Re: [PATCH v2 07/23] xen/arm: Xen detection and shared_info page mapping

Konrad Rzeszutek Wilk
2012-08-07T18:27:38Z

On Mon, Aug 06, 2012 at 03:27:10PM +0100, Stefano Stabellini wrote:
> 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.
>
> Changes in v2:
>
> - replace pr_info with pr_debug.

I second what David mentioned. The other thing is that you are going to
need to rebase this on top of v3.5-rc1, as Olaf's patches have changed
the shared_info_page a bit.

>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> ---
> arch/arm/xen/enlighten.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 52 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index d27c2a6..102d823 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 +36,52 @@ 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)
> +{
> + 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_debug("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\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);
> --
> 1.7.2.5