On 01/22/2010 04:16 AM, Daniel Veillard wrote:
> On Thu, Jan 21, 2010 at 11:33:21AM -0500, Chris Lalancette wrote:
>> The patches to add ACS checking to PCI device passthrough
>> introduced a bug. With the current code, if you try to
>> passthrough a device on the root bus (i.e. bus 0), then
>> it denies the passthrough. This is because the code in
>> pciDeviceIsBehindSwitchLackingACS() to check for a parent
>> device doesn't take into account the possibility of the
>> root bus. If we are on the root bus, it means we
>> legitimately can't find a parent, and it also means that
>> we don't have to worry about whether ACS is enabled.
>> Therefore return 0 (indicating we don't lack ACS) from
>> pciDeviceIsBehindSwitchLackingACS().
>>
>> Signed-off-by: Chris Lalancette <clalance@xxxxxxxxxx>
>> ---
>> src/util/pci.c | 19 ++++++++++++++-----
>> 1 files changed, 14 insertions(+), 5 deletions(-)
>>
>> diff --git a/src/util/pci.c b/src/util/pci.c
>> index 086b751..0defbfe 100644
>> --- a/src/util/pci.c
>> +++ b/src/util/pci.c
>> @@ -1198,11 +1198,20 @@ pciDeviceIsBehindSwitchLackingACS(virConnectPtr conn,
>> {
>> pciDevice *parent;
>>
>> - if (!(parent = pciGetParentDevice(conn, dev))) {
>> - pciReportError(conn, VIR_ERR_NO_SUPPORT,
>> - _("Failed to find parent device for %s"),
>> - dev->name);
>> - return -1;
>> + parent = pciGetParentDevice(conn, dev);
>> + if (!parent) {
>> + /* if we have no parent, and this is the root bus, ACS doesn't come
>> + * into play since devices on the root bus can't P2P without going
>> + * through the root IOMMU.
>> + */
>> + if (dev->bus == 0)
>> + return 0;
>> + else {
>> + pciReportError(conn, VIR_ERR_NO_SUPPORT,
>> + _("Failed to find parent device for %s"),
>> + dev->name);
>> + return -1;
>> + }
>> }
>>
>> /* XXX we should rather fail when we can't find device's parent and
>
> ACK,
Thanks, pushed.
--
Chris Lalancette
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