Switch build system to accompanied kernel headers

This helps reducing our build-time checks for feature support in the
available Linux kernel headers. And it helps users that do not have
sufficiently recent headers installed on their build machine.

Consequently, the patch removes and build-time checks for kvm and vhost
in configure, the --kerneldir switch, and KVM_CFLAGS. Kernel headers are
supposed to be provided by QEMU only.

s390 needs some extra love as it carries redefinitions from kernel
headers.

CC: Alexander Graf <agraf@suse.de>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/configure b/configure
index 44c092a..8df6485 100755
--- a/configure
+++ b/configure
@@ -113,8 +113,7 @@
 curses=""
 docs=""
 fdt=""
-kvm=""
-kvm_para=""
+kvm="yes"
 nptl=""
 sdl=""
 vnc="yes"
@@ -130,7 +129,7 @@
 xen_ctrl_version=""
 linux_aio=""
 attr=""
-vhost_net=""
+vhost_net="yes"
 xfs=""
 
 gprof="no"
@@ -166,7 +165,6 @@
 uname_release=""
 io_thread="no"
 mixemu="no"
-kerneldir=""
 aix="no"
 blobs="yes"
 pkgversion=""
@@ -715,8 +713,6 @@
   ;;
   --disable-blobs) blobs="no"
   ;;
-  --kerneldir=*) kerneldir="$optarg"
-  ;;
   --with-pkgversion=*) pkgversion=" ($optarg)"
   ;;
   --disable-docs) docs="no"
@@ -1005,7 +1001,6 @@
 echo "  --enable-attr            enable attr and xattr support"
 echo "  --enable-io-thread       enable IO thread"
 echo "  --disable-blobs          disable installing provided firmware blobs"
-echo "  --kerneldir=PATH         look for kernel includes in PATH"
 echo "  --enable-docs            enable documentation build"
 echo "  --disable-docs           disable documentation build"
 echo "  --disable-vhost-net      disable vhost-net acceleration support"
@@ -1779,124 +1774,6 @@
 fi
 
