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?
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