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Ignore the write to AMD microcode update MSR by guest.
AbandonedPublic

Authored by anish on Apr 3 2016, 5:48 AM.

Details

Summary

If a guest try to update microcode register, don't fail it but silently drop the write.
Submitted by: Yamagi Burmeister

Test Plan

Tested on Ubuntu VM by writing to this MSR[0xc0010020].

Diff Detail

Repository
rS FreeBSD src repository - subversion
Lint
Lint OK
Unit
No Unit Test Coverage
Build Status
Buildable 3201
Build 3234: arc lint + arc unit

Event Timeline

anish retitled this revision from to Ignore the write to AMD microcode update MSR by guest..
anish updated this object.
anish edited the test plan for this revision. (Show Details)
anish added reviewers: grehan, neel.
grehan edited edge metadata.

Fix up the plurality a bit in the checkin comment e.g. "If a guest tries to update the microcode register" and it's good to go :)

This revision is now accepted and ready to land.Apr 5 2016, 6:48 PM
anish edited edge metadata.

Ignore the write to AMD microcode update MSR by guest.

Summary: Allow guest writes to AMD microcode update[0xc0010020] MSR without updating actul hardware MSR. This allows guest microcode update to go through which otherwise failing because wrmsr() was returning EINVAL.

Submitted by: Yamagi Burmeister

Test Plan: Tested on Ubuntu VM by writing to this MSR[0xc0010020].

Reviewers: neel, grehan

Subscribers:

This revision now requires review to proceed.Apr 10 2016, 4:57 PM

Was submitted by r297806