67 lines
2.6 KiB
Diff
67 lines
2.6 KiB
Diff
From e34f4d87e8d47b0a65cb663aaf7bef60c2112d36 Mon Sep 17 00:00:00 2001
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From: Igor Mammedov <imammedo@redhat.com>
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Date: Mon, 8 Apr 2024 13:09:56 +0200
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Subject: [PATCH] kvm: error out of kvm_irqchip_add_msi_route() in case of full
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route table
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subj is calling kvm_add_routing_entry() which simply extends
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KVMState::irq_routes::entries[]
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but doesn't check if number of routes goes beyond limit the kernel
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is willing to accept. Which later leads toi the assert
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qemu-kvm: ../accel/kvm/kvm-all.c:1833: kvm_irqchip_commit_routes: Assertion `ret == 0' failed
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typically it happens during guest boot for large enough guest
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Reproduced with:
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./qemu --enable-kvm -m 8G -smp 64 -machine pc \
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`for b in {1..2}; do echo -n "-device pci-bridge,id=pci$b,chassis_nr=$b ";
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for i in {0..31}; do touch /tmp/vblk$b$i;
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echo -n "-drive file=/tmp/vblk$b$i,if=none,id=drive$b$i,format=raw
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-device virtio-blk-pci,drive=drive$b$i,bus=pci$b ";
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done; done`
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While crash at boot time is bad, the same might happen at hotplug time
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which is unacceptable.
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So instead calling kvm_add_routing_entry() unconditionally, check first
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that number of routes won't exceed KVM_CAP_IRQ_ROUTING. This way virtio
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device insteads killin qemu, will gracefully fail to initialize device
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as expected with following warnings on console:
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virtio-blk failed to set guest notifier (-28), ensure -accel kvm is set.
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virtio_bus_start_ioeventfd: failed. Fallback to userspace (slower).
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Signed-off-by: Igor Mammedov <imammedo@redhat.com>
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Message-ID: <20240408110956.451558-1-imammedo@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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---
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accel/kvm/kvm-all.c | 15 ++++++++++-----
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1 file changed, 10 insertions(+), 5 deletions(-)
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diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
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index a8cecd040ebc..931f74256e8a 100644
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--- a/accel/kvm/kvm-all.c
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+++ b/accel/kvm/kvm-all.c
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@@ -1999,12 +1999,17 @@ int kvm_irqchip_add_msi_route(KVMRouteChange *c, int vector, PCIDevice *dev)
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return -EINVAL;
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}
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- trace_kvm_irqchip_add_msi_route(dev ? dev->name : (char *)"N/A",
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- vector, virq);
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+ if (s->irq_routes->nr < s->gsi_count) {
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+ trace_kvm_irqchip_add_msi_route(dev ? dev->name : (char *)"N/A",
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+ vector, virq);
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- kvm_add_routing_entry(s, &kroute);
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- kvm_arch_add_msi_route_post(&kroute, vector, dev);
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- c->changes++;
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+ kvm_add_routing_entry(s, &kroute);
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+ kvm_arch_add_msi_route_post(&kroute, vector, dev);
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+ c->changes++;
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+ } else {
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+ kvm_irqchip_release_virq(s, virq);
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+ return -ENOSPC;
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+ }
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return virq;
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}
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