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xen/arm: Xen detection and shared_info page mapping

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Check for a node in the device tree compatible with "xen,xen", 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.

Changes in v4:

- simpler parsing of Xen version in the compatible DT node.

Changes in v3:

- use the "xen,xen" notation rather than "arm,xen";
- add an additional check on the presence of the Xen version.

Changes in v2:

- replace pr_info with pr_debug.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
Stefano Stabellini 2012-09-14 10:47:52 +00:00
parent c43cdfbc4c
commit 2e01f16601
1 changed files with 61 additions and 0 deletions
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61
arch/arm/xen/enlighten.c
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@ -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 +36,61 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
return -ENOSYS;
}
EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
/*
* see Documentation/devicetree/bindings/arm/xen.txt for the
* documentation of the Xen Device Tree format.
*/
static int __init xen_guest_init(void)
{
struct xen_add_to_physmap xatp;
static struct shared_info *shared_info_page = 0;
struct device_node *node;
int len;
const char *s = NULL;
const char *version = NULL;
const char *xen_prefix = "xen,xen-";
node = of_find_compatible_node(NULL, NULL, "xen,xen");
if (!node) {
pr_debug("No Xen support\n");
return 0;
}
s = of_get_property(node, "compatible", &len);
if (strlen(xen_prefix) + 3 < len &&
!strncmp(xen_prefix, s, strlen(xen_prefix)))
version = s + strlen(xen_prefix);
if (version == NULL) {
pr_debug("Xen version not found\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\n");
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.
* The shared info contains exactly 1 CPU (the boot CPU). The guest
* is required to use VCPUOP_register_vcpu_info to place vcpu info
* for secondary CPUs as they are brought up. */
per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
return 0;
}
core_initcall(xen_guest_init);