From c87bd4dd43a624109c3cc42d843138378a7f4548 Mon Sep 17 00:00:00 2001 From: Thijs Raymakers Date: Mon, 4 Aug 2025 08:44:05 +0200 Subject: 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 --- arch/x86/kvm/x86.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a1c49bc681c4..604490b1cb19 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(); -- cgit v1.2.3