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

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 14 Jun 2018, Julien Grall wrote:
> 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.

I'll remove the comment


> > 
> > 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.

Yes, I'll extend allocate_memory to respect the current domU memory layout.


> > +
> > +    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,

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