On Sun, Aug 03, 2014 at 10:51:08AM +0300, Amir Vadai wrote: >On 8/1/2014 7:54 AM, Gavin Shan wrote: >> The VFIO driver is routing LSI interrupts by capturing, masking, >> and then delivering. When passing though Mallanox adapters from >> host to guest, interrupt storm was reported from host and guest. >> That's because we can't mask the LSI interrupt with help of PCI >> command register. >Hi Gavin, > >What is the problem with masking the interrupts with the PCI command >register? I'm asking because I want to understand in which devices we >have the problem, and if it could be fixed by firmware guys. >What are the implications of having the quirk? > The way to mask the interrupt through PCI command register isn't taking effect on IBM power platform. So we have to have the quirk so that the interrupt could be masked from interrupt controller side with function disable_irq_nosync(). If the interrupt can't be masked properly, we detect interrupt storm reported from host/guest when passing through those devices via VFIO without suprise. >> >> [root@ncc-1701 ~]# lspci | grep Mellanox >> 0001:05:00.0 Ethernet controller: Mellanox Technologies MT27500 \ >> Family [ConnectX-3] >> 0005:01:00.0 Ethernet controller: Mellanox Technologies MT26448 \ >> [ConnectX EN 10GigE, PCIe 2.0 5GT/s] (rev b0) >> >> The patch marks broken INTx masking for Mellanox devices so that >> the VFIO driver will always mask the interrupt from interrupt >> controller side to avoid interrupt storm. >> >> Cc: Amir Vadai <amirv@xxxxxxxxxxxx> >> Suggested-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> >> Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> >> --- >> drivers/pci/quirks.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c >> index d0f6926..8c2b96f 100644 >> --- a/drivers/pci/quirks.c >> +++ b/drivers/pci/quirks.c >> @@ -2977,6 +2977,10 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CHELSIO, 0x0030, >> quirk_broken_intx_masking); >> DECLARE_PCI_FIXUP_HEADER(0x1814, 0x0601, /* Ralink RT2800 802.11n PCI */ >> quirk_broken_intx_masking); >> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0x1003, >> + quirk_broken_intx_masking); >> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0x6750, >> + quirk_broken_intx_masking); >I still don't understand what exactly is the problem, but I assume that >there are other Mellanox devices that suffer from it. > Yeah, that's possible. I didn't have chance to test other Mellanox devices except the above two. >> /* >> * Realtek RTL8169 PCI Gigabit Ethernet Controller (rev 10) >> * Subsystem: Realtek RTL8169/8110 Family PCI Gigabit Ethernet NIC >> > >Thanks, >Amir > Thanks, Gavin -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
