From: Thijs Raymakers Date: Mon, 4 Aug 2025 06:44:05 +0000 (+0200) Subject: KVM: x86: use array_index_nospec with indices that come from guest X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=c87bd4dd43a624109c3cc42d843138378a7f4548;p=users%2Fjedix%2Flinux-maple.git KVM: x86: use array_index_nospec with indices that come from guest min and dest_id are guest-controlled indices. Using array_index_nospec() after the bounds checks clamps these values to mitigate speculative execution side-channels. Signed-off-by: Thijs Raymakers Cc: stable@vger.kernel.org Cc: Sean Christopherson Cc: Paolo Bonzini Cc: Greg Kroah-Hartman Fixes: 715062970f37 ("KVM: X86: Implement PV sched yield hypercall") Fixes: bdf7ffc89922 ("KVM: LAPIC: Fix pv ipis out-of-bounds access") Fixes: 4180bf1b655a ("KVM: X86: Implement "send IPI" hypercall") Link: https://lore.kernel.org/r/20250804064405.4802-1-thijs@raymakers.nl Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 8172c2042dd68..5fc437341e03a 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -810,6 +810,8 @@ static int __pv_send_ipi(unsigned long *ipi_bitmap, struct kvm_apic_map *map, if (min > map->max_apic_id) return 0; + min = array_index_nospec(min, map->max_apic_id + 1); + for_each_set_bit(i, ipi_bitmap, min((u32)BITS_PER_LONG, (map->max_apic_id - min + 1))) { if (map->phys_map[min + i]) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a1c49bc681c46..604490b1cb19c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9908,8 +9908,11 @@ static void kvm_sched_yield(struct kvm_vcpu *vcpu, unsigned long dest_id) rcu_read_lock(); map = rcu_dereference(vcpu->kvm->arch.apic_map); - if (likely(map) && dest_id <= map->max_apic_id && map->phys_map[dest_id]) - target = map->phys_map[dest_id]->vcpu; + if (likely(map) && dest_id <= map->max_apic_id) { + dest_id = array_index_nospec(dest_id, map->max_apic_id + 1); + if (map->phys_map[dest_id]) + target = map->phys_map[dest_id]->vcpu; + } rcu_read_unlock();