On Tue, 2016-01-26 at 09:34 +0800, Jianzhong,Chang wrote: > There are some problems when msi guest_masked is set to 1 by default. > When guest os is windows 2008 r2 server, > the device(eg X540-AT2 vf) is not initialized correctly. > Host will always receive message like this :"VF Reset msg received from vf". > Guest has network connectivity issues, > and can not correctly receive/send the packet.
In other words "the guest doesn't get any interrupts from the NIC". > So, guest_masked is set to 0 by default. This seems consistent with the PCI spec, which says that "After reset, the state of all implemented Mask and Pending bits is 0 (no vectors are masked and no messages are pending)." That's what we *used* to have in Xen, before these commits changed it to assume that IRQs were guest-masked by default: https://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=ad28e42bd1d28d746988ed71654e8aa670629753 https://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=84d6add5593d865736831d150da7c38588f669f6 > --- a/xen/arch/x86/msi.c > +++ b/xen/arch/x86/msi.c > @@ -512,7 +512,7 @@ void guest_mask_msi_irq(struct irq_desc *desc, bool_t > mask) > > static unsigned int startup_msi_irq(struct irq_desc *desc) > { > - if ( unlikely(!msi_set_mask_bit(desc, 0, !!(desc->status & IRQ_GUEST))) ) > + if ( unlikely(!msi_set_mask_bit(desc, 0, 0) )) > WARN(); > return 0; > } In testing, this part actually seems to make the difference in practice. Interrupts now work, and Windows guests have connectivity again. > @@ -972,7 +972,7 @@ static int msix_capability_init(struct pci_dev *dev, > entry->msi_attrib.entry_nr = msi->entry_nr; > entry->msi_attrib.maskbit = 1; > entry->msi_attrib.host_masked = 1; > - entry->msi_attrib.guest_masked = 1; > + entry->msi_attrib.guest_masked = 0; > entry->msi_attrib.pos = pos; > entry->irq = msi->irq; > entry->dev = dev; That also seems correct though, since it reflects the actual state we intend to emulate.
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