Re: [Qemu-devel] [PATCH v2] ioapic: use irq number instead of vector in ioapic_eoi_broadcast

[Li Qiang <liq3ea@gmail.com>]

Ping, what's the status of this patch.


Li Qiang <liq3ea@163.com> 于2019年6月22日周六 上午8:21写道：

> When emulating irqchip in qemu, such as following command:
>
> x86_64-softmmu/qemu-system-x86_64 -m 1024 -smp 4 -hda /home/test/test.img
> -machine kernel-irqchip=off --enable-kvm -vnc :0 -device edu -monitor stdio
>
> We will get a crash with following asan output:
>
> (qemu) /home/test/qemu5/qemu/hw/intc/ioapic.c:266:27: runtime error: index
> 35 out of bounds for type 'int [24]'
> =================================================================
> ==113504==ERROR: AddressSanitizer: heap-buffer-overflow on address
> 0x61b000003114 at pc 0x5579e3c7a80f bp 0x7fd004bf8c10 sp 0x7fd004bf8c00
> WRITE of size 4 at 0x61b000003114 thread T4
>     #0 0x5579e3c7a80e in ioapic_eoi_broadcast
> /home/test/qemu5/qemu/hw/intc/ioapic.c:266
>     #1 0x5579e3c6f480 in apic_eoi /home/test/qemu5/qemu/hw/intc/apic.c:428
>     #2 0x5579e3c720a7 in apic_mem_write
> /home/test/qemu5/qemu/hw/intc/apic.c:802
>     #3 0x5579e3b1e31a in memory_region_write_accessor
> /home/test/qemu5/qemu/memory.c:503
>     #4 0x5579e3b1e6a2 in access_with_adjusted_size
> /home/test/qemu5/qemu/memory.c:569
>     #5 0x5579e3b28d77 in memory_region_dispatch_write
> /home/test/qemu5/qemu/memory.c:1497
>     #6 0x5579e3a1b36b in flatview_write_continue
> /home/test/qemu5/qemu/exec.c:3323
>     #7 0x5579e3a1b633 in flatview_write /home/test/qemu5/qemu/exec.c:3362
>     #8 0x5579e3a1bcb1 in address_space_write
> /home/test/qemu5/qemu/exec.c:3452
>     #9 0x5579e3a1bd03 in address_space_rw /home/test/qemu5/qemu/exec.c:3463
>     #10 0x5579e3b8b979 in kvm_cpu_exec
> /home/test/qemu5/qemu/accel/kvm/kvm-all.c:2045
>     #11 0x5579e3ae4499 in qemu_kvm_cpu_thread_fn
> /home/test/qemu5/qemu/cpus.c:1287
>     #12 0x5579e4cbdb9f in qemu_thread_start util/qemu-thread-posix.c:502
>     #13 0x7fd0146376da in start_thread
> (/lib/x86_64-linux-gnu/libpthread.so.0+0x76da)
>     #14 0x7fd01436088e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x12188e
>
> This is because in ioapic_eoi_broadcast function, we uses 'vector' to
> index the 's->irq_eoi'. To fix this, we should uses the irq number.
>
> Signed-off-by: Li Qiang <liq3ea@163.com>
> ---
> Change since v1:
> remove auto-generated unnecessary message
>
>  hw/intc/ioapic.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
> index 7074489fdf..711775cc6f 100644
> --- a/hw/intc/ioapic.c
> +++ b/hw/intc/ioapic.c
> @@ -245,8 +245,8 @@ void ioapic_eoi_broadcast(int vector)
>              s->ioredtbl[n] = entry & ~IOAPIC_LVT_REMOTE_IRR;
>
>              if (!(entry & IOAPIC_LVT_MASKED) && (s->irr & (1 << n))) {
> -                ++s->irq_eoi[vector];
> -                if (s->irq_eoi[vector] >= SUCCESSIVE_IRQ_MAX_COUNT) {
> +                ++s->irq_eoi[n];
> +                if (s->irq_eoi[n] >= SUCCESSIVE_IRQ_MAX_COUNT) {
>                      /*
>                       * Real hardware does not deliver the interrupt
> immediately
>                       * during eoi broadcast, and this lets a buggy guest
> make
> @@ -254,16 +254,16 @@ void ioapic_eoi_broadcast(int vector)
>                       * level-triggered interrupt. Emulate this behavior
> if we
>                       * detect an interrupt storm.
>                       */
> -                    s->irq_eoi[vector] = 0;
> +                    s->irq_eoi[n] = 0;
>                      timer_mod_anticipate(s->delayed_ioapic_service_timer,
>
> qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
>                                           NANOSECONDS_PER_SECOND / 100);
> -                    trace_ioapic_eoi_delayed_reassert(vector);
> +                    trace_ioapic_eoi_delayed_reassert(n);
>                  } else {
>                      ioapic_service(s);
>                  }
>              } else {
> -                s->irq_eoi[vector] = 0;
> +                s->irq_eoi[n] = 0;
>              }
>          }
>      }
> --
> 2.17.1
>
>
>