Re: [Xen-devel] [PATCH v3 1/2] xen: vnuma for pv guests

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Tue, Jun 03, 2014 at 12:54:39AM -0400, Elena Ufimtseva wrote:
> Issues Xen hypercall subop XENMEM_get_vnumainfo and sets the
> NUMA topology, otherwise sets dummy NUMA node and prevents
> numa_init from calling other numa initializators as they dont
> work with pv guests.

We should also have a bit of details of the hypercalls, what
the data structures are, when this hypercall was introduced etc.

I would expect at least two or three paragraphs of it. But
it should wait until the Xen parts have been implemented.

> 
> Signed-off-by: Elena Ufimtseva <ufimtseva@xxxxxxxxx>
> ---
>  arch/x86/include/asm/xen/vnuma.h |   10 ++++
>  arch/x86/mm/numa.c               |    3 +
>  arch/x86/xen/Makefile            |    1 +
>  arch/x86/xen/setup.c             |    6 +-
>  arch/x86/xen/vnuma.c             |  121 
> ++++++++++++++++++++++++++++++++++++++
>  include/xen/interface/memory.h   |   50 ++++++++++++++++
>  6 files changed, 190 insertions(+), 1 deletion(-)
>  create mode 100644 arch/x86/include/asm/xen/vnuma.h
>  create mode 100644 arch/x86/xen/vnuma.c
> 
> diff --git a/arch/x86/include/asm/xen/vnuma.h 
> b/arch/x86/include/asm/xen/vnuma.h
> new file mode 100644
> index 0000000..8c8b098
> --- /dev/null
> +++ b/arch/x86/include/asm/xen/vnuma.h
> @@ -0,0 +1,10 @@
> +#ifndef _ASM_X86_VNUMA_H
> +#define _ASM_X86_VNUMA_H
> +
> +#ifdef CONFIG_XEN
> +int xen_numa_init(void);
> +#else
> +static inline int xen_numa_init(void) { return -1; };
> +#endif
> +
> +#endif /* _ASM_X86_VNUMA_H */
> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 1d045f9..37a9c84 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -18,6 +18,7 @@
>  #include <asm/acpi.h>
>  #include <asm/amd_nb.h>
>  
> +#include "asm/xen/vnuma.h"
>  #include "numa_internal.h"
>  
>  int __initdata numa_off;
> @@ -687,6 +688,8 @@ static int __init dummy_numa_init(void)
>  void __init x86_numa_init(void)
>  {
>       if (!numa_off) {
> +             if (!numa_init(xen_numa_init))
> +                     return;
>  #ifdef CONFIG_ACPI_NUMA
>               if (!numa_init(x86_acpi_numa_init))
>                       return;
> diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
> index 96ab2c0..185ec9b 100644
> --- a/arch/x86/xen/Makefile
> +++ b/arch/x86/xen/Makefile
> @@ -22,3 +22,4 @@ obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
>  obj-$(CONFIG_XEN_DEBUG_FS)   += debugfs.o
>  obj-$(CONFIG_XEN_DOM0)               += apic.o vga.o
>  obj-$(CONFIG_SWIOTLB_XEN)    += pci-swiotlb-xen.o
> +obj-$(CONFIG_NUMA)           += vnuma.o
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index 0982233..0235f19 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -20,6 +20,7 @@
>  #include <asm/numa.h>
>  #include <asm/xen/hypervisor.h>
>  #include <asm/xen/hypercall.h>
> +#include <asm/xen/vnuma.h>
>  
>  #include <xen/xen.h>
>  #include <xen/page.h>
> @@ -622,6 +623,9 @@ void __init xen_arch_setup(void)
>       WARN_ON(xen_set_default_idle());
>       fiddle_vdso();
>  #ifdef CONFIG_NUMA
> -     numa_off = 1;
> +     if (xen_initial_domain())
> +             numa_off = 1;
> +     else
> +             numa_off = 0;
>  #endif
>  }
> diff --git a/arch/x86/xen/vnuma.c b/arch/x86/xen/vnuma.c
> new file mode 100644
> index 0000000..a02f9c6
> --- /dev/null
> +++ b/arch/x86/xen/vnuma.c
> @@ -0,0 +1,121 @@
> +#include <linux/err.h>
> +#include <linux/memblock.h>
> +#include <xen/interface/xen.h>
> +#include <xen/interface/memory.h>
> +#include <asm/xen/interface.h>
> +#include <asm/xen/hypercall.h>
> +#include <asm/xen/vnuma.h>
> +
> +/*
> + * Called from numa_init if numa_off = 0;

How about: Set all of the generic node APIs with NUMA
information.

> + */
> +int __init xen_numa_init(void)
> +{
> +     unsigned int i, j, idx;
> +     unsigned int cpu, pcpus, nr_nodes, nr_cpus;
> +     unsigned int *vdistance, *cpu_to_node;
> +     unsigned long mem_size, dist_size, cpu_to_node_size;
> +     struct vmemrange *vmem;
> +     u64 physm, physd, physc;
> +     int rc;
> +
> +     struct vnuma_topology_info numa_topo = {
> +             .domid = DOMID_SELF
> +     };
> +
> +     rc = -EINVAL;
> +     physm = physd = physc = 0;
> +
> +     /* For now only PV guests are supported */

Full stop missing.
> +     if (!xen_pv_domain())
> +             return rc;
> +
> +     /* get the number of nodes for allocation of memblocks */

Ditto.
> +     pcpus = num_possible_cpus();
> +     nr_cpus = setup_max_cpus < pcpus ? setup_max_cpus : pcpus;
> +
> +     /* support for nodes with at least one cpu */
.. per node?

