[Qemu-devel] migrating guest with msi-x interrupts

[Cam Macdonell]

Hi,

I'm trying to migrate a guest device with MSI-X interrupts.  However,
the interrupts are not injected into the guest.  I've added some
tracing to msix.c and it seems that the MSI-X vectors are masked when
the guest is resumed (I'm testing with static migration).

In particular, in msix.c, msix_is_masked(...) is returning true when
the guest resumes which causes msix_set_pending() to be called instead
of msix_set_irq().

/* Send an MSI-X message */
void msix_notify(PCIDevice *dev, unsigned vector)
{
    uint8_t *table_entry = dev->msix_table_page + vector * MSIX_ENTRY_SIZE;
    uint64_t address;
    uint32_t data;

    if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
        return;

    if (msix_is_masked(dev, vector)) {
        msix_set_pending(dev, vector);
        return;
    }

...

Does migrating a guest device that uses MSI-X require
msix_load()/save() to be called explicity in a pre/post_save/load
function?

Any pointers or comments would be helpful,
Cam