Re: [libvirt] [Xen-devel] [PATCH] libxl: Correctly initialize vcpu bitmap

[Jim Fehlig <jfehlig@suse.com>]

One comment below in addition to Konrad's...

Konrad Rzeszutek Wilk wrote:
> On Mon, Jul 22, 2013 at 12:51:05PM +0200, Stefan Bader wrote:
>   
>> This fixes the basic setup but there is likely more to do if things
>> like manual CPU hirarchy (nodes, cores, threads) to be working.
>>
>> Cross-posting to xen-devel to make sure I am doing things correctly.
>>
>> -Stefan
>>
>>
>> >From 1ec5e7ea0d3498b9f61b83e8aed87cc3cae106de Mon Sep 17 00:00:00 2001
>> From: Stefan Bader <stefan.bader@canonical.com>
>> Date: Fri, 19 Jul 2013 15:20:00 +0200
>> Subject: [PATCH] libxl: Correctly initialize vcpu bitmap
>>
>> The avai_vcpu bitmap has to be allocated before it can be used (using
>>     
>
> avail_vcpu ?
>
>   
>> the maximum allowed value for that). Then for each available VCPU the
>> bit in the mask has to be set (libxl_bitmap_set takes a bit position
>> as an argument, not the number of bits to set).
>>
>> Without this, I would always only get one VCPU for guests created
>> through libvirt/libxl.
>>
>> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
>>     
>
> The libxl calling logic looks Ok to me. So from the libxl perspective
> you can tack on Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>
>   
>> ---
>>  src/libxl/libxl_conf.c |   14 +++++++++++---
>>  1 file changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
>> index 4a0fba9..7592dd2 100644
>> --- a/src/libxl/libxl_conf.c
>> +++ b/src/libxl/libxl_conf.c
>> @@ -331,7 +331,8 @@ error:
>>  }
>>  
>>  static int
>> -libxlMakeDomBuildInfo(virDomainDefPtr def, libxl_domain_config *d_config)
>> +libxlMakeDomBuildInfo(libxlDriverPrivatePtr driver, virDomainDefPtr def,
>> +                      libxl_domain_config *d_config)
>>  {
>>      libxl_domain_build_info *b_info = &d_config->b_info;
>>      int hvm = STREQ(def->os.type, "hvm");
>> @@ -343,8 +344,15 @@ libxlMakeDomBuildInfo(virDomainDefPtr def, libxl_domain_config *d_config)
>>          libxl_domain_build_info_init_type(b_info, LIBXL_DOMAIN_TYPE_HVM);
>>      else
>>          libxl_domain_build_info_init_type(b_info, LIBXL_DOMAIN_TYPE_PV);
>> +
>>      b_info->max_vcpus = def->maxvcpus;
>> -    libxl_bitmap_set((&b_info->avail_vcpus), def->vcpus);
>> +    if (libxl_cpu_bitmap_alloc(driver->ctx, &b_info->avail_vcpus,
>> +                               def->maxvcpus))
>>     

You are using the driver-wide libxl_ctx in libxlDriverPrivate here, but
should be using the per-domain libxl_ctx in libxlDomainObjPrivate
structure IMO.

It looks like libxlBuildDomainConfig, which calls libxlMakeDomBuildInfo,
should have just taken virDomainObjPtr instead of virDomainDefPtr. 
libxlBuildDomainConfig would then have access to the per-domain
libxl_ctx, and no longer need the libxlDriverPrivatePtr parameter as well.

Regards,
Jim

>> +        goto error;
>> +    libxl_bitmap_set_none(&b_info->avail_vcpus);
>> +    for (i = 0; i < def->vcpus; i++)
>> +        libxl_bitmap_set((&b_info->avail_vcpus), i);
>> +
>>      if (def->clock.ntimers > 0 &&
>>          def->clock.timers[0]->name == VIR_DOMAIN_TIMER_NAME_TSC) {
>>          switch (def->clock.timers[0]->mode) {
>> @@ -802,7 +810,7 @@ libxlBuildDomainConfig(libxlDriverPrivatePtr driver,
>>      if (libxlMakeDomCreateInfo(driver, def, &d_config->c_info) < 0)
>>          return -1;
>>  
>> -    if (libxlMakeDomBuildInfo(def, d_config) < 0) {
>> +    if (libxlMakeDomBuildInfo(driver, def, d_config) < 0) {
>>          return -1;
>>      }
>>  
>> -- 
>> 1.7.9.5
>>
>>
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>>     
>
>