse.com>
---
The use in drivers/vpci/msix.c is certainly somewhat bogus, but as long as
X86EMUL_OKAY etc are used directly there, that's the way to go. Like done
for IOREQ, some abstraction will be needed here if this file was to be
re-used by non-x86.
---
v2: Minor comment adjustment ahead of enum x86_segment. Also cover
    hvm/svm/vmcb.h.

--- a/tools/tests/x86_emulator/Makefile
+++ b/tools/tests/x86_emulator/Makefile
@@ -305,7 +305,7 @@ $(call cc-option-add,HOSTCFLAGS-x86_64,H
 HOSTCFLAGS += $(CFLAGS_xeninclude) -I. $(HOSTCFLAGS-$(XEN_COMPILE_ARCH))
 
 x86.h := $(addprefix $(XEN_ROOT)/tools/include/xen/asm/,\
-                     x86-vendors.h x86-defns.h msr-index.h) \
+                     x86-vendors.h x86-defns.h x86-types.h x86-event.h msr-index.h) \
          $(addprefix $(XEN_ROOT)/tools/include/xen/lib/x86/, \
                      cpu-policy.h cpuid-autogen.h)
 x86_emulate.h := x86-emulate.h x86_emulate/x86_emulate.h x86_emulate/private.h $(x86.h)
--- a/tools/tests/x86_emulator/x86-emulate.h
+++ b/tools/tests/x86_emulator/x86-emulate.h
@@ -38,6 +38,8 @@
 
 #include <xen/asm/msr-index.h>
 #include <xen/asm/x86-defns.h>
+#include <xen/asm/x86-event.h>
+#include <xen/asm/x86-types.h>
 #include <xen/asm/x86-vendors.h>
 
 #include <xen-tools/common-macros.h>
--- a/xen/arch/x86/emul-i8254.c
+++ b/xen/arch/x86/emul-i8254.c
@@ -37,6 +37,7 @@
 #include <asm/hvm/save.h>
 #include <asm/hvm/vpt.h>
 #include <asm/time.h>
+#include <asm/x86_emulate.h>
 
 #define domain_vpit(x) (&(x)->arch.vpit)
 #define vcpu_vpit(x)   (domain_vpit((x)->domain))
--- a/xen/arch/x86/hvm/hpet.c
+++ b/xen/arch/x86/hvm/hpet.c
@@ -11,6 +11,8 @@
 #include <asm/current.h>
 #include <asm/hpet.h>
 #include <asm/mc146818rtc.h>
+#include <asm/x86_emulate.h>
+
 #include <xen/sched.h>
 #include <xen/event.h>
 #include <xen/trace.h>
--- a/xen/arch/x86/hvm/mmio.c
+++ b/xen/arch/x86/hvm/mmio.c
@@ -9,6 +9,7 @@
 #include <xen/mm.h>
 
 #include <asm/p2m.h>
+#include <asm/x86_emulate.h>
 
 static int cf_check subpage_mmio_accept(struct vcpu *v, unsigned long addr)
 {
--- a/xen/arch/x86/hvm/pmtimer.c
+++ b/xen/arch/x86/hvm/pmtimer.c
@@ -11,6 +11,8 @@
 #include <asm/hvm/io.h>
 #include <asm/hvm/save.h>
 #include <asm/acpi.h> /* for hvm_acpi_power_button prototype */
+#include <asm/x86_emulate.h>
+
 #include <public/hvm/params.h>
 
 /* Slightly more readable port I/O addresses for the registers we intercept */
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -23,12 +23,15 @@
  */
 
 #include <xen/sched.h>
-#include <asm/mc146818rtc.h>
-#include <asm/hvm/vpt.h>
+#include <xen/trace.h>
+
 #include <asm/hvm/io.h>
 #include <asm/hvm/save.h>
+#include <asm/hvm/vpt.h>
 #include <asm/iocap.h>
-#include <xen/trace.h>
+#include <asm/mc146818rtc.h>
+#include <asm/x86_emulate.h>
+
 #include <public/hvm/params.h>
 
