On Fri, May 26, 2023, Sean Christopherson wrote: > From: Michal Luczaj <mhal@xxxxxxx> > > Keep switching between LAPIC_MODE_X2APIC and LAPIC_MODE_DISABLED during > APIC map construction to hunt for TOCTOU bugs in KVM. KVM's optimized map > recalc makes multiple passes over the list of vCPUs, and the calculations > ignore vCPU's whose APIC is hardware-disabled, i.e. there's a window where > toggling LAPIC_MODE_DISABLED is quite interesting. > > Signed-off-by: Michal Luczaj <mhal@xxxxxxx> > Co-developed-by: Sean Christopherson <seanjc@xxxxxxxxxx> > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > --- > tools/testing/selftests/kvm/Makefile | 1 + > .../kvm/x86_64/recalc_apic_map_race.c | 76 +++++++++++++++++++ > 2 files changed, 77 insertions(+) > create mode 100644 tools/testing/selftests/kvm/x86_64/recalc_apic_map_race.c Since there's another bug+test related to kvm_recalculate_apic_map()[*], I think it makes sense to name this recalc_apic_map_test, and then fold the LDR test into this one. The LDR test is tiny enough that I don't think it's worth a separate binary, even though I generally prefer to keep the selftests small.
