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| author |   Thijs Raymakers <thijs@raymakers.nl> | 2025-08-04 08:44:05 +0200 |
|---|---|---|
| committer |   Sean Christopherson <seanjc@google.com> | 2025-08-15 11:33:21 -0700 |
| commit | c87bd4dd43a624109c3cc42d843138378a7f4548 (patch) | |
| tree | d1df52ed1c6250367f64d5c87a5498cb97e77369 | |
| parent | Linux 6.17-rc1 (diff) | |
| download | wireguard-linux-c87bd4dd43a624109c3cc42d843138378a7f4548.tar.xz wireguard-linux-c87bd4dd43a624109c3cc42d843138378a7f4548.zip | |
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 <thijs@raymakers.nl>
Cc: stable@vger.kernel.org
Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/lapic.c | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
2 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 8172c2042dd6..5fc437341e03 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 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(); |