 ##########################################
-# kvm probe
-if test "$kvm" != "no" ; then
-    cat > $TMPC <<EOF
-#include <linux/kvm.h>
-#if !defined(KVM_API_VERSION) || KVM_API_VERSION < 12 || KVM_API_VERSION > 12
-#error Invalid KVM version
-#endif
-EOF
-    must_have_caps="KVM_CAP_USER_MEMORY \
-                    KVM_CAP_DESTROY_MEMORY_REGION_WORKS \
-                    KVM_CAP_COALESCED_MMIO \
-                    KVM_CAP_SYNC_MMU \
-                   "
-    if test \( "$cpu" = "i386" -o "$cpu" = "x86_64" \) ; then
-      must_have_caps="$caps \
-                      KVM_CAP_SET_TSS_ADDR \
-                      KVM_CAP_EXT_CPUID \
-                      KVM_CAP_CLOCKSOURCE \
-                      KVM_CAP_NOP_IO_DELAY \
-                      KVM_CAP_PV_MMU \
-                      KVM_CAP_MP_STATE \
-                      KVM_CAP_USER_NMI \
-                     "
-    fi
-    for c in $must_have_caps ; do
-      cat >> $TMPC <<EOF
-#if !defined($c)
-#error Missing KVM capability $c
-#endif
-EOF
-    done
-    cat >> $TMPC <<EOF
-int main(void) { return 0; }
-EOF
-  if test "$kerneldir" != "" ; then
-      kvm_cflags=-I"$kerneldir"/include
-      if test \( "$cpu" = "i386" -o "$cpu" = "x86_64" \) \
-         -a -d "$kerneldir/arch/x86/include" ; then
-            kvm_cflags="$kvm_cflags -I$kerneldir/arch/x86/include"
-	elif test "$cpu" = "ppc" -a -d "$kerneldir/arch/powerpc/include" ; then
-	    kvm_cflags="$kvm_cflags -I$kerneldir/arch/powerpc/include"
-	elif test "$cpu" = "s390x" -a -d "$kerneldir/arch/s390/include" ; then
-	    kvm_cflags="$kvm_cflags -I$kerneldir/arch/s390/include"
-        elif test -d "$kerneldir/arch/$cpu/include" ; then
-            kvm_cflags="$kvm_cflags -I$kerneldir/arch/$cpu/include"
-      fi
-  else
-    kvm_cflags=`$pkg_config --cflags kvm-kmod 2>/dev/null`
-  fi
-  if compile_prog "$kvm_cflags" "" ; then
-    kvm=yes
-    cat > $TMPC <<EOF
-#include <linux/kvm_para.h>
-int main(void) { return 0; }
-EOF
-    if compile_prog "$kvm_cflags" "" ; then
-      kvm_para=yes
-    fi
-  else
-    if test "$kvm" = "yes" ; then
-      if has awk && has grep; then
-        kvmerr=`LANG=C $cc $QEMU_CFLAGS -o $TMPE $kvm_cflags $TMPC 2>&1 \
-	| grep "error: " \
-	| awk -F "error: " '{if (NR>1) printf(", "); printf("%s",$2);}'`
-        if test "$kvmerr" != "" ; then
-          echo -e "${kvmerr}\n\
-NOTE: To enable KVM support, update your kernel to 2.6.29+ or install \
-recent kvm-kmod from http://sourceforge.net/projects/kvm."
-        fi
-      fi
-      feature_not_found "kvm"
-    fi
-    kvm=no
-  fi
-fi
-
-##########################################
-# test for ppc kvm pvr setting
-
-if test "$kvm" = "yes" && test "$cpu" = "ppc" -o "$cpu" = "ppc64"; then
-            cat > $TMPC <<EOF
-    #include <asm/kvm.h>
-    int main(void) { struct kvm_sregs s; s.pvr = 0; return 0; }
-EOF
-    if compile_prog "$kvm_cflags" "" ; then
-        kvm_ppc_pvr=yes
-    else
-        kvm_ppc_pvr=no
-    fi
-fi
-
-##########################################
-# test for vhost net
-
-if test "$vhost_net" != "no"; then
-    if test "$kvm" != "no"; then
-            cat > $TMPC <<EOF
-    #include <linux/vhost.h>
-    int main(void) { return 0; }
-EOF
-            if compile_prog "$kvm_cflags" "" ; then
-                vhost_net=yes
-            else
-                if test "$vhost_net" = "yes" ; then
-                    feature_not_found "vhost-net"
-                fi
-                vhost_net=no
-            fi
-    else
-            if test "$vhost_net" = "yes" ; then
-                echo "NOTE: vhost-net feature requires KVM (--enable-kvm)."
-                feature_not_found "vhost-net"
-            fi
-            vhost_net=no
-    fi
-fi
-
-##########################################
 # pthread probe
 PTHREADLIBS_LIST="-lpthread -lpthreadGC2"
 
@@ -3346,16 +3223,11 @@
       \( "$target_arch2" = "x86_64" -a "$cpu" = "i386"   \) -o \
       \( "$target_arch2" = "i386"   -a "$cpu" = "x86_64" \) \) ; then
       echo "CONFIG_KVM=y" >> $config_target_mak
-      echo "KVM_CFLAGS=$kvm_cflags" >> $config_target_mak
-      if test "$kvm_para" = "yes"; then
-        echo "CONFIG_KVM_PARA=y" >> $config_target_mak
-      fi
+      echo "CONFIG_KVM_PARA=y" >> $config_target_mak
       if test $vhost_net = "yes" ; then
         echo "CONFIG_VHOST_NET=y" >> $config_target_mak
       fi
-      if test "$kvm_ppc_pvr" = "yes" ; then
-        echo "CONFIG_KVM_PPC_PVR=y" >> $config_target_mak
-      fi
+      echo "CONFIG_KVM_PPC_PVR=y" >> $config_target_mak
     fi
 esac
 if test "$target_bigendian" = "yes" ; then
@@ -3546,6 +3418,21 @@
   esac
 fi
 
+# use included Linux headers
+includes="-I\$(SRC_PATH)/linux-headers $includes"
+mkdir -p linux-headers
+case "$cpu" in
+i386|x86_64)
+  symlink $source_path/linux-headers/asm-x86 linux-headers/asm
+  ;;
+ppcemb|ppc|ppc64)
+  symlink $source_path/linux-headers/asm-x86 linux-headers/asm
+  ;;
+s390x)
+  symlink $source_path/linux-headers/asm-s390 linux-headers/asm
+  ;;
+esac
+
 echo "LDFLAGS+=$ldflags" >> $config_target_mak
 echo "QEMU_CFLAGS+=$cflags" >> $config_target_mak
 echo "QEMU_INCLUDES+=$includes" >> $config_target_mak