 #define USEC_PER_SEC    1000000UL
--- a/xen/arch/x86/hvm/stdvga.c
+++ b/xen/arch/x86/hvm/stdvga.c
@@ -34,6 +34,8 @@
 #include <xen/numa.h>
 #include <xen/paging.h>
 
+#include <asm/x86_emulate.h>
+
 #define VGA_MEM_BASE 0xa0000
 #define VGA_MEM_SIZE 0x20000
 
--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -11,6 +11,7 @@
 #include <asm/paging.h> /* paging_mode_hap */
 #include <asm/event.h> /* for local_event_delivery_(en|dis)able */
 #include <asm/p2m.h> /* p2m_get_pagetable, p2m_get_nestedp2m */
+#include <asm/x86_emulate.h>
 
 #include "nestedhvm.h"
 #include "svm.h"
--- a/xen/arch/x86/hvm/svm/vmcb.h
+++ b/xen/arch/x86/hvm/svm/vmcb.h
@@ -4,7 +4,7 @@
 
 #include <xen/types.h>
 
-#include <asm/x86_emulate.h>
+#include <asm/x86-types.h>
 
 struct vcpu;
 
--- a/xen/arch/x86/hvm/vioapic.c
+++ b/xen/arch/x86/hvm/vioapic.c
@@ -38,6 +38,7 @@
 #include <asm/current.h>
 #include <asm/event.h>
 #include <asm/io_apic.h>
+#include <asm/x86_emulate.h>
 
 /* HACK: Route IRQ0 only to VCPU0 to prevent time jumps. */
 #define IRQ0_SPECIAL_ROUTING 1
--- a/xen/arch/x86/hvm/viridian/private.h
+++ b/xen/arch/x86/hvm/viridian/private.h
@@ -5,6 +5,8 @@
 
 #include <asm/hvm/save.h>
 #include <asm/hvm/viridian.h>
+#include <asm/x86_emulate.h>
+
 #include <public/hvm/params.h>
 
 int viridian_synic_wrmsr(struct vcpu *v, uint32_t idx, uint64_t val);
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -18,6 +18,7 @@
 #include <asm/msr.h>
 #include <asm/mtrr.h>
 #include <asm/p2m.h>
+#include <asm/x86_emulate.h>
 
 static DEFINE_PER_CPU(u64 *, vvmcs_buf);
 
--- a/xen/arch/x86/hvm/vpic.c
+++ b/xen/arch/x86/hvm/vpic.c
@@ -33,6 +33,7 @@
 #include <asm/hvm/hvm.h>
 #include <asm/hvm/io.h>
 #include <asm/hvm/save.h>
+#include <asm/x86_emulate.h>
 
 #define vpic_domain(v) (container_of((v), struct domain, \
                                      arch.hvm.vpic[!(v)->is_master]))
--- a/xen/arch/x86/include/asm/domain.h
+++ b/xen/arch/x86/include/asm/domain.h
@@ -8,7 +8,8 @@
 #include <asm/e820.h>
 #include <asm/mce.h>
 #include <asm/vpmu.h>
-#include <asm/x86_emulate.h>
+#include <asm/x86-types.h>
+
 #include <public/vcpu.h>
 #include <public/hvm/hvm_info_table.h>
 
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -16,11 +16,13 @@
 #include <asm/current.h>
 #include <asm/hvm/asid.h>
 #include <asm/msr-index.h>
-#include <asm/x86_emulate.h>
+#include <asm/x86-event.h>
+#include <asm/x86-types.h>
 
 struct pirq; /* needed by pi_update_irte */
 struct hvm_hw_cpu;
 struct xen_domctl_createdomain;
+struct x86_event;
 
 #ifdef CONFIG_HVM_FEP
 /* Permit use of the Forced Emulation Prefix in HVM guests */
--- a/xen/arch/x86/include/asm/hvm/ioreq.h
+++ b/xen/arch/x86/include/asm/hvm/ioreq.h
@@ -8,6 +8,8 @@
 #ifndef __ASM_X86_HVM_IOREQ_H__
 #define __ASM_X86_HVM_IOREQ_H__
 
