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Merged
merged 18 commits into from
Mar 27, 2025
Merged

Gdb support for mshv guests #327

merged 18 commits into from
Mar 27, 2025

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dblnz
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@dblnz dblnz commented Mar 5, 2025

This PR address the #220 issue.
Additionally, the first 7 commits refactor the existing guest debugging code and moves code from kvm.rs to a new file that is to contain the hypervisor specific debugging functionality.

@dblnz dblnz added the kind/enhancement For PRs adding features, improving functionality, docs, tests, etc. label Mar 5, 2025
@dblnz dblnz force-pushed the gdb-support-mshv branch from e82833e to 0119675 Compare March 5, 2025 16:49
@ludfjig
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ludfjig commented Mar 5, 2025

This looks great! I noticed the how-to-debug-a-hyperlgiht-guest.md only mentions KVM guests, so we might want to update that doc. Additionally we have a debugging-hyperlgiht.md doc that has no mention of gdb debugging at all. Perhaps we could add a link from that doc to how-to-debug-a-hyperlight-guest.md

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dblnz commented Mar 5, 2025

This looks great! I noticed the how-to-debug-a-hyperlgiht-guest.md only mentions KVM guests, so we might want to update that doc. Additionally we have a debugging-hyperlgiht.md doc that has no mention of gdb debugging at all. Perhaps we could add a link from that doc to how-to-debug-a-hyperlight-guest.md

Thanks, I forgot about the documentation.
I'll add another commit that addresses the documentation

ludfjig
ludfjig previously approved these changes Mar 7, 2025
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LGTM! It would be good if @syntactically could review as well

@dblnz dblnz force-pushed the gdb-support-mshv branch 2 times, most recently from 4df565e to ebdbe13 Compare March 12, 2025 14:00
@dblnz dblnz requested a review from syntactically March 13, 2025 10:08
ludfjig
ludfjig previously approved these changes Mar 14, 2025
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danbugs
danbugs reviewed Mar 17, 2025
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simongdavies
simongdavies previously approved these changes Mar 17, 2025
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Some minor questions/suggestions but otherwise this LGTM

dblnz added 17 commits March 19, 2025 23:50
@dblnz
dbg: change visibility of debugging related functions/structs
21be879 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: move kvm vcpu debug type to another file
77b69fc 
- this is done in preparation of accomodating support for other hypervisors
which means some of the functionality whould be common.
- moving the debug code to a separate file can enable us to
group common behavior in traits

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: move hardware breakpoints functionality to separate file
d60a5ca 
- also add a trait that contains all the needed methods for interacting
with a vCPU

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: move read/write registers and get_stop_reason to vCPU functional…
5f6357d 
…ity trait

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: modify hw breakpoints and move common functionality in trait
10d2c71 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: move read/write address and add/remove sw breakpoint to separate…
480a3d9 
… file

- add trait to define common behavior to be used by other hypervisors
  later

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: remove specific method that adds entry point breakpoint
338db62 
- it can be done using the generic way to add hw breakpoints
- also remove the entry point breakpoint after the vCPU stops to
avoid hanging there

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: improve vCPU exit reason checking
a5e88c4 
- verify the debug registers that report what kind of exception was triggered
- in case there is an unknown reason, report it as a SwBp so that the gdb
client can inspect what happened

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: prepare for mshv guest debugging implementation
06c9b94 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: add basic skeleton for mshv guest debug
b2dc614 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: add mshv intercepts for #DB and #BP exceptions
387333c 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: mshv guest debugging support for vCPU operations
7f542e1 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: mshv guest debugging support for memory inspection
f3701a7 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: read/write addresses check offset calculation
3c71783 
- use checked_sub to avoid issues from addresses that could cause
underflow

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: enable ci guest debugging tests on mshv
0b8ded6 
- change gdb commands in test to be usable with older gdb versions
- change Justfile to provide mshv3 feature
- change gdb test to invoke cargo test with correct features for mshv

Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: update documentation to specify the mshv debug support
f8aff0d 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz
dbg: add specific logging for each debug command error encountered
025a739 
Signed-off-by: Doru Blânzeanu <[email protected]>
@dblnz dblnz force-pushed the gdb-support-mshv branch from ebdbe13 to 025a739 Compare March 19, 2025 22:14
danbugs
danbugs approved these changes Mar 24, 2025
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LGTM–great work, Doru!

syntactically
syntactically approved these changes Mar 27, 2025
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Overall LGTM. Great work, especially given how little documentation there is for the HV interfaces, @dblnz !

@dblnz dblnz mentioned this pull request Mar 27, 2025
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@dblnz dblnz merged commit 54ffc0d into hyperlight-dev:main Mar 27, 2025
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@dblnz dblnz deleted the gdb-support-mshv branch March 27, 2025 15:19
@dblnz dblnz mentioned this pull request May 2, 2025
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@syntactically syntactically syntactically approved these changes

@danbugs danbugs danbugs approved these changes

@simongdavies simongdavies Awaiting requested review from simongdavies

@ludfjig ludfjig Awaiting requested review from ludfjig

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