Re: [Xen-devel] [PATCH v2 12/19] hvmloader: retrieve vNUMA information from hypervisor

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.12.14 at 16:33, <wei.liu2@xxxxxxxxxx> wrote:
> @@ -261,6 +262,8 @@ int main(void)
>  
>      init_hypercalls();
>  
> +    init_vnuma_info();

This is very early, and I don't think it needs to be - I guess it could be
done right before doing ACPI stuff?

> --- /dev/null
> +++ b/tools/firmware/hvmloader/vnuma.c
> @@ -0,0 +1,84 @@
> +/*
> + * vnuma.c: obtain vNUMA information from hypervisor
> + *
> + * Copyright (c) 2014 Wei Liu, Citrix Systems (R&D) Ltd.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#include "util.h"
> +#include "hypercall.h"
> +#include "vnuma.h"
> +#include <errno.h>

This is the system header, not the Xen one. See the discussion at
http://lists.xenproject.org/archives/html/xen-devel/2014-10/msg03206.html
and perhaps build on the resulting patch
http://lists.xenproject.org/archives/html/xen-devel/2014-12/msg00013.html.

> +
> +unsigned int nr_vnodes, nr_vmemranges;
> +unsigned int *vcpu_to_vnode, *vdistance;
> +xen_vmemrange_t *vmemrange;
> +
> +void init_vnuma_info(void)
> +{
> +    int rc, retry = 0;
> +    struct xen_vnuma_topology_info vnuma_topo = {
> +        .domid = DOMID_SELF,
> +    };
> +
> +    vcpu_to_vnode = scratch_alloc(sizeof(uint32_t) * hvm_info->nr_vcpus, 0);
> +    vdistance = scratch_alloc(sizeof(uint32_t) * MAX_VDISTANCE, 0);
> +    vmemrange = scratch_alloc(sizeof(xen_vmemrange_t) * MAX_VMEMRANGES, 0);
> +
> +    vnuma_topo.nr_vnodes = MAX_VNODES;
> +    vnuma_topo.nr_vcpus = hvm_info->nr_vcpus;
> +    vnuma_topo.nr_vmemranges = MAX_VMEMRANGES;
> +
> +    set_xen_guest_handle(vnuma_topo.vdistance.h, vdistance);
> +    set_xen_guest_handle(vnuma_topo.vcpu_to_vnode.h, vcpu_to_vnode);
> +    set_xen_guest_handle(vnuma_topo.vmemrange.h, vmemrange);
> +
> +    rc = hypercall_memory_op(XENMEM_get_vnumainfo, &vnuma_topo);
> +    while ( rc == -EAGAIN && retry < 10 )
> +    {
> +        rc = hypercall_memory_op(XENMEM_get_vnumainfo, &vnuma_topo);
> +        retry++;
> +    }
> +    if ( rc < 0 )
> +    {
> +        printf("Failed to retrieve vNUMA information, rc = %d\n", rc);
> +        goto out;

return;

> +    }
> +
> +    nr_vnodes = vnuma_topo.nr_vnodes;
> +    nr_vmemranges = vnuma_topo.nr_vmemranges;
> +
> +out:
> +    return;

Drop these two (or really three) unnecessary lines please.

> --- /dev/null
> +++ b/tools/firmware/hvmloader/vnuma.h
> @@ -0,0 +1,56 @@
> +/******************************************************************************
> + * vnuma.h
> + *
> + * Copyright (c) 2014, Wei Liu
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation; or, when distributed
> + * separately from the Linux kernel or incorporated into other
> + * software packages, subject to the following license:
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a 
> copy
> + * of this source file (the "Software"), to deal in the Software without
> + * restriction, including without limitation the rights to use, copy, modify,
> + * merge, publish, distribute, sublicense, and/or sell copies of the 
> Software,
> + * and to permit persons to whom the Software is furnished to do so, subject 
> to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 
> THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
> DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#ifndef __HVMLOADER_VNUMA_H__
> +#define __HVMLOADER_VNUMA_H__
> +
> +#include <xen/memory.h>
> +
> +#define MAX_VNODES     64
> +#define MAX_VDISTANCE  (MAX_VNODES * MAX_VNODES)
> +#define MAX_VMEMRANGES (MAX_VNODES * 2)

These look arbitrary - please add a (brief) comment giving some
rationale so that people needing to change them know eventual
consequences. Would it perhaps make sense to derive
MAX_VNODES from HVM_MAX_VCPUS? Additionally I think the
code wouldn't become much more difficult if you didn't build in
static upper limits.

Jan

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