KVM: selftests: Add option to rseq test to override /dev/cpu_dma_latency

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Add a "-l <latency>" param to the rseq test so that the user can override
/dev/cpu_dma_latency, as described by the test's suggested workaround for
not being able to complete enough migrations.

cpu_dma_latency is not a normal file, even as far as procfs files go.
Writes to cpu_dma_latency only persist so long as the file is open, e.g.
so that the kernel automatically reverts back to a power-optimized state
once the sensitive workload completes.  Provide the necessary functionality
instead of effectively forcing the user to write a non-obvious wrapper.

Cc: Dongsheng Zhang <dongsheng.x.zhang@intel.com>
Cc: Zide Chen <zide.chen@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20250401142238.819487-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Sean Christopherson 2025-04-01 07:22:38 -07:00 • committed by Paolo Bonzini

parent ef01cac401

commit 0297cdc12a

1 changed files with 25 additions and 6 deletions

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tools/testing/selftests/kvm/rseq_test.c

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