[v2,7/7] x86: only generate compat headers actually needed

Commit Message

Jan Beulich July 1, 2020, 10:28 a.m. UTC

As was already the case for XSM/Flask, avoid generating compat headers
when they're not going to be needed. To address resulting build issues
- move compat/hvm/dm_op.h inclusion to the only source file needing it,
- add a little bit of #ifdef-ary.

Signed-off-by: Jan Beulich <[e-mail]>
---
Alternatively we could consistently drop conditionals (except for per-
arch cases perhaps).

Comments

Roger Pau Monné July 14, 2020, 3:03 p.m. UTC | #1

On Wed, Jul 01, 2020 at 12:28:27PM +0200, Jan Beulich wrote:
> As was already the case for XSM/Flask, avoid generating compat headers
> when they're not going to be needed. To address resulting build issues
> - move compat/hvm/dm_op.h inclusion to the only source file needing it,
> - add a little bit of #ifdef-ary.
> 
> Signed-off-by: Jan Beulich <[e-mail]>

Reviewed-by: Roger Pau Monné <[e-mail]>

TBH I wouldn't mind generating the compat headers even when not
actually used by the build, sometimes is useful to have them for
review context without having to play with the build options.

Thanks.

Jan Beulich July 15, 2020, 6:47 a.m. UTC | #2

On 14.07.2020 17:03, Roger Pau Monné wrote:
> On Wed, Jul 01, 2020 at 12:28:27PM +0200, Jan Beulich wrote:
>> As was already the case for XSM/Flask, avoid generating compat headers
>> when they're not going to be needed. To address resulting build issues
>> - move compat/hvm/dm_op.h inclusion to the only source file needing it,
>> - add a little bit of #ifdef-ary.
>>
>> Signed-off-by: Jan Beulich <[e-mail]>
> 
> Reviewed-by: Roger Pau Monné <[e-mail]>

Thanks.

> TBH I wouldn't mind generating the compat headers even when not
> actually used by the build, sometimes is useful to have them for
> review context without having to play with the build options.

Right, that's what the post-commit-message remark says. The main
goal is to be consistent in what we do. The primary reason for
me to have chosen this route is that the compat header generation
isn't really quick, compared to the rest of the build process. It
is so slow that commit 7e9009891688 ("include: parallelize
compat/xlat.h generation") was a significant (i.e. very
noticeable) win.

Jan

Patch

--- a/xen/arch/x86/hvm/dm.c
+++ b/xen/arch/x86/hvm/dm.c
@@ -717,6 +717,8 @@  static int dm_op(const struct dmop_args
     return rc;
 }
 
+#include <compat/hvm/dm_op.h>
+
 CHECK_dm_op_create_ioreq_server;
 CHECK_dm_op_get_ioreq_server_info;
 CHECK_dm_op_ioreq_server_range;
--- a/xen/common/compat/domain.c
+++ b/xen/common/compat/domain.c
@@ -11,7 +11,6 @@  EMIT_FILE;
 #include <xen/guest_access.h>
 #include <xen/hypercall.h>
 #include <compat/vcpu.h>
-#include <compat/hvm/hvm_vcpu.h>
 
 #define xen_vcpu_set_periodic_timer vcpu_set_periodic_timer
 CHECK_vcpu_set_periodic_timer;
@@ -25,6 +24,10 @@  CHECK_SIZE_(struct, vcpu_info);
 CHECK_vcpu_register_vcpu_info;
 #undef xen_vcpu_register_vcpu_info
 
+#ifdef CONFIG_HVM
+
+#include <compat/hvm/hvm_vcpu.h>
+
 #define xen_vcpu_hvm_context vcpu_hvm_context
 #define xen_vcpu_hvm_x86_32 vcpu_hvm_x86_32
 #define xen_vcpu_hvm_x86_64 vcpu_hvm_x86_64
@@ -33,6 +36,8 @@  CHECK_vcpu_hvm_context;
 #undef xen_vcpu_hvm_x86_32
 #undef xen_vcpu_hvm_context
 
+#endif
+
 int compat_vcpu_op(int cmd, unsigned int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     struct domain *d = current->domain;
@@ -49,6 +54,7 @@  int compat_vcpu_op(int cmd, unsigned int
         if ( v->vcpu_info == &dummy_vcpu_info )
             return -EINVAL;
 
+#ifdef CONFIG_HVM
         if ( is_hvm_vcpu(v) )
         {
             struct vcpu_hvm_context ctxt;
@@ -61,6 +67,7 @@  int compat_vcpu_op(int cmd, unsigned int
             domain_unlock(d);
         }
         else
+#endif
         {
             struct compat_vcpu_guest_context *ctxt;
 
--- a/xen/include/Makefile
+++ b/xen/include/Makefile
@@ -3,32 +3,34 @@  ifneq ($(CONFIG_COMPAT),)
 compat-arch-$(CONFIG_X86) := x86_32
 
 headers-y := \
-    compat/argo.h \
-    compat/callback.h \
+    compat/arch-$(compat-arch-y).h \
     compat/elfnote.h \
     compat/event_channel.h \
     compat/features.h \
-    compat/grant_table.h \
-    compat/hypfs.h \
-    compat/kexec.h \
     compat/memory.h \
     compat/nmi.h \
     compat/physdev.h \
     compat/platform.h \
+    compat/pmu.h \
     compat/sched.h \
-    compat/trace.h \
     compat/vcpu.h \
     compat/version.h \
     compat/xen.h \
-    compat/xenoprof.h
+    compat/xlat.h
 headers-$(CONFIG_X86)     += compat/arch-x86/pmu.h
 headers-$(CONFIG_X86)     += compat/arch-x86/xen-mca.h
 headers-$(CONFIG_X86)     += compat/arch-x86/xen.h
 headers-$(CONFIG_X86)     += compat/arch-x86/xen-$(compat-arch-y).h
-headers-$(CONFIG_X86)     += compat/hvm/dm_op.h
-headers-$(CONFIG_X86)     += compat/hvm/hvm_op.h
-headers-$(CONFIG_X86)     += compat/hvm/hvm_vcpu.h
-headers-y                 += compat/arch-$(compat-arch-y).h compat/pmu.h compat/xlat.h
+headers-$(CONFIG_ARGO)    += compat/argo.h
+headers-$(CONFIG_PV)      += compat/callback.h
+headers-$(CONFIG_GRANT_TABLE) += compat/grant_table.h
+headers-$(CONFIG_HVM)     += compat/hvm/dm_op.h
+headers-$(CONFIG_HVM)     += compat/hvm/hvm_op.h
+headers-$(CONFIG_HVM)     += compat/hvm/hvm_vcpu.h
+headers-$(CONFIG_HYPFS)   += compat/hypfs.h
+headers-$(CONFIG_KEXEC)   += compat/kexec.h
+headers-$(CONFIG_TRACEBUFFER) += compat/trace.h
+headers-$(CONFIG_XENOPROF) += compat/xenoprof.h
 headers-$(CONFIG_XSM_FLASK) += compat/xsm/flask_op.h
 
 cppflags-y                := -include public/xen-compat.h -DXEN_GENERATING_COMPAT_HEADERS
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -216,8 +216,6 @@  extern long compat_argo_op(
     unsigned long arg4);
 #endif
 
-#include <compat/hvm/dm_op.h>
-
 extern int
 compat_dm_op(
     domid_t domid,