From: Yi Wang wang.yi59@zte.com.cn
commit a80ced6ea514000d34bf1239d47553de0d1ee89e upstream.
As guest_irq is coming from KVM_IRQFD API call, it may trigger crash in svm_update_pi_irte() due to out-of-bounds:
crash> bt PID: 22218 TASK: ffff951a6ad74980 CPU: 73 COMMAND: "vcpu8" #0 [ffffb1ba6707fa40] machine_kexec at ffffffff8565b397 #1 [ffffb1ba6707fa90] __crash_kexec at ffffffff85788a6d #2 [ffffb1ba6707fb58] crash_kexec at ffffffff8578995d #3 [ffffb1ba6707fb70] oops_end at ffffffff85623c0d #4 [ffffb1ba6707fb90] no_context at ffffffff856692c9 #5 [ffffb1ba6707fbf8] exc_page_fault at ffffffff85f95b51 #6 [ffffb1ba6707fc50] asm_exc_page_fault at ffffffff86000ace [exception RIP: svm_update_pi_irte+227] RIP: ffffffffc0761b53 RSP: ffffb1ba6707fd08 RFLAGS: 00010086 RAX: ffffb1ba6707fd78 RBX: ffffb1ba66d91000 RCX: 0000000000000001 RDX: 00003c803f63f1c0 RSI: 000000000000019a RDI: ffffb1ba66db2ab8 RBP: 000000000000019a R8: 0000000000000040 R9: ffff94ca41b82200 R10: ffffffffffffffcf R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffffffffffcf R15: 000000000000005f ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffffb1ba6707fdb8] kvm_irq_routing_update at ffffffffc09f19a1 [kvm] #8 [ffffb1ba6707fde0] kvm_set_irq_routing at ffffffffc09f2133 [kvm] #9 [ffffb1ba6707fe18] kvm_vm_ioctl at ffffffffc09ef544 [kvm] RIP: 00007f143c36488b RSP: 00007f143a4e04b8 RFLAGS: 00000246 RAX: ffffffffffffffda RBX: 00007f05780041d0 RCX: 00007f143c36488b RDX: 00007f05780041d0 RSI: 000000004008ae6a RDI: 0000000000000020 RBP: 00000000000004e8 R8: 0000000000000008 R9: 00007f05780041e0 R10: 00007f0578004560 R11: 0000000000000246 R12: 00000000000004e0 R13: 000000000000001a R14: 00007f1424001c60 R15: 00007f0578003bc0 ORIG_RAX: 0000000000000010 CS: 0033 SS: 002b
Vmx have been fix this in commit 3a8b0677fc61 (KVM: VMX: Do not BUG() on out-of-bounds guest IRQ), so we can just copy source from that to fix this.
Co-developed-by: Yi Liu liu.yi24@zte.com.cn Signed-off-by: Yi Liu liu.yi24@zte.com.cn Signed-off-by: Yi Wang wang.yi59@zte.com.cn Message-Id: 20220309113025.44469-1-wang.yi59@zte.com.cn Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/avic.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -799,7 +799,7 @@ int svm_update_pi_irte(struct kvm *kvm, { struct kvm_kernel_irq_routing_entry *e; struct kvm_irq_routing_table *irq_rt; - int idx, ret = -EINVAL; + int idx, ret = 0;
if (!kvm_arch_has_assigned_device(kvm) || !irq_remapping_cap(IRQ_POSTING_CAP)) @@ -810,7 +810,13 @@ int svm_update_pi_irte(struct kvm *kvm,
idx = srcu_read_lock(&kvm->irq_srcu); irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); - WARN_ON(guest_irq >= irq_rt->nr_rt_entries); + + if (guest_irq >= irq_rt->nr_rt_entries || + hlist_empty(&irq_rt->map[guest_irq])) { + pr_warn_once("no route for guest_irq %u/%u (broken user space?)\n", + guest_irq, irq_rt->nr_rt_entries); + goto out; + }
hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) { struct vcpu_data vcpu_info;