[PATCH] xen: fix condition for enabling the Xen accelerator

[Paolo Bonzini]

A misspelled condition in xen_native.h is hiding a bug in the enablement of
Xen for qemu-system-aarch64.  The bug becomes apparent when building for
Xen 4.18.

While the i386 emulator provides the xenpv machine type for multiple 
architectures,
and therefore can be compiled with Xen enabled even when the host is Arm, the
opposite is not true: qemu-system-aarch64 can only be compiled with Xen support
enabled when the host is Arm.

Expand the computation of accelerator_targets['CONFIG_XEN'] similar to what is
already there for KVM, and fix xen_native.h.

Cc: Stefano Stabellini <stefano.stabellini@amd.com>
Cc: Richard W.M. Jones <rjones@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Reported-by: Michael Young <m.a.young@durham.ac.uk>
Supersedes: 
<277e21fc78b75ec459efc7f5fde628a0222c63b0.1701989261.git.m.a.young@durham.ac.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/hw/xen/xen_native.h |  2 +-
 meson.build                 | 17 ++++++++++-------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/hw/xen/xen_native.h b/include/hw/xen/xen_native.h
index 6f09c48823b..1a5ad693a4d 100644
--- a/include/hw/xen/xen_native.h
+++ b/include/hw/xen/xen_native.h
@@ -532,7 +532,7 @@ static inline int 
xendevicemodel_set_irq_level(xendevicemodel_handle *dmod,
 }
 #endif
 
-#if CONFIG_XEN_CTRL_INTERFACE_VERSION <= 41700
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41700
 #define GUEST_VIRTIO_MMIO_BASE   xen_mk_ullong(0x02000000)
 #define GUEST_VIRTIO_MMIO_SIZE   xen_mk_ullong(0x00100000)
 #define GUEST_VIRTIO_MMIO_SPI_FIRST   33
diff --git a/meson.build b/meson.build
index ec01f8b138a..67f4ede8aea 100644
--- a/meson.build
+++ b/meson.build
@@ -123,21 +123,24 @@ if get_option('kvm').allowed() and targetos == 'linux'
   kvm_targets_c = '"' + '" ,"'.join(kvm_targets) + '"'
 endif
 config_host_data.set('CONFIG_KVM_TARGETS', kvm_targets_c)
-
 accelerator_targets = { 'CONFIG_KVM': kvm_targets }
 
+if cpu in ['x86', 'x86_64']
+  xen_targets = ['i386-softmmu', 'x86_64-softmmu']
+elif cpu in ['arm', 'aarch64']
+  # i386 emulator provides xenpv machine type for multiple architectures
+  xen_targets = ['i386-softmmu', 'x86_64-softmmu', 'aarch64-softmmu']
+else
+  xen_targets = []
+endif
+accelerator_targets += { 'CONFIG_XEN': xen_targets }
+
 if cpu in ['aarch64']
   accelerator_targets += {
     'CONFIG_HVF': ['aarch64-softmmu']
   }
 endif
 
-if cpu in ['x86', 'x86_64', 'arm', 'aarch64']
-  # i386 emulator provides xenpv machine type for multiple architectures
-  accelerator_targets += {
-    'CONFIG_XEN': ['i386-softmmu', 'x86_64-softmmu', 'aarch64-softmmu'],
-  }
-endif
 if cpu in ['x86', 'x86_64']
   accelerator_targets += {
     'CONFIG_HVF': ['x86_64-softmmu'],
-- 
2.43.0