+#include <asm/x86_emulate.h>
+
 /* This correlation must not be altered */
 #define IOREQ_STATUS_HANDLED     X86EMUL_OKAY
 #define IOREQ_STATUS_UNHANDLED   X86EMUL_UNHANDLEABLE
--- a/xen/arch/x86/include/asm/hvm/vcpu.h
+++ b/xen/arch/x86/include/asm/hvm/vcpu.h
@@ -14,6 +14,8 @@
 #include <asm/hvm/vmx/vvmx.h>
 #include <asm/hvm/svm-types.h>
 #include <asm/mtrr.h>
+#include <asm/x86-event.h>
+
 #include <public/hvm/ioreq.h>
 
 struct hvm_vcpu_asid {
--- a/xen/arch/x86/include/asm/hvm/vmx/vmcs.h
+++ b/xen/arch/x86/include/asm/hvm/vmx/vmcs.h
@@ -9,6 +9,8 @@
 
 #include <xen/mm.h>
 
+#include <asm/x86-types.h>
+
 extern void vmcs_dump_vcpu(struct vcpu *v);
 extern int vmx_vmcs_init(void);
 int cf_check vmx_cpu_up_prepare(unsigned int cpu);
--- a/xen/arch/x86/include/asm/mce.h
+++ b/xen/arch/x86/include/asm/mce.h
@@ -35,6 +35,7 @@ struct vmce {
 
 struct domain;
 struct vcpu;
+struct hvm_vmce_vcpu;
 
 /* Guest vMCE MSRs virtualization */
 extern void vmce_init_vcpu(struct vcpu *v);
--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -8,7 +8,6 @@
 #include <asm/io.h>
 #include <asm/page.h>
 #include <asm/uaccess.h>
-#include <asm/x86_emulate.h>
 
 /*
  * Per-page-frame information.
--- /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) */
+    };
+};
+
+#endif /* X86_X86_EVENT_H */
--- /dev/null
+++ b/xen/arch/x86/include/asm/x86-types.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * x86-types.h
+ *
+ * Type definitions and basic helpers which are more or less directly
+ * describing aspects of the architecture.
+ */
+
+#ifndef X86_X86_TYPES_H
+#define X86_X86_TYPES_H
+
+#ifdef __XEN__
+# include <xen/types.h>
+#else
+# include <stdint.h>
+#endif
+
+/*
+ * Comprehensive enumeration of x86 segment registers.  Various bits of code
+ * rely on this order (general purpose before system, tr at the beginning of
+ * system).
+ */
+enum x86_segment {
+    /* General purpose.  Matches the SReg3 encoding in opcode/ModRM bytes. */
+    x86_seg_es,
+    x86_seg_cs,
+    x86_seg_ss,
+    x86_seg_ds,
+    x86_seg_fs,
+    x86_seg_gs,
+    /* System: Valid to use for implicit table references. */
+    x86_seg_tr,
+    x86_seg_ldtr,
+    x86_seg_gdtr,
+    x86_seg_idtr,
+    /* No Segment: For (system/normal) accesses which are already linear. */
+    x86_seg_sys,
+    x86_seg_none
+};
+
+static inline bool is_x86_user_segment(enum x86_segment seg)
+{
+    unsigned int idx = seg;
+
+    return idx <= x86_seg_gs;
+}
+static inline bool is_x86_system_segment(enum x86_segment seg)
+{
+    return seg >= x86_seg_tr && seg < x86_seg_none;
+}
+
+/*
+ * Full state of a segment register (visible and hidden portions).
+ * Chosen to match the format of an AMD SVM VMCB.
+ */
+struct segment_register {
+    uint16_t   sel;
+    union {
+        uint16_t attr;
+        struct {
+            uint16_t type:4;
+            uint16_t s:   1;
+            uint16_t dpl: 2;
+            uint16_t p:   1;
+            uint16_t avl: 1;
+            uint16_t l:   1;
+            uint16_t db:  1;
+            uint16_t g:   1;
+            uint16_t pad: 4;
+        };
+    };
+    uint32_t   limit;
+    uint64_t   base;
+};
+
+#endif	/* X86_X86_TYPES_H */
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -22,6 +22,7 @@
 #include <asm/p2m.h>
 #include <asm/pv/domain.h>
 #include <asm/setup.h>
+#include <asm/x86_emulate.h>
 #include <asm/xstate.h>
 
