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Re: [PATCH] hw/pci/pci.c: Assert that pci_irq_handler() inputs are valid
From: |
Isaku Yamahata |
Subject: |
Re: [PATCH] hw/pci/pci.c: Assert that pci_irq_handler() inputs are valid |
Date: |
Wed, 24 Mar 2021 09:21:30 -0700 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
I included (mostly) same patch into my patch series just for patch
completeness.
Please choose whichever you like.
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
On Tue, Mar 23, 2021 at 04:46:01PM +0000,
Peter Maydell <peter.maydell@linaro.org> wrote:
> pci_irq_handler documents that it must be called with 0 <= irq_num <=
> 3 and level either 0 or 1. Add assertions that the caller has passed
> us in valid arguments.
>
> In particular, if a device model fails to set the PCI_INTERRUPT_PIN
> field in its config space correctly to indicate that it has an
> interrupt, and then tries to raise an interrupt (either by calling
> pci_set_irq(), or by getting a qemu_irq from pci_allocate_irq() and
> then calling qemu_set_irq() on that) we will now diagnose this device
> model bug with an assertion rather than engaging in the undefined
> behaviour of shifting by a negative number.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> hw/pci/pci.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 0eadcdbc9ec..38aefe22ab3 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1449,6 +1449,9 @@ static void pci_irq_handler(void *opaque, int irq_num,
> int level)
> PCIDevice *pci_dev = opaque;
> int change;
>
> + assert(irq_num >= 0 && irq_num < PCI_NUM_PINS);
> + assert(level == 0 || level == 1);
> +
> change = level - pci_irq_state(pci_dev, irq_num);
> if (!change)
> return;
> --
> 2.20.1
>
>
--
Isaku Yamahata <isaku.yamahata@gmail.com>