Re: [PATCH 3/4] cxl/events: Add extra validity checks for CVME count in DRAM Event Record

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Wed, 16 Jul 2025 11:49:44 +0100
<shiju.jose@huawei.com> wrote:

> From: Shiju Jose <shiju.jose@huawei.com>
> 
> According to the CXL Specification Revision 3.2, Section 8.2.10.2.1.2,
> Table 8-58 (DRAM Event Record), the CVME (Corrected Volatile Memory Error)
> Count field is valid under the following conditions:
> 1. The Threshold Event bit is set in the Memory Event Descriptor field,
> and
> 2. The CVME Count must be greater than 0 for events where the Advanced
> Programmable Threshold Counter has expired.
> 
> Additionally, if the Advanced Programmable Corrected Memory Error Counter
> Expire bit in the Memory Event Type field is set, then the Threshold Event
> bit in the Memory Event Descriptor field shall also be set.
> 
> Add validity checks for the above conditions while reporting the event to
> the userspace.
> 
> Note: CXL spec rev3.2 Table 8-58. DRAM Event Record, (Field: CVME Count
> at Event), "For events in which the advanced programmable threshold
> counter has expired, this field value shall be a value greater than 0.
> Counter expiration events in which the corrected memory error count
> is 0 shall not generate a media event record".
> Q: Should kernel drop the event record in this case or user space
> to handle?
> 
Would be reasonable to combine this with previous patch but I don't mind
that much.

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>