From: "Michael S. Tsirkin" <mst@redhat.com>
To: Isaku Yamahata <isaku.yamahata@intel.com>
Cc: peter.maydell@linaro.org, Peter Maydell <Peter.maydel@linaro.org>,
f4bug@amsat.org, qemu-devel@nongnu.org, imammedo@redhat.com,
isaku.yamahata@gmail.com
Subject: Re: [PATCH v2 2/3] pci: sprinkle assert in PCI pin number
Date: Wed, 24 Mar 2021 12:37:22 -0400 [thread overview]
Message-ID: <20210324123128-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <dc9c8d2aa7bfcd82ba812f1ff5630a4cc0ffbbe7.1616519655.git.isaku.yamahata@intel.com>
On Tue, Mar 23, 2021 at 10:24:30AM -0700, Isaku Yamahata wrote:
> If a device model
> (a) doesn't set the value to a correct interrupt number and then
> (b) triggers an interrupt for itself,
> it's device model bug. Add assert on interrupt pin number to catch
> this kind of bug more obviously.
>
> Suggested-by: Peter Maydell <Peter.maydel@linaro.org>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> hw/pci/pci.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index ac9a24889c..cb6bab999b 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1450,6 +1450,8 @@ static void pci_irq_handler(void *opaque, int irq_num, int level)
> PCIDevice *pci_dev = opaque;
> int change;
>
> + assert(0 <= irq_num && irq_num < PCI_NUM_PINS);
> + assert(level == 0 || level == 1);
> change = level - pci_irq_state(pci_dev, irq_num);
> if (!change)
> return;
> @@ -1463,7 +1465,13 @@ static void pci_irq_handler(void *opaque, int irq_num, int level)
>
> static inline int pci_intx(PCIDevice *pci_dev)
> {
> - return pci_get_byte(pci_dev->config + PCI_INTERRUPT_PIN) - 1;
> + int intx = pci_get_byte(pci_dev->config + PCI_INTERRUPT_PIN) - 1;
> + /*
> + * This function is used to setup/trigger irq.
> + * So PIN = 0 (interrupt isn't used) doesn't make sense.
Well not really. It just returns it. But of course value -1 is not a
valid index. Better: callers must make sure the device actually has an
interrupt pin, otherwise PCI_INTERRUPT_PIN is 0 and intx is negative
here.
> + */
> + assert(0 <= intx && intx < PCI_NUM_PINS);
> + return intx;
> }
>
> qemu_irq pci_allocate_irq(PCIDevice *pci_dev)
> --
> 2.25.1
next prev parent reply other threads:[~2021-03-24 16:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 17:24 [PATCH v2 0/3] reinitialize ACPI PM device on reset Isaku Yamahata
2021-03-23 17:24 ` [PATCH v2 1/3] vt82c686.c: don't raise SCI when PCI_INTERRUPT_PIN isn't setup Isaku Yamahata
2021-03-23 18:43 ` Philippe Mathieu-Daudé
2021-03-23 22:33 ` BALATON Zoltan
2021-03-23 17:24 ` [PATCH v2 2/3] pci: sprinkle assert in PCI pin number Isaku Yamahata
2021-03-23 17:50 ` Peter Maydell
2021-03-24 16:37 ` Michael S. Tsirkin [this message]
2021-03-23 17:24 ` [PATCH v2 3/3] acpi:piix4, vt82c686: reinitialize acpi PM device on reset Isaku Yamahata
2021-03-23 19:36 ` Michael S. Tsirkin
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