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Subject[PATCH 07/24] xen/arm: Xen detection and shared_info page mapping
Date
Check for a "/xen" node in the device tree, if it is present set
xen_domain_type to XEN_HVM_DOMAIN and continue initialization.

Map the real shared info page using XENMEM_add_to_physmap with
XENMAPSPACE_shared_info.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
arch/arm/xen/enlighten.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 56 insertions(+), 0 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index d27c2a6..8c923af 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -5,6 +5,9 @@
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>

struct start_info _xen_start_info;
struct start_info *xen_start_info = &_xen_start_info;
@@ -33,3 +36,56 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
return -ENOSYS;
}
EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
+
+/*
+ * == Xen Device Tree format ==
+ * - /xen node;
+ * - compatible "arm,xen";
+ * - one interrupt for Xen event notifications;
+ * - one memory region to map the grant_table.
+ */
+static int __init xen_guest_init(void)
+{
+ int cpu;
+ struct xen_add_to_physmap xatp;
+ static struct shared_info *shared_info_page = 0;
+ struct device_node *node;
+
+ node = of_find_compatible_node(NULL, NULL, "arm,xen");
+ if (!node) {
+ pr_info("No Xen support\n");
+ return 0;
+ }
+ xen_domain_type = XEN_HVM_DOMAIN;
+
+ if (!shared_info_page)
+ shared_info_page = (struct shared_info *)
+ get_zeroed_page(GFP_KERNEL);
+ if (!shared_info_page) {
+ pr_err("not enough memory");
+ return -ENOMEM;
+ }
+ xatp.domid = DOMID_SELF;
+ xatp.idx = 0;
+ xatp.space = XENMAPSPACE_shared_info;
+ xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
+ if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
+ BUG();
+
+ HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
+
+ /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
+ * page, we use it in the event channel upcall and in some pvclock
+ * related functions. We don't need the vcpu_info placement
+ * optimizations because we don't use any pv_mmu or pv_irq op on
+ * HVM.
+ * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
+ * online but xen_hvm_init_shared_info is run at resume time too and
+ * in that case multiple vcpus might be online. */
+ for_each_online_cpu(cpu) {
+ per_cpu(xen_vcpu, cpu) =
+ &HYPERVISOR_shared_info->vcpu_info[cpu];
+ }
+ return 0;
+}
+core_initcall(xen_guest_init);
--
1.7.2.5


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