Differential D20307

Add support for writing to guest memory in the debug server.
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Authored by jhb on May 18 2019, 6:27 PM.

Details

Reviewers

scottph
markj

Group Reviewers

bhyve

Commits

rS348212: Add support for writing to guest memory in the debug server.

Summary

Add a write_mem counterpart to read_mem to handle writes to MMIO.
Add support for the GDB 'M' packet to write bytes to the guest's memory. For MMIO writes, attempt to batch writes up into words. This is imprecise, but if you write a single 2 or 4-byte aligned word, it should be treated as a single MMIO write operation.
While here, tidy up the parsing of the 'm' command used for reading memory to match 'M'.

Test Plan

gdb tried to use this early on to set breakpoints

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

jhb created this revision.May 18 2019, 6:27 PM

Herald added subscribers: bcran, rgrimes, emaste. · View Herald TranscriptMay 18 2019, 6:27 PM

Harbormaster completed remote builds in B24304: Diff 57535.May 18 2019, 6:27 PM

jhb added a child revision: D20308: Add initial support for qSupported..May 18 2019, 6:35 PM

gdb_read_mem and gdb_write_mem could conceivably be factored together, though I'm not sure the complexity of that would be worth it. With or without that, this patch looks good to me.

This revision is now accepted and ready to land.May 21 2019, 9:03 PM

I did consider merging the read and write mem functions, but I was worried it might be a bit messy. I might still try it as a followup and see how it looks.

markj accepted this revision as: markj.May 22 2019, 7:57 PM

markj added a subscriber: markj.

markj added inline comments.