Re: [Xen-devel] [PATCH v2 1/3] x86/mem_access: Make the mem_access ops generic

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.04.14 at 00:02, <aravindp@xxxxxxxxx> wrote:
> -int mem_access_memop(struct domain *d, xen_mem_event_op_t *meo)
> +int mem_access_memop(unsigned long cmd,
> +                     XEN_GUEST_HANDLE_PARAM(xen_mem_access_op_t) arg)
>  {
> -    int rc;
> +    long rc;
> +    xen_mem_access_op_t mao;
> +    struct domain *d;
> +
> +    if ( copy_from_guest(&mao, arg, 1) )
> +        return -EFAULT;
> +
> +    rc = rcu_lock_live_remote_domain_by_id(mao.domid, &d);
> +    if ( rc )
> +        return rc;
> +
> +    if ( !is_hvm_domain(d) )
> +        return -EINVAL;
> +
> +    rc = xsm_mem_event_op(XSM_TARGET, d, XENMEM_access_op);
> +    if ( rc )
> +        goto out;
>  
>      if ( unlikely(!d->mem_event->access.ring_page) )
>          return -ENODEV;

This and the earlier return need to become "goto out".

>  
> -    switch( meo->op )
> +    switch ( mao.op )
>      {
>      case XENMEM_access_op_resume:
>      {
>          p2m_mem_access_resume(d);
>          rc = 0;
> +        break;
> +    }

Please remove the pointless opening brace rather than adding a closing
one here.

> +
> +    case XENMEM_access_op_set_access:
> +    {
> +        unsigned long start_iter = cmd & ~MEMOP_CMD_MASK;
> +
> +        rc = -EINVAL;
> +        if ( (mao.pfn != ~0ull) &&
> +             (mao.nr < start_iter ||
> +              ((mao.pfn + mao.nr - 1) < mao.pfn) ||
> +              ((mao.pfn + mao.nr - 1) > domain_get_maximum_gpfn(d))) )
> +            break;
> +
> +        rc = p2m_set_mem_access(d, mao.pfn, mao.nr, start_iter,
> +                                MEMOP_CMD_MASK, mao.access);
> +        if ( rc > 0 )
> +        {
> +            ASSERT(!(rc & MEMOP_CMD_MASK));
> +            rc = hypercall_create_continuation(__HYPERVISOR_memory_op, "lh",
> +                                               cmd | rc, arg);

Either you need to mask cmd properly, or directly use
XENMEM_access_op_set_access.

Jan


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