RE: [RFC 10/10] tools: PCI: Add MSI-X support

From: Alan Douglas
Date: Tue Apr 24 2018 - 05:57:56 EST

Hi Gustavo,

On 10 April 2018 18:15, Gustavo Pimentel wrote:
> Adds MSI-X support to the pcitest tool and modified the script to
> accomodate this new type of interruption test.
> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
> ---
> include/uapi/linux/pcitest.h | 1 +
> tools/pci/pcitest.c | 18 +++++++++++++++++-
> tools/pci/ | 25 +++++++++++++++++++++++++
> 3 files changed, 43 insertions(+), 1 deletion(-)
I found some possible problems when testing with the Cadence EP driver. The problem
is that pcitest uses the BARs for tests, but we also use one for the MSI-X tables

In Cadence core the MSI-X table is in BAR0 by default, but this is configured to a size
of 0x80 in the test driver, since it is used as the test_reg_bar. So, I changed the
configuration to use BAR4 instead, which is configured to a size of 131072
in pci-efp-test.c, and this gives me enough space.

However, if I run the BAR tests in pcitest before running the MSI-X tests, the
MSI-X tests fail, since the BAR content is overwritten. It's not a problem with the
scenario in, but it would be if the module wasn't re-loaded.

So, wondering if we need to come up with some mechanism to specify that a specific
BAR will be used for MSI-X, and that its size and content shouldn't be modified by