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authorJakub Kicinski <kuba@kernel.org>2025-07-10 10:08:47 -0700
committerJakub Kicinski <kuba@kernel.org>2025-07-10 10:10:49 -0700
commit3321e97eab71df7d632b35276da9f8503e6e040f (patch)
tree6a4ec5e7556d99a0ff25f4035f078d8e0186f359 /arch/x86/kvm/xen.c
parentMerge branch 'net-dsa-rzn1_a5psw-add-compile_test' (diff)
parentMerge tag 'net-6.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net (diff)
downloadlinux-rng-3321e97eab71df7d632b35276da9f8503e6e040f.tar.xz
linux-rng-3321e97eab71df7d632b35276da9f8503e6e040f.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.16-rc6). No conflicts. Adjacent changes: Documentation/devicetree/bindings/net/allwinner,sun8i-a83t-emac.yaml 0a12c435a1d6 ("dt-bindings: net: sun8i-emac: Add A100 EMAC compatible") b3603c0466a8 ("dt-bindings: net: sun8i-emac: Rename A523 EMAC0 to GMAC0") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'arch/x86/kvm/xen.c')
-rw-r--r--arch/x86/kvm/xen.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 9b029bb29a16..5fa2cca43653 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -1971,8 +1971,19 @@ int kvm_xen_setup_evtchn(struct kvm *kvm,
{
struct kvm_vcpu *vcpu;
- if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
- return -EINVAL;
+ /*
+ * Don't check for the port being within range of max_evtchn_port().
+ * Userspace can configure what ever targets it likes; events just won't
+ * be delivered if/while the target is invalid, just like userspace can
+ * configure MSIs which target non-existent APICs.
+ *
+ * This allow on Live Migration and Live Update, the IRQ routing table
+ * can be restored *independently* of other things like creating vCPUs,
+ * without imposing an ordering dependency on userspace. In this
+ * particular case, the problematic ordering would be with setting the
+ * Xen 'long mode' flag, which changes max_evtchn_port() to allow 4096
+ * instead of 1024 event channels.
+ */
/* We only support 2 level event channels for now */
if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)