Re: [Xen-devel] [PATCH RFC 10/15] xen/arm: introduce construct_domU

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 13/06/18 23:15, Stefano Stabellini wrote:
> Similar to construct_dom0, construct_domU creates a barebone DomU guest.
> Default to 1 max vcpu and 64MB of memory if not specified otherwise.
>
> The device tree node passed as argument is compatible "xen,domU", see
> docs/misc/arm/device-tree/booting.txt.
>
> Allocate all vcpus on cpu0 initially.
I don't think this comment is true. __construct_domain will allocate 
vCPUs in cycle.
> Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
> ---
>   xen/arch/arm/domain_build.c | 37 +++++++++++++++++++++++++++++++++++++
>   xen/include/asm-arm/setup.h |  2 ++
>   2 files changed, 39 insertions(+)
>
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index b31c563..02a7f94 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -2187,6 +2187,43 @@ int __init __construct_domain(struct domain *d, struct 
> kernel_info *kinfo)
>       return 0;
>   }
>   
> +int __init construct_domU(struct domain *d, struct dt_device_node *node)
> +{
> +    struct kernel_info kinfo = {};
> +    int rc;
> +    const char *cpus = NULL, *mem = NULL;
> +
> +    printk("*** LOADING DOMU ***\n");
> +
> +    d->max_vcpus = 1;
> +    rc = dt_property_read_string(node, "cpus", &cpus);
> +    if ( !rc )
> +        d->max_vcpus = simple_strtoul(cpus, &cpus, 0);
> +
> +    kinfo.unassigned_mem = MB(64);
> +    rc = dt_property_read_string(node, "mem", &mem);
> +    if ( !rc )
> +        kinfo.unassigned_mem = parse_size_and_unit(mem, &mem);
> +
> +    d->vcpu = xzalloc_array(struct vcpu *, d->max_vcpus);
> +    if ( !d->vcpu )
> +        return -ENOMEM;;
> +    if ( alloc_vcpu(d, 0, 0) == NULL )
> +        return -ENOMEM;
> +    d->max_pages = ~0U;
> +
> +    kinfo.d = d;
> +
> +    rc = kernel_probe_domU(&kinfo, node);
> +    if ( rc < 0 )
> +        return rc;
> +
> +    d->arch.type = kinfo.type;
> +    allocate_memory(d, &kinfo);
allocate_memory() will allocate direct mapped memory but you impose a 
static memory layout for the guest. Both are not going to work very well 
together.
So you probably want to extend allocate_memory to support allocating 
memory for a given region.
> +
> +    return __construct_domain(d, &kinfo);
> +}
> +
>   int __init construct_dom0(struct domain *d)
>   {
>       struct kernel_info kinfo = {};
> diff --git a/xen/include/asm-arm/setup.h b/xen/include/asm-arm/setup.h
> index 903782f..e9f9905 100644
> --- a/xen/include/asm-arm/setup.h
> +++ b/xen/include/asm-arm/setup.h
> @@ -2,6 +2,7 @@
>   #define __ARM_SETUP_H_
>   
>   #include <public/version.h>
> +#include <xen/device_tree.h>
>   
>   #define MIN_FDT_ALIGN 8
>   #define MAX_FDT_SIZE SZ_2M
> @@ -71,6 +72,7 @@ void acpi_create_efi_mmap_table(struct domain *d,
>   int acpi_make_efi_nodes(void *fdt, struct membank tbl_add[]);
>   
>   int construct_dom0(struct domain *d);
> +int construct_domU(struct domain *d, struct dt_device_node *node);
>   
>   void discard_initial_modules(void);
>   void dt_unreserved_regions(paddr_t s, paddr_t e,
Cheers,

--
Julien Grall

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