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[Qemu-devel] [PULL v2 20/40] ivshmem: Leave INTx alone when using MSI-X
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PULL v2 20/40] ivshmem: Leave INTx alone when using MSI-X |
Date: |
Mon, 21 Mar 2016 21:43:43 +0100 |
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 <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
Reviewed-by: Paolo Bonzini <address@hidden>
Message-Id: <address@hidden>
---
hw/misc/ivshmem.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index abcb1c1..65e3a76 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,
--
2.4.3
- [Qemu-devel] [PULL v2 17/40] ivshmem: Failed realize() can leave migration blocker behind, (continued)
- [Qemu-devel] [PULL v2 17/40] ivshmem: Failed realize() can leave migration blocker behind, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 22/40] ivshmem: Simplify rejection of invalid peer ID from server, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 16/40] ivshmem: Fix harmless misuse of Error, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 34/40] qdev: New DEFINE_PROP_ON_OFF_AUTO, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 38/40] ivshmem: Drop ivshmem property x-memdev, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 06/40] tests/libqos/pci-pc: Fix qpci_pc_iomap() to map BARs aligned, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 11/40] ivshmem: Add missing newlines to debug printfs, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 14/40] ivshmem: Drop ivshmem_event() stub, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 15/40] ivshmem: Don't destroy the chardev on version mismatch, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 24/40] ivshmem: Plug leaks on unplug, fix peer disconnect, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 20/40] ivshmem: Leave INTx alone when using MSI-X,
Markus Armbruster <=
- [Qemu-devel] [PULL v2 27/40] ivshmem: Rely on server sending the ID right after the version, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 29/40] ivshmem: Simplify how we cope with short reads from server, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 31/40] ivshmem: Implement shm=... with a memory backend, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 35/40] ivshmem: Replace int role_val by OnOffAuto master, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 01/40] target-ppc: Document TOCTTOU in hugepage support, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 25/40] ivshmem: Receive shared memory synchronously in realize(), Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 10/40] ivshmem: Rewrite specification document, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 39/40] ivshmem: Require master to have ID zero, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 03/40] ivshmem-server: Don't overload POSIX shmem and file name, Markus Armbruster, 2016/03/21
- [Qemu-devel] [PULL v2 19/40] ivshmem: Clean up MSI-X conditions, Markus Armbruster, 2016/03/21