Commit 2e01f166 authored by Stefano Stabellini's avatar Stefano Stabellini
Browse files

xen/arm: Xen detection and shared_info page mapping 



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: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
parent c43cdfbc

arch/arm/xen/enlighten.c

+61 −0
Original line number Diff line number Diff line
@@ -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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE