Re: [Qemu-devel] [RFC PATCH 2/4] pcie-aer: Fix command pcie_aer_inject_error is invalid

[Marcel Apfelbaum <marcel.apfelbaum@gmail.com>]

On 01/12/2015 05:04 AM, Chen Fan wrote:
> in spec "PCI Express 3.0" section 6.2.6 Figure 6-3 virtual bridge part,
> the flowchart showing tell us SERR# enable at Bridge Control register
> associate with system error at Secondary Status register can send error
> message. but bridge_control from dev->config is NULL, and SERR# was set
> in dev->wmask in pcie_aer_init()
wmask denotes the register bits that can be written by the guest.

If you are referring to:
        pci_word_test_and_set_mask(dev->wmask + PCI_BRIDGE_CONTROL,
                                   PCI_BRIDGE_CTL_SERR);
that means that the OS *is able* to turn on/off SERR forwarding.


  which was implemented by root port and
> swith devices, so we should add wmask (for w/r) bit set for bridge control.
> we can user command like:
> qemu_system_x86_64:
> -device ioh3420,bus=pcie.0,addr=1c.0,multifunction=on,port=1,id=bridge1
> -device x3130-upstream,bus=bridge1,id=up.1,addr=00.0
> -device xio3130-downstream,bus=up.1,id=down.1,port=1,addr=00.0,chassis=5
>
> (qemu) pcie_aer_inject_error net0 POISON_TLP
>
> after that,
> guest can output the error message.
>
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>   hw/pci/pcie_aer.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/pci/pcie_aer.c b/hw/pci/pcie_aer.c
> index 7ca077a..571dc92 100644
> --- a/hw/pci/pcie_aer.c
> +++ b/hw/pci/pcie_aer.c
> @@ -231,7 +231,8 @@ pcie_aer_msg_alldev(PCIDevice *dev, const PCIEAERMsg *msg)
>    */
>   static bool pcie_aer_msg_vbridge(PCIDevice *dev, const PCIEAERMsg *msg)
>   {
> -    uint16_t bridge_control = pci_get_word(dev->config + PCI_BRIDGE_CONTROL);
Here we check if the Guest OS/firmware actually turned the #SERR forwarding on.

> +    uint16_t bridge_control = pci_get_word(dev->config + PCI_BRIDGE_CONTROL) |
> +                              pci_get_word(dev->wmask + PCI_BRIDGE_CONTROL);
I don't think that this check is correct given the above comments.
Please correct me if I mislead you,
Thanks,
Marcel


>
>       if (pcie_aer_msg_is_uncor(msg)) {
>           /* Received System Error */
>