At 2019-08-16 23:10:31, "Laine Stump" <laine@xxxxxxxxx> wrote:
>The fact that you are modifying this code implies that you are using it,
>and that implies that you are still using legacy KVM device assignment
>(i.e. the pcistub driver) instead of VFIO device assignment. (I say this
>because the function that calls this function you've patched,
>virPCIDeviceReset(), has a check very early on that short-circuits the
>entire function if the device is bound to vfio-pci (and if the device is
>bound to a host driver, then you shouldn't be resetting it anyway, so
>the only reason it would be executed is if you're using legacy KVM
>device assignment or are calling virsh nodedev-reset when you shouldn't).
>
>Legacy PCI device assignment was deprecated over 5 years ago, and was
>removed from the kernel sometime after that. We are seriously
>considering removing all vestigal support for legacy KVM device
>assignment from libvirt, since any kernel that is less than 5 years old
>have VFIO, and most don't even support legacy KVM device assignment at all.
>
>So are you actually using legacy KVM device assignment, or did you just
>find this bug by manual code inspection? If the latter, then you need to
>seriously look into using VFIO instead. If the latter, then this patch
>can safely be pushed, but it's not going to actually do anything (and
>the code it's in will likely no longer exist within the next 6 months).
>
>On 8/15/19 5:44 AM, hexin900110@xxxxxxx wrote:
>> From: hexin <hexin15@xxxxxxxxx>
>>
>> The parent bridge configuration of the current device
>> should be read and reset, instead of reading the current
>> device configuration.
>>
>> Signed-off-by: He Xin <hexin15@xxxxxxxxx>
>> Signed-off-by: Liu Qi <liuqi16@xxxxxxxxx>
>> Signed-off-by: Zhang Yu <zhangyu31@xxxxxxxxx>
>> ---
>> src/util/virpci.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/src/util/virpci.c b/src/util/virpci.c
>> index 61a6b359e5..483de2cb16 100644
>> --- a/src/util/virpci.c
>> +++ b/src/util/virpci.c
>> @@ -821,7 +821,7 @@ virPCIDeviceTrySecondaryBusReset(virPCIDevicePtr dev,
>> /* Read the control register, set the reset flag, wait 200ms,
>> * unset the reset flag and wait 200ms.
>> */
>> - ctl = virPCIDeviceRead16(dev, cfgfd, PCI_BRIDGE_CONTROL);
>> + ctl = virPCIDeviceRead16(dev, parentfd, PCI_BRIDGE_CONTROL);
>>
>> virPCIDeviceWrite16(parent, parentfd, PCI_BRIDGE_CONTROL,
>> ctl | PCI_BRIDGE_CTL_RESET);
>
Thanks for attention. I finded this bug by manual code inspection.
Thanks，
HeXin
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