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[v9,0/7] QEMU CXL Provide mock CXL events and irq support

Message ID 20230530133603.16934-1-Jonathan.Cameron@huawei.com (mailing list archive)
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Series QEMU CXL Provide mock CXL events and irq support | expand

Message

Jonathan Cameron May 30, 2023, 1:35 p.m. UTC
v9: A few remaining QMP documentation formatting fixes from Markus.
Fingers crossed it's now clean!

Based on:
[PATCH v8 0/4] hw/cxl: Poison get, inject, clear

Based on: Message-ID: 20230526170010.574-1-Jonathan.Cameron@huawei.com

Updated cover letter from earlier versions:

One challenge here is striking the right balance between lots of constraints
in the injection code to enforce particular reserved bits etc by breaking
out all the flags as individual parameters vs having a reasonably concise
API.  I think this set strikes the right balance but others may well
disagree :)   Note that Ira raised the question of whether we should be
automatically establishing the volatile flag based on the Device Physical
Address of the injected error. My proposal is to not do so for now, but
to possibly revisit tightening the checking of injected errors in future.
Whilst the volatile flag is straight forwards, some of the other flags that
could be automatically set (or perhaps checked for validiaty) are much more
complex. Adding verification at this stage would greatly increase the
complexity of the patch + we are missing other elements that would interact
with this.  I'm not concerned about potential breaking of backwards compatibility
if it only related to the injection of errors that make no sense for a real
device.

CXL Event records inform the OS of various CXL device events.  Thus far CXL
memory devices are emulated and therefore don't naturally generate events.

Add an event infrastructure and mock event injection.  Previous versions
included a bulk insertion of lots of events.  However, this series focuses on
providing the ability to inject individual events through QMP.  Only the
General Media Event is included in this series as an example.  Other events can
be added pretty easily once the infrastructure is acceptable.

In addition, this version updates the code to be in line with the
specification based on discussions around the kernel patches.

Injection examples;

{ "execute": "cxl-inject-general-media-event",
    "arguments": {
        "path": "/machine/peripheral/cxl-mem0",
        "log": "informational",
        "flags": 1,
        "dpa": 1000,
        "descriptor": 3,
        "type": 3,
        "transaction-type": 192,
        "channel": 3,
        "device": 5,
        "component-id": "iras mem"
    }}


{ "execute": "cxl-inject-dram-event",
    "arguments": {
        "path": "/machine/peripheral/cxl-mem0",
        "log": "informational",
        "flags": 1,
        "dpa": 1000,
        "descriptor": 3,
        "type": 3,
        "transaction-type": 192,
        "channel": 3,
        "rank": 17,
        "nibble-mask": 37421234,
        "bank-group": 7,
        "bank": 11,
        "row": 2,
        "column": 77,
        "correction-mask": [33, 44, 55, 66]
    }}

{ "execute": "cxl-inject-memory-module-event",
  "arguments": {
    "path": "/machine/peripheral/cxl-mem0",
    "log": "informational",
    "flags": 1,
    "type": 3,
    "health-status": 3,
    "media-status": 7,
    "additional-status": 33,
    "life-used": 30,
    "temperature": -15,
    "dirty-shutdown-count": 4,
    "corrected-volatile-error-count": 3233,
    "corrected-persistent-error-count": 1300
  }}

Ira Weiny (4):
  hw/cxl/events: Add event status register
  hw/cxl/events: Wire up get/clear event mailbox commands
  hw/cxl/events: Add event interrupt support
  hw/cxl/events: Add injection of General Media Events

Jonathan Cameron (3):
  hw/cxl: Move CXLRetCode definition to cxl_device.h
  hw/cxl/events: Add injection of DRAM events
  hw/cxl/events: Add injection of Memory Module Events

 qapi/cxl.json               | 188 +++++++++++++++++++++++
 include/hw/cxl/cxl_device.h |  80 +++++++++-
 include/hw/cxl/cxl_events.h | 168 +++++++++++++++++++++
 hw/cxl/cxl-device-utils.c   |  43 +++++-
 hw/cxl/cxl-events.c         | 248 ++++++++++++++++++++++++++++++
 hw/cxl/cxl-mailbox-utils.c  | 166 ++++++++++++++------
 hw/mem/cxl_type3.c          | 292 +++++++++++++++++++++++++++++++++++-
 hw/mem/cxl_type3_stubs.c    |  35 +++++
 hw/cxl/meson.build          |   1 +
 9 files changed, 1165 insertions(+), 56 deletions(-)
 create mode 100644 include/hw/cxl/cxl_events.h
 create mode 100644 hw/cxl/cxl-events.c

Comments

Yuquan Wang March 15, 2024, 1:52 a.m. UTC | #1
Hello, Jonathan

When during the test of qmps of CXL events like "cxl-inject-general-media-event", 
I am confuesd about the argument "flags". According to "qapi/cxl.json" in qemu, 
this argument represents "Event Record Flags" in Common Event Record Format.
However, it seems like the specific 'Event Record Severity' in this field can be
different from the value of 'Event Status' in "Event Status Register". 

For instance (take an injection example in the coverlatter):

{ "execute": "cxl-inject-general-media-event",
    "arguments": {
        "path": "/machine/peripheral/cxl-mem0",
        "log": "informational",
        "flags": 1,
        "dpa": 1000,
        "descriptor": 3,
        "type": 3,
        "transaction-type": 192,
        "channel": 3,
        "device": 5,
        "component-id": "iras mem"
    }}

In my understanding, the 'Event Status' is informational and the 
'Event Record Severity' is Warning event, which means these two arguments are
independent of each other. Is my understanding correct?

Many thanks
Yuquan
Jonathan Cameron March 15, 2024, 10:24 a.m. UTC | #2
On Fri, 15 Mar 2024 09:52:28 +0800
Yuquan Wang <wangyuquan1236@phytium.com.cn> wrote:

> Hello, Jonathan
> 
> When during the test of qmps of CXL events like "cxl-inject-general-media-event", 
> I am confuesd about the argument "flags". According to "qapi/cxl.json" in qemu, 
> this argument represents "Event Record Flags" in Common Event Record Format.
> However, it seems like the specific 'Event Record Severity' in this field can be
> different from the value of 'Event Status' in "Event Status Register". 
> 
> For instance (take an injection example in the coverlatter):
> 
> { "execute": "cxl-inject-general-media-event",
>     "arguments": {
>         "path": "/machine/peripheral/cxl-mem0",
>         "log": "informational",
>         "flags": 1,
>         "dpa": 1000,
>         "descriptor": 3,
>         "type": 3,
>         "transaction-type": 192,
>         "channel": 3,
>         "device": 5,
>         "component-id": "iras mem"
>     }}
> 
> In my understanding, the 'Event Status' is informational and the 
> 'Event Record Severity' is Warning event, which means these two arguments are
> independent of each other. Is my understanding correct?

The event status registers dictates the notification path (which log).
So I think that's "informational" here.

Whereas flags is about the specific error. One case where they might be
different is where the Related Event Record Handle is set.
An error might be reported as
1) Several things that were non fatal (each with their own record)
2) In combination they result in a fatal situation (also has it's own record).

The QEMU injection shouldn't restrict these combinations more than the spec
does (which is not at all!).

This same disconnect in error severity is seen in UEFI CPER records for example
where there is a containing record with one severity field, but more specific
parts of record can have lower (or in theory higher) severity.

Jonathan


> 
> Many thanks
> Yuquan
>