[CI Check] Add Volatile Keyword to NvmExpress Passthru CQs #4320
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
added 2 commits
April 27, 2023 09:49
This updates the relevant functions that expect a non-volatile structure to be passed to them to take casts of the CQ now that it is volatile. Cc: Hao A Wu <hao.a.wu@intel.com> Cc: Ray Ni <ray.ni@intel.com> Cc: Jian J Wang <jian.j.wang@intel.com> Cc: Liming Gao <gaoliming@byosoft.com.cn> Cc: Michael Kubacki <mikuback@linux.microsoft.com> Cc: Sean Brogan <sean.brogan@microsoft.com> Signed-off-by: Oliver Smith-Denny <osde@linux.microsoft.com>
This applies the volatile keyword and appropriate casts to the NvmExpressPei's Passthru CQ. Cc: Hao A Wu <hao.a.wu@intel.com> Cc: Ray Ni <ray.ni@intel.com> Cc: Jian J Wang <jian.j.wang@intel.com> Cc: Liming Gao <gaoliming@byosoft.com.cn> Cc: Michael Kubacki <mikuback@linux.microsoft.com> Cc: Sean Brogan <sean.brogan@microsoft.com> Signed-off-by: Oliver Smith-Denny <osde@linux.microsoft.com>
|
Merged, as PR #4353 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
NVMe CQs are hardware queues mapped to EFI memory.
In the NVMExpress Passthru implementations in PEI and DXE,
it has been observed that NVMe CQs are not marked
volatile, meaning the compiler has significant leeway
to optimize accesses to these structures.
This led to an issue where the passthru driver waited
for a timeout period for an NVMe CQ to mark that it was
finished with a transaction, but the compiler had
optimized away the read to the actual HW mapped memory,
so the transaction had completed but the timeout continued.
Marking the CQs as volatile fixes this issue as the reads
happen to the actual HW.