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authorMarkus Armbruster <armbru@redhat.com>2016-03-15 19:34:35 +0100
committerMarkus Armbruster <armbru@redhat.com>2016-03-21 21:29:01 +0100
commit2d1d422d1145085fdde6a90d70cbbff7103d469b (patch)
tree19b2ea6f6c5a81069c126504187ae1199281820f
parent082751e82bed9482fc75863e0b305949bb230c6a (diff)
ivshmem: Leave INTx alone when using MSI-X
The ivshmem device can either use MSI-X or legacy INTx for interrupts. With MSI-X enabled, peer interrupt events trigger an MSI as they should. But software can still raise INTx via interrupt status and mask register in BAR 0. This is explicitly prohibited by PCI Local Bus Specification Revision 3.0, section 6.8.3.3: While enabled for MSI or MSI-X operation, a function is prohibited from using its INTx# pin (if implemented) to request service (MSI, MSI-X, and INTx# are mutually exclusive). Fix the device model to leave INTx alone when using MSI-X. Document that we claim to use INTx in config space even when we don't. Unlike other devices, ivshmem does *not* use INTx when configured for MSI-X and MSI-X isn't enabled by software. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1458066895-20632-21-git-send-email-armbru@redhat.com>
-rw-r--r--hw/misc/ivshmem.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index abcb1c1bfe..65e3a76870 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -126,6 +126,11 @@ static void ivshmem_update_irq(IVShmemState *s)
PCIDevice *d = PCI_DEVICE(s);
uint32_t isr = s->intrstatus & s->intrmask;
+ /* No INTx with msi=on, whether the guest enabled MSI-X or not */
+ if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
+ return;
+ }
+
/* don't print ISR resets */
if (isr) {
IVSHMEM_DPRINTF("Set IRQ to %d (%04x %04x)\n",
@@ -873,6 +878,10 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp)
pci_conf = dev->config;
pci_conf[PCI_COMMAND] = PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
+ /*
+ * Note: we don't use INTx with IVSHMEM_MSI at all, so this is a
+ * bald-faced lie then. But it's a backwards compatible lie.
+ */
pci_config_set_interrupt_pin(pci_conf, 1);
memory_region_init_io(&s->ivshmem_mmio, OBJECT(s), &ivshmem_mmio_ops, s,