Add preemption timer to bound TA execution - #907

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Add preemption timer to bound TA execution#907
Sangho Lee (sangho2) merged 8 commits into
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.
To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.

@sangho2Sangho Lee (sangho2) changed the title Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2) changed the title Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2) changed the title Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2) changed the title Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Sangho Lee (sangho2)force-pushed the sanghle/lvbs/timebomb branch 3 times, most recently from 7bea3f7 to e5adb24CompareJune 10, 2026 18:10
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@sangho2Sangho Lee (sangho2) added the must-not-merge:blocked-on-other-changes Other changes/PRs to be handled first. Label not needed for non-main changes. label Jun 15, 2026
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Potential conflict with PR #865. Merge it first and then this one.

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LGTM. Thanks!

Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs Outdated
Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
@sangho2Sangho Lee (sangho2) removed the must-not-merge:blocked-on-other-changes Other changes/PRs to be handled first. Label not needed for non-main changes. label Jun 26, 2026
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🤖 SemverChecks 🤖 No breaking API changes detected

Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.

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Sangho Lee (sangho2) added this pull request to the merge queueJun 26, 2026
Merged via the queue into main with commit 58c99c7Jun 27, 2026
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Add preemption timer to bound TA execution - #907
Merged
Sangho Lee (sangho2) merged 8 commits into
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sanghle/lvbs/timebomb
Jun 27, 2026
Merged
Add preemption timer to bound TA execution#907
Sangho Lee (sangho2) merged 8 commits into
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
changed the title
Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
Outdated

Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
@sangho2
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added this pull request to the merge queueJun 26, 2026

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Add preemption timer to bound TA execution - #907
Merged
Sangho Lee (sangho2) merged 8 commits into
mainfrom 
sanghle/lvbs/timebomb
Jun 27, 2026
Merged
Add preemption timer to bound TA execution#907
Sangho Lee (sangho2) merged 8 commits into
mainfrom 
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
changed the title
Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
Outdated

Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
@sangho2Sangho Lee (sangho2)
removed
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must-not-merge:blocked-on-other-changes
Other changes/PRs to be handled first. Label not needed for non-main changes.
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
@sangho2
Sangho Lee (sangho2)
added this pull request to the merge queueJun 26, 2026

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Add preemption timer to bound TA execution - #907
Merged
Sangho Lee (sangho2) merged 8 commits into
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sanghle/lvbs/timebomb
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Merged
Add preemption timer to bound TA execution#907
Sangho Lee (sangho2) merged 8 commits into
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
changed the title
Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
Outdated

Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
@sangho2Sangho Lee (sangho2)
removed
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
@sangho2
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added this pull request to the merge queueJun 26, 2026

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Add preemption timer to bound TA execution - #907
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Add preemption timer to bound TA execution#907
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
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Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
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Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
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Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
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Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
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Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
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Add preemption timer to bound TA execution - #907
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Add preemption timer to bound TA execution#907
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
changed the title
Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2)
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Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
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Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
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Skip to content
Add preemption timer to bound TA execution - #907
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Merged
Add preemption timer to bound TA execution#907
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
changed the title
Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
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Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
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Add preemption timer to bound TA execution - #907
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Add preemption timer to bound TA execution#907
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This PR adds a timer-based mechanism for preempting TAs on the LVBS platform. In OP-TEE, TA execution is unbounded because there is no secure-world scheduler: if a TA spins in an infinite loop, it can hold the (V)CPU indefinitely. On Arm TrustZone, the normal world can eventually regain control by interrupting the secure world. However, in Hyper-V, VTL0 is not allowed to interrupt VTL1.

To overcome this problem, this PR implements a VTL1-local one-shot preemption timer based on the Hyper-V synthetic timer to limit the execution time of each TA command invocation (which could span multiple syscalls). If it fires, the VTL1 kernel kills the TA and returns back to VTL0.
@sangho2Sangho Lee (sangho2)
changed the title
Add local APIC timebomb for TA preemptionAdd timebomb for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add timebomb for TA preemptionAdd LVBS timer for TA preemptionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Add LVBS timer for TA preemptionPreemption timer to bound TA executionJun 10, 2026
@sangho2Sangho Lee (sangho2)
changed the title
Preemption timer to bound TA executionAdd preemption timer to bound TA executionJun 10, 2026
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Potential conflict with PR #865. Merge it first and then this one.
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LGTM. Thanks!
Comment threadlitebox_platform_lvbs/Cargo.toml
Comment threadlitebox_platform_lvbs/src/lib.rs
Outdated

Comment threadlitebox_platform_lvbs/src/arch/x86/timer.rs
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🤖 SemverChecks 🤖 No breaking API changes detected
Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.
@sangho2
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