Re: [Xen-devel] [PATCH v3 2/3] xen/privcmd: Add IOCTL_PRIVCMD_DM_OP

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

On 13 February 2017, at 19:11, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> wrote:

>
>
>> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
>> index 5e5c7ae..a33f17e 100644
>> --- a/drivers/xen/privcmd.c
>> +++ b/drivers/xen/privcmd.c
>> @@ -22,6 +22,7 @@
>>  #include <linux/pagemap.h>
>>  #include <linux/seq_file.h>
>>  #include <linux/miscdevice.h>
>> +#include <linux/moduleparam.h>
>>
>>  #include <asm/pgalloc.h>
>>  #include <asm/pgtable.h>
>> @@ -32,6 +33,7 @@
>>  #include <xen/xen.h>
>>  #include <xen/privcmd.h>
>>  #include <xen/interface/xen.h>
>> +#include <xen/interface/hvm/dm_op.h>
>>  #include <xen/features.h>
>>  #include <xen/page.h>
>>  #include <xen/xen-ops.h>
>> @@ -43,6 +45,17 @@ MODULE_LICENSE("GPL");
>>
>>  #define PRIV_VMA_LOCKED ((void *)1)
>>
>> +unsigned int privcmd_dm_op_max_num = 16;
>> +module_param_named(dm_op_max_nr_bufs, privcmd_dm_op_max_num, uint, 0644);
>> +MODULE_PARM_DESC(dm_op_max_nr_bufs,
>> +              "Maximum number of buffers per dm_op hypercall");
>> +
>> +unsigned int privcmd_dm_op_buf_max_size = XEN_PAGE_SIZE;
>These need to be static. (I can fix it when committing.)

OK. Thanks.

>And I am still not sure about using XEN_PAGE_SIZE. There is no
>dependency in the hypervisor on buffers being page-sized, is there? If
>not, XEN_PAGE_SIZE is here just because it happens to be 4K, which is a
>reasonable value.
>How about just setting it to 4096?

I chose XEN_PAGE_SIZE because the hypercall will eventually copy in the buffer so it seemed like a reasonable value to use. If you want to just use 4096 then I am ok with that.

  Paul

>-boris
>

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