On Mon, Jun 23, 2025, David Woodhouse wrote: > On Mon, 2025-05-12 at 10:29 +0100, Paul Durrant wrote: > > On 08/05/2025 21:30, David Woodhouse wrote: > > > From: David Woodhouse <dwmw@xxxxxxxxxxxx> > > > > > > To avoid imposing an ordering constraint on userspace, allow 'invalid' > > > event channel targets to be configured in the IRQ routing table. > > > > > > This is the same as accepting interrupts targeted at vCPUs which don't > > > exist yet, which is already the case for both Xen event channels *and* > > > for MSIs (which don't do any filtering of permitted APIC ID targets at > > > all). > > > > > > If userspace actually *triggers* an IRQ with an invalid target, that > > > will fail cleanly, as kvm_xen_set_evtchn_fast() also does the same range > > > check. > > > > > > If KVM enforced that the IRQ target must be valid at the time it is > > > *configured*, that would force userspace to create all vCPUs and do > > > various other parts of setup (in this case, setting the Xen long_mode) > > > before restoring the IRQ table. > > > > > > Cc: stable@xxxxxxxxxxxxxxx > > > Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> > > > --- > > > arch/x86/kvm/xen.c | 14 ++++++++++++-- > > > 1 file changed, 12 insertions(+), 2 deletions(-) > > > > > > > Reviewed-by: Paul Durrant <paul@xxxxxxx> > > Ping? Almost there :-) I've got it applied (for 6.16), just need to run my generic test stuff before making it "official".
