vhost: restrict Linux dependency to kernel vhost

vhost-user does not depend on Linux; it can run on any POSIX system.  Restrict
vhost-kernel to Linux in hw/virtio/vhost-backend.c, everything else can be
compiled on all POSIX systems.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1543851204-41186-4-git-send-email-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1550165756-21617-4-git-send-email-pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

backends/Makefile.objs

@@ -9,10 +9,9 @@ common-obj-$(CONFIG_POSIX) += hostmem-file.o
 common-obj-y += cryptodev.o
 common-obj-y += cryptodev-builtin.o
 
-ifeq ($(CONFIG_VIRTIO),y)
+ifeq ($(CONFIG_VIRTIO_CRYPTO),y)
 common-obj-y += cryptodev-vhost.o
-common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += \
-    cryptodev-vhost-user.o
+common-obj-$(CONFIG_VHOST_CRYPTO) += cryptodev-vhost-user.o
 endif
 
 common-obj-$(CONFIG_LINUX) += hostmem-memfd.o

default-configs/virtio.mak

@@ -1,5 +1,5 @@
-CONFIG_VHOST_USER_SCSI=$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX))
-CONFIG_VHOST_USER_BLK=$(call land,$(CONFIG_VHOST_USER),$(CONFIG_LINUX))
+CONFIG_VHOST_USER_SCSI=$(CONFIG_VHOST_USER)
+CONFIG_VHOST_USER_BLK=$(CONFIG_VHOST_USER)
 CONFIG_VIRTIO=y
 CONFIG_VIRTIO_9P=$(CONFIG_VIRTFS)
 CONFIG_VIRTIO_BALLOON=y

hw/net/vhost_net.c

@@ -18,14 +18,13 @@
 #include "net/tap.h"
 #include "net/vhost-user.h"
 
+#include "standard-headers/linux/vhost_types.h"
 #include "hw/virtio/virtio-net.h"
 #include "net/vhost_net.h"
 #include "qemu/error-report.h"
 
 
-#include <linux/vhost.h>
 #include <sys/socket.h>
-#include <linux/kvm.h>
 #include <netpacket/packet.h>
 #include <net/ethernet.h>
 #include <net/if.h>

hw/virtio/Makefile.objs

@@ -2,15 +2,18 @@ ifeq ($(CONFIG_VIRTIO),y)
 common-obj-y += virtio-bus.o
 obj-y += virtio.o
 
+obj-$(call lor,$(CONFIG_VHOST_USER),$(CONFIG_LINUX)) += vhost.o vhost-backend.o
+common-obj-$(call lnot,$(call lor,$(CONFIG_VHOST_USER),$(CONFIG_LINUX))) += vhost-stub.o
+obj-$(CONFIG_VHOST_USER) += vhost-user.o
+
 common-obj-$(CONFIG_VIRTIO_RNG) += virtio-rng.o
 common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
 common-obj-$(CONFIG_VIRTIO_MMIO) += virtio-mmio.o
 obj-$(CONFIG_VIRTIO_BALLOON) += virtio-balloon.o
 obj-$(CONFIG_VIRTIO_CRYPTO) += virtio-crypto.o
 obj-$(call land,$(CONFIG_VIRTIO_CRYPTO),$(CONFIG_VIRTIO_PCI)) += virtio-crypto-pci.o
-
-obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o
 obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock.o
+
 ifeq ($(CONFIG_VIRTIO_PCI),y)
 obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-pci.o
 obj-$(CONFIG_VHOST_USER_BLK) += vhost-user-blk-pci.o
@@ -28,5 +31,4 @@ obj-$(CONFIG_VIRTIO_SERIAL) += virtio-serial-pci.o
 endif
 endif
 
-common-obj-$(call lnot,$(call land,$(CONFIG_VIRTIO),$(CONFIG_LINUX))) += vhost-stub.o
 common-obj-$(CONFIG_ALL) += vhost-stub.o

hw/virtio/vhost-backend.c

@@ -9,11 +9,14 @@
  */
 
 #include "qemu/osdep.h"
-#include <linux/vhost.h>
-#include <sys/ioctl.h>
 #include "hw/virtio/vhost.h"
 #include "hw/virtio/vhost-backend.h"
 #include "qemu/error-report.h"
+#include "standard-headers/linux/vhost_types.h"
+
+#ifdef CONFIG_LINUX
+#include <linux/vhost.h>
+#include <sys/ioctl.h>
 
 static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
                              void *arg)
@@ -265,18 +268,23 @@ static const VhostOps kernel_ops = {
         .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
         .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
 };
+#endif
 
 int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
 {
     int r = 0;
 
     switch (backend_type) {
+#ifdef CONFIG_LINUX
     case VHOST_BACKEND_TYPE_KERNEL:
         dev->vhost_ops = &kernel_ops;
         break;
+#endif
+#ifdef CONFIG_VHOST_USER
     case VHOST_BACKEND_TYPE_USER:
         dev->vhost_ops = &user_ops;
         break;
+#endif
     default:
         error_report("Unknown vhost backend type");
         r = -1;

hw/virtio/vhost-user.c

@@ -27,8 +27,12 @@
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/un.h>
-#include <linux/vhost.h>
+
+#include "standard-headers/linux/vhost_types.h"
+
+#ifdef CONFIG_LINUX
 #include <linux/userfaultfd.h>
+#endif
 
 #define VHOST_MEMORY_MAX_NREGIONS    8
 #define VHOST_USER_F_PROTOCOL_FEATURES 30
@@ -1110,6 +1114,7 @@ out:
     return ret;
 }
 
+#ifdef CONFIG_LINUX
 /*
  * Called back from the postcopy fault thread when a fault is received on our
  * ufd.
@@ -1177,6 +1182,7 @@ static int vhost_user_postcopy_waker(struct PostCopyFD *pcfd, RAMBlock *rb,
     trace_vhost_user_postcopy_waker_nomatch(qemu_ram_get_idstr(rb), offset);
     return 0;
 }
+#endif
 
 /*
  * Called at the start of an inbound postcopy on reception of the
@@ -1184,6 +1190,7 @@ static int vhost_user_postcopy_waker(struct PostCopyFD *pcfd, RAMBlock *rb,
  */
 static int vhost_user_postcopy_advise(struct vhost_dev *dev, Error **errp)
 {
+#ifdef CONFIG_LINUX
     struct vhost_user *u = dev->opaque;
     CharBackend *chr = u->user->chr;
     int ufd;
@@ -1227,6 +1234,10 @@ static int vhost_user_postcopy_advise(struct vhost_dev *dev, Error **errp)
     u->postcopy_fd.idstr = "vhost-user"; /* Need to find unique name */
     postcopy_register_shared_ufd(&u->postcopy_fd);
     return 0;
+#else
+    error_setg(errp, "Postcopy not supported on non-Linux systems");
+    return -1;
+#endif
 }
 
 /*

hw/virtio/vhost.c

@@ -21,7 +21,7 @@
 #include "qemu/range.h"
 #include "qemu/error-report.h"
 #include "qemu/memfd.h"
-#include <linux/vhost.h>
+#include "standard-headers/linux/vhost_types.h"
 #include "exec/address-spaces.h"
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"