 #include <public/hvm/params.h>
--- a/xen/arch/x86/pv/misc-hypercalls.c
+++ b/xen/arch/x86/pv/misc-hypercalls.c
@@ -12,6 +12,7 @@
 #include <asm/debugreg.h>
 #include <asm/fsgsbase.h>
 #include <asm/traps.h>
+#include <asm/x86_emulate.h>
 
 long do_set_debugreg(int reg, unsigned long value)
 {
--- a/xen/arch/x86/x86_emulate/x86_emulate.h
+++ b/xen/arch/x86/x86_emulate/x86_emulate.h
@@ -13,6 +13,11 @@
 
 #include <xen/lib/x86/cpu-policy.h>
 
+#ifdef __XEN__
+# include <asm/x86-event.h>
+# include <asm/x86-types.h>
+#endif
+
 #define MAX_INST_LEN 15
 
 #if defined(__i386__)
@@ -25,77 +30,6 @@
 
 struct x86_emulate_ctxt;
 
-/*
- * Comprehensive enumeration of x86 segment registers.  Various bits of code
- * rely on this order (general purpose before system, tr at the beginning of
- * system).
- */
-enum x86_segment {
-    /* General purpose.  Matches the SReg3 encoding in opcode/ModRM bytes. */
-    x86_seg_es,
-    x86_seg_cs,
-    x86_seg_ss,
-    x86_seg_ds,
-    x86_seg_fs,
-    x86_seg_gs,
-    /* System: Valid to use for implicit table references. */
-    x86_seg_tr,
-    x86_seg_ldtr,
-    x86_seg_gdtr,
-    x86_seg_idtr,
-    /* No Segment: For (system/normal) accesses which are already linear. */
-    x86_seg_sys,
-    x86_seg_none
-};
-
-static inline bool is_x86_user_segment(enum x86_segment seg)
-{
-    unsigned int idx = seg;
-
-    return idx <= x86_seg_gs;
-}
-static inline bool is_x86_system_segment(enum x86_segment seg)
-{
-    return seg >= x86_seg_tr && seg < x86_seg_none;
-}
-
-#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) */
-    };
-};
-
-/*
- * Full state of a segment register (visible and hidden portions).
- * Chosen to match the format of an AMD SVM VMCB.
- */
-struct segment_register {
-    uint16_t   sel;
-    union {
-        uint16_t attr;
-        struct {
-            uint16_t type:4;
-            uint16_t s:   1;
-            uint16_t dpl: 2;
-            uint16_t p:   1;
-            uint16_t avl: 1;
-            uint16_t l:   1;
-            uint16_t db:  1;
-            uint16_t g:   1;
-            uint16_t pad: 4;
-        };
-    };
-    uint32_t   limit;
-    uint64_t   base;
-};
-
 struct x86_emul_fpu_aux {
     unsigned long ip, dp;
     uint16_t cs, ds;
--- a/xen/drivers/vpci/msix.c
+++ b/xen/drivers/vpci/msix.c
@@ -25,6 +25,7 @@
 
 #include <asm/msi.h>
 #include <asm/p2m.h>
+#include <asm/x86_emulate.h>
 
 #define VMSIX_ADDR_IN_RANGE(addr, vpci, nr)                               \
     ((addr) >= vmsix_table_addr(vpci, nr) &&                              \

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@suse.com>

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

> --- /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

On 12.08.2026 15:39, Andrew Cooper wrote:
> 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@suse.com>
> 
> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

Thanks.

>> --- /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.

Yes, perhaps that's going to be better.

Jan