From fd563564222f308e1d86847efdec8555fb472536 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Tue, 9 May 2017 14:00:44 +0800 Subject: [PATCH] kvm: irqchip: skip update msi when disabled It's possible that one device kept its irqfd/virq there even when MSI/MSIX was disabled globally for that device. One example is virtio-net-pci (see commit f1d0f15a6 and virtio_pci_vq_vector_mask()). It is used as a fast path to avoid allocate/release irqfd/virq frequently when guest enables/disables MSIX. However, this fast path brought a problem to msi_route_list, that the device MSIRouteEntry is still dangling there even if MSIX disabled - then we cannot know which message to fetch, even if we can, the messages are meaningless. In this case, we can just simply ignore this entry. It's safe, since when MSIX is enabled again, we'll rebuild them no matter what. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1448813 Signed-off-by: Peter Xu Message-Id: <1494309644-18743-4-git-send-email-peterx@redhat.com> Signed-off-by: Paolo Bonzini --- target/i386/kvm.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 49b6115eae..9087677d00 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -43,6 +43,7 @@ #include "standard-headers/asm-x86/hyperv.h" #include "hw/pci/pci.h" #include "hw/pci/msi.h" +#include "hw/pci/msix.h" #include "migration/blocker.h" #include "exec/memattrs.h" #include "trace.h" @@ -3510,12 +3511,17 @@ static void kvm_update_msi_routes_all(void *private, bool global, int cnt = 0; MSIRouteEntry *entry; MSIMessage msg; + PCIDevice *dev; + /* TODO: explicit route update */ QLIST_FOREACH(entry, &msi_route_list, list) { cnt++; - msg = pci_get_msi_message(entry->dev, entry->vector); - kvm_irqchip_update_msi_route(kvm_state, entry->virq, - msg, entry->dev); + dev = entry->dev; + if (!msix_enabled(dev) && !msi_enabled(dev)) { + continue; + } + msg = pci_get_msi_message(dev, entry->vector); + kvm_irqchip_update_msi_route(kvm_state, entry->virq, msg, dev); } kvm_irqchip_commit_routes(kvm_state); trace_kvm_x86_update_msi_routes(cnt);