Re: [PATCH] hw/cxl/device: Add Flex Bus Port DVSEC

[Jonathan Cameron]

On Tue, 13 Dec 2022 16:34:52 -0800
Ira Weiny <ira.weiny@intel.com> wrote:

> The Flex Bus Port DVSEC was missing on type 3 devices which was blocking
> RAS checks.[1]
> 
> Add the Flex Bus Port DVSEC to type 3 devices as per CXL 3.0 8.2.1.3.
> 
> [1] 
> https://lore.kernel.org/linux-cxl/167096738875.2861540.11815053323626849940.stgit@djiang5-desk3.ch.intel.com/
> 
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Ben Widawsky <bwidawsk@kernel.org>
> Cc: qemu-devel@nongnu.org
> Cc: linux-cxl@vger.kernel.org
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Not sure how we missed this one given the whole fun a while back with Mem 
Enable not
being set by the kernel code.  Ah well - I'm not going to go digging in the 
history
for that.

Minor thing inline - unlike root ports, switches etc, type 3 device should not
report CXL.cache support.

Jonathan


> ---
>  hw/mem/cxl_type3.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
> index 0317bd96a6fb..27f6ac0cb3c1 100644
> --- a/hw/mem/cxl_type3.c
> +++ b/hw/mem/cxl_type3.c
> @@ -416,6 +416,17 @@ static void build_dvsecs(CXLType3Dev *ct3d)
>      cxl_component_create_dvsec(cxl_cstate, CXL2_TYPE3_DEVICE,
>                                 GPF_DEVICE_DVSEC_LENGTH, GPF_DEVICE_DVSEC,
>                                 GPF_DEVICE_DVSEC_REVID, dvsec);
> +
> +    dvsec = (uint8_t *)&(CXLDVSECPortFlexBus){
> +        .cap                     = 0x27, /* Cache, IO, Mem, non-MLD */

Type 3 typically wouldn't support cache.  Probably want the comment to include
bit 5 (68B Flit and VH capable) That should probably true in the other instances
of this as well.


> +        .ctrl                    = 0x02, /* IO always enabled */
> +        .status                  = 0x27, /* same as capabilities */
Again, not cache.

> +        .rcvd_mod_ts_data_phase1 = 0xef, /* WTF? */
> +    };
> +    cxl_component_create_dvsec(cxl_cstate, CXL2_TYPE3_DEVICE,
> +                               PCIE_FLEXBUS_PORT_DVSEC_LENGTH_2_0,
> +                               PCIE_FLEXBUS_PORT_DVSEC,
> +                               PCIE_FLEXBUS_PORT_DVSEC_REVID_2_0, dvsec);
>  }
>  
>  static void hdm_decoder_commit(CXLType3Dev *ct3d, int which)
> 
> ---
> base-commit: e11b57108b0cb746bb9f3887054f34a2f818ed79
> change-id: 20221213-ira-flexbus-port-ce526de8111d
> 
> Best regards,