[Xen-devel] RE: [PATCH] Enable PCI passthrough with stub domain.

["Li, Xin" <xin.li@xxxxxxxxx>]

Keir, are you suggesting to have pcifront in stub domain?
-Xin

>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Keir Fraser
>Sent: Friday, January 09, 2009 7:30 PM
>To: Shohei Fujiwara; xen-devel@xxxxxxxxxxxxxxxxxxx
>Subject: [Xen-devel] Re: [PATCH] Enable PCI passthrough with stub domain.
>
>One major point of stubdomains is to deprivilege qemu. If we give it access
>to domctls like {memory,ioport}_mapping it's rather defeating that purpose.
>Perhaps some thought is needed as to how PCI passthru is architected -- the
>actual setting up of access permissions (which is implicitly what some of
>those domctls do) should be done by the toolstack and/or pciback, both of
>which continue to reside in dom0.
>
> -- Keir
>
>On 09/01/2009 10:08, "Shohei Fujiwara" <fujiwara-sxa@xxxxxxxxxxxxxxx> wrote:
>
>> This patch enables PCI passthrough with stub domain.
>>
>> PCI passthrough with stub domain has failed in the past.
>> The primary reason is that hypercalls from qemu in stub domain are rejected.
>>
>> This patch allows qemu in stub domain to call the hypercalls which is
>> needed for PCI passthrough. For security, if target domain of
>> hypercall is different from that of stub domain, it rejects hypercall.
>>
>> To use PCI passthrough, please configure pciback driver to be
>> permissive, because qemu has own virtualization code for PCI
>> passthrough. For example:
>>
>>     # cd /sys/bus/pci/drivers/pciback
>>     # echo "0000:0d:00.0" > permissive
>>
>> Currently Linux guest only works.
>> But Windows guest doesn't work, so I'm debugging for now.
>> I hope this patch will be useful for other developers in community.
>>
>> Thanks,
>> --
>> Shohei Fujiwara.
>>
>>
>> Signed-off-by: Shohei Fujiwara <fujiwara-sxa@xxxxxxxxxxxxxxx>
>>
>> diff -r b9721b2766c1 xen/arch/x86/irq.c
>> --- a/xen/arch/x86/irq.c Wed Jan 07 11:25:00 2009 +0000
>> +++ b/xen/arch/x86/irq.c Thu Jan 08 18:58:36 2009 +0900
>> @@ -857,7 +857,7 @@ int map_domain_pirq(
>>      if ( type == MAP_PIRQ_TYPE_MSI )
>>          return -EINVAL;
>>
>> -    if ( !IS_PRIV(current->domain) )
>> +    if ( !IS_PRIV_FOR(current->domain, d) )
>>          return -EPERM;
>>
>>      if ( pirq < 0 || pirq >= NR_IRQS || vector < 0 || vector >= NR_VECTORS )
>> @@ -931,7 +931,7 @@ int unmap_domain_pirq(struct domain *d,
>>      if ( (pirq < 0) || (pirq >= NR_IRQS) )
>>          return -EINVAL;
>>
>> -    if ( !IS_PRIV(current->domain) )
>> +    if ( !IS_PRIV_FOR(current->domain, d) )
>>          return -EINVAL;
>>
>>      ASSERT(spin_is_locked(&pcidevs_lock));
>> diff -r b9721b2766c1 xen/arch/x86/physdev.c
>> --- a/xen/arch/x86/physdev.c Wed Jan 07 11:25:00 2009 +0000
>> +++ b/xen/arch/x86/physdev.c Thu Jan 08 18:58:36 2009 +0900
>> @@ -34,9 +34,6 @@ static int physdev_map_pirq(struct physd
>>      struct msi_info _msi;
>>      void *map_data = NULL;
>>
>> -    if ( !IS_PRIV(current->domain) )
>> -        return -EPERM;
>> -
>>      if ( !map )
>>          return -EINVAL;
>>
>> @@ -49,6 +46,14 @@ static int physdev_map_pirq(struct physd
>>      {
>>          ret = -ESRCH;
>>          goto free_domain;
>> +    }
>> +    else
>> +    {
>> +        if ( !IS_PRIV_FOR(current->domain, d) )
>> +        {
>> +            ret = -EPERM;
>> +            goto free_domain;
>> +        }
>>      }
>>
>>      /* Verify or get vector. */
>> @@ -161,8 +166,8 @@ static int physdev_unmap_pirq(struct phy
>>      struct domain *d;
>>      int ret;
>>
>> -    if ( !IS_PRIV(current->domain) )
>> -        return -EPERM;
>> +    if ( !unmap )
>> +        return -EINVAL;
>>
>>      if ( unmap->domid == DOMID_SELF )
>>          d = rcu_lock_domain(current->domain);
>> @@ -171,6 +176,14 @@ static int physdev_unmap_pirq(struct phy
>>
>>      if ( d == NULL )
>>          return -ESRCH;
>> +    else
>> +    {
>> +        if ( !IS_PRIV_FOR(current->domain, d) )
>> +        {
>> +            rcu_unlock_domain(d);
>> +            return -EPERM;
>> +        }
>> +    }
>>
>>      spin_lock(&pcidevs_lock);
>>      spin_lock(&d->event_lock);
>> diff -r b9721b2766c1 xen/common/domctl.c
>> --- a/xen/common/domctl.c Wed Jan 07 11:25:00 2009 +0000
>> +++ b/xen/common/domctl.c Thu Jan 08 18:58:36 2009 +0900
>> @@ -193,14 +193,49 @@ long do_domctl(XEN_GUEST_HANDLE(xen_domc
>>      long ret = 0;
>>      struct xen_domctl curop, *op = &curop;
>>
>> -    if ( !IS_PRIV(current->domain) )
>> -        return -EPERM;
>> -
>>      if ( copy_from_guest(op, u_domctl, 1) )
>>          return -EFAULT;
>>
>>      if ( op->interface_version != XEN_DOMCTL_INTERFACE_VERSION )
>>          return -EACCES;
>> +
>> +    switch ( op->cmd )
>> +    {
>> +    case XEN_DOMCTL_pin_mem_cacheattr:
>> +    case XEN_DOMCTL_memory_mapping:
>> +    case XEN_DOMCTL_ioport_mapping:
>> +    case XEN_DOMCTL_assign_device:
>> +    case XEN_DOMCTL_deassign_device:
>> +    case XEN_DOMCTL_bind_pt_irq:
>> +    case XEN_DOMCTL_unbind_pt_irq:
>> +    {
>> +        struct domain *d;
>> +
>> +        if ( op->domain != DOMID_SELF )
>> +        {
>> +            d = rcu_lock_domain_by_id(op->domain);
>> +
>> +            if ( d == NULL )
>> +                return -ESRCH;
>> +            else
>> +            {
>> +                if ( !IS_PRIV_FOR(current->domain, d) )
>> +                {
>> +                    rcu_unlock_domain(d);
>> +                    return -EPERM;
>> +                }
>> +                else
>> +                    rcu_unlock_domain(d);
>> +            }
>> +            break;
>> +        }
>> +    }
>> +
>> +    default:
>> +        if ( !IS_PRIV(current->domain) )
>> +            return -EPERM;
>> +        break;
>> +    }
>>
>>      spin_lock(&domctl_lock);
>>
>
>
>
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