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| author | Thijs Raymakers <thijs@raymakers.nl> | 2025-08-04 08:44:05 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-09-04 14:41:43 +0200 |
| commit | 31a0ad2f60cb4816e06218b63e695eb72ce74974 (patch) | |
| tree | 9d71125184d6868c0a46e3badfd05ed270b99587 | |
| parent | 794399019301944fd6d2e0d7a51b3327e26c410e (diff) | |
| download | linux-31a0ad2f60cb4816e06218b63e695eb72ce74974.tar.gz linux-31a0ad2f60cb4816e06218b63e695eb72ce74974.tar.bz2 linux-31a0ad2f60cb4816e06218b63e695eb72ce74974.zip | |
KVM: x86: use array_index_nospec with indices that come from guest
commit c87bd4dd43a624109c3cc42d843138378a7f4548 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 a40408895e23..fdbca15ecb44 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -610,6 +610,8 @@ 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 b61f697479a3..63df6c33e3a4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8359,8 +8359,11 @@ static void kvm_sched_yield(struct kvm *kvm, unsigned long dest_id) rcu_read_lock(); map = rcu_dereference(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(); |