> +     nr_nodes = nr_cpus;
> +
> +     /*
> +      * Allocate arrays for nr_cpus/nr_nodes sizes and let
> +      * hypervisor know that these are the boundaries. Partial
> +      * copy is not allowed and hypercall will fail.
> +      */
> +
> +     mem_size =  nr_nodes * sizeof(struct vmemrange);
> +     dist_size = nr_nodes * nr_nodes * sizeof(*numa_topo.distance.h);
> +     cpu_to_node_size = nr_cpus * sizeof(*numa_topo.cpu_to_node.h);
> +
> +     physm = memblock_alloc(mem_size, PAGE_SIZE);
> +     physd = memblock_alloc(dist_size, PAGE_SIZE);
> +     physc = memblock_alloc(cpu_to_node_size, PAGE_SIZE);
> +
> +     if (!physm || !physd || !physc)
> +             goto out;
> +
> +     vmem = __va(physm);
> +     vdistance  = __va(physd);
> +     cpu_to_node  = __va(physc);
> +
> +     numa_topo.nr_nodes = nr_nodes;
> +     numa_topo.nr_cpus = nr_cpus;
> +
> +     set_xen_guest_handle(numa_topo.memrange.h, vmem);
> +     set_xen_guest_handle(numa_topo.distance.h, vdistance);
> +     set_xen_guest_handle(numa_topo.cpu_to_node.h, cpu_to_node);
> +
> +     if (HYPERVISOR_memory_op(XENMEM_get_vnuma_info, &numa_topo) < 0)
> +             goto out;
> +
> +     /*
> +      * NUMA nodes memory ranges are in pfns, constructed and
> +      * aligned based on e820 ram domain map.
> +      */
> +     for (i = 0; i < nr_nodes; i++) {
> +             if (numa_add_memblk(i, vmem[i].start, vmem[i].end))
> +                     goto out;
> +             node_set(i, numa_nodes_parsed);
> +     }
> +
> +     setup_nr_node_ids();
> +     /* Setting the cpu, apicid to node */
> +     for_each_cpu(cpu, cpu_possible_mask) {
> +             set_apicid_to_node(cpu, cpu_to_node[cpu]);
> +             numa_set_node(cpu, cpu_to_node[cpu]);
> +             cpumask_set_cpu(cpu, node_to_cpumask_map[cpu_to_node[cpu]]);
> +     }
> +
> +     for (i = 0; i < nr_nodes; i++) {
> +             for (j = 0; j < nr_nodes; j++) {
> +                     idx = (i * nr_nodes) + j;
> +                     numa_set_distance(i, j, *(vdistance + idx));
> +             }
> +     }
> +
> +     rc = 0;
> +out:
> +     if (physm)
> +             memblock_free(__pa(physm), mem_size);
> +     if (physd)
> +             memblock_free(__pa(physd), dist_size);
> +     if (physc)
> +             memblock_free(__pa(physc), cpu_to_node_size);
> +     /*
> +      * Set a dummy node and return success.  This prevents calling any
> +      * hardware-specific initializers which do not work in a PV guest.
> +      * Taken from dummy_numa_init code.
> +      */
> +     if (rc != 0) {

if (rc)

> +             for (i = 0; i < MAX_LOCAL_APIC; i++)
> +                     set_apicid_to_node(i, NUMA_NO_NODE);
> +             nodes_clear(numa_nodes_parsed);
> +             nodes_clear(node_possible_map);
> +             nodes_clear(node_online_map);
> +             node_set(0, numa_nodes_parsed);
> +             /* cpus up to max_cpus will be assigned to one node */
> +             numa_add_memblk(0, 0, PFN_PHYS(max_pfn));
> +             setup_nr_node_ids();
> +     }
> +     return 0;
> +}
> diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
> index 2ecfe4f..96d6387 100644
> --- a/include/xen/interface/memory.h
> +++ b/include/xen/interface/memory.h
> @@ -263,4 +263,54 @@ struct xen_remove_from_physmap {
>  };
>  DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);
>  
> +/* vNUMA structures */
> +struct vmemrange {
> +     uint64_t start, end;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(vmemrange);
> +
> +struct vnuma_topology_info {
> +     /* OUT */
> +     domid_t domid;
> +     /*
> +      * nr_nodes and nr_cpus are used for retreival of sizes
> +      * of will be allocated arrays for vnuma topology.
> +      * We need to know vcpus numberfor domain as NR_CPUS
> +      * is less then domain max_vcpus, number of possible
> +      * cpus will equal to NR_CPUS and we have no way of
> +      * learning domain vcpus number.
> +      */
> +     /* number of virtual numa nodes */
> +     unsigned int nr_nodes;
> +     unsigned int nr_cpus;
> +     /* distance table */
> +     union {
> +             GUEST_HANDLE(uint) h;
> +             uint64_t    _pad;
> +     } distance;
> +     /* cpu mapping to vnodes */
> +     union {
> +             GUEST_HANDLE(uint) h;
> +             uint64_t    _pad;
> +     } cpu_to_node;
> +     /*
> +     * memory areas constructed by Xen, start and end
> +     * of the ranges are specific to domain e820 map.
> +     * Xen toolstack constructs these ranges for domain
> +     * when building it.
> +     */
> +     union {
> +             GUEST_HANDLE(vmemrange) h;
> +             uint64_t    _pad;
> +     } memrange;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(vnuma_topology_info);
> +
> +/*
> + * Used to retreive vnuma topology info.
> + * Use XENMEM_get_vnuma_nodes to obtain number of
> + * nodes before allocating memory for topology.
> + */
> +#define XENMEM_get_vnuma_info        26
> +
>  #endif /* __XEN_PUBLIC_MEMORY_H__ */
> -- 
> 1.7.10.4
> 

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