Only clear io buffer after unsuccesfull guest call

[ludfjig]

We are currently zeroing out some buffers when we do not need to. By removing the extra clear, performance should increase:

Copy-pasted comment from code here

In the happy path we do not need to clear io-buffers from the host because:

• the serialized guest function call is be zeroed out by the guest during deserialization, see call to try_pop_shared_input_data_into::<FunctionCall>()
• the serialized guest function result is zeroed out by us (the host) during deserialization, see get_guest_function_call_result
• any serialized host function call are zeroed out by us (the host) during deserialization, see get_host_function_call
• any serialized host function result is zeroed out by the guest during deserialization, see get_host_return_value

In addition,this PR fixes an issue when host functions panicked, the associated mutexes were poisoned which prevented making further host calls to the same function. EDIT: this PR does not fix that

Closes #715

[Copilot]

Pull Request Overview

This PR optimizes performance by only clearing I/O buffers after unsuccessful guest calls, rather than clearing them after every call. Additionally, it fixes issues with poisoned mutexes when host functions panic and adds required system calls to the seccomp allowlist for the Rust panic handler.

Key changes:

• Conditional buffer clearing to improve performance in the happy path
• Enhanced panic handling for host functions with proper error propagation
• Addition of syscalls needed by Rust's panic handler to the seccomp allowlist

Reviewed Changes

Copilot reviewed 6 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/hyperlight_host/src/sandbox/initialized_multi_use.rs	Added conditional buffer clearing logic and comprehensive test for host function panic scenarios
src/hyperlight_host/src/sandbox/host_funcs.rs	Enhanced panic handling to extract and propagate panic messages as proper errors
src/hyperlight_host/src/func/host_functions.rs	Fixed poisoned mutex handling to allow recovery from panicked host function calls
src/hyperlight_host/src/error.rs	Added new HostFunctionPanic error variant for better error reporting
src/hyperlight_host/src/seccomp/guest.rs	Added syscalls required by Rust's panic handler to the allowlist
src/tests/rust_guests/simpleguest/src/main.rs	Added test guest function to trigger host function panics for testing

[danbugs]

LGTM