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perf intel-pt: Add guest_code support
A common case for KVM test programs is that the test program acts as the hypervisor, creating, running and destroying the virtual machine, and providing the guest object code from its own object code. In this case, the VM is not running an OS, but only the functions loaded into it by the hypervisor test program, and conveniently, loaded at the same virtual addresses. To support that, a new option "--guest-code" has been added in previous patches. In this patch, add support also to Intel PT. In particular, ensure guest_code thread is set up before attempting to walk object code or synthesize samples. Example: # perf record --kcore -e intel_pt/cyc/ -- tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.280 MB perf.data ] # perf script --guest-code --itrace=bep --ns -F-period,+addr,+flags [SNIP] tsc_msrs_test 18436 [007] 10897.962087733: branches: call ffffffffc13b2ff5 __vmx_vcpu_run+0x15 (vmlinux) => ffffffffc13b2f50 vmx_update_host_rsp+0x0 (vmlinux) tsc_msrs_test 18436 [007] 10897.962087733: branches: return ffffffffc13b2f5d vmx_update_host_rsp+0xd (vmlinux) => ffffffffc13b2ffa __vmx_vcpu_run+0x1a (vmlinux) tsc_msrs_test 18436 [007] 10897.962087733: branches: call ffffffffc13b303b __vmx_vcpu_run+0x5b (vmlinux) => ffffffffc13b2f80 vmx_vmenter+0x0 (vmlinux) tsc_msrs_test 18436 [007] 10897.962087836: branches: vmentry ffffffffc13b2f82 vmx_vmenter+0x2 (vmlinux) => 0 [unknown] ([unknown]) [guest/18436] 18436 [007] 10897.962087836: branches: vmentry 0 [unknown] ([unknown]) => 402c81 guest_code+0x131 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962087836: branches: call 402c81 guest_code+0x131 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dba0 ucall+0x0 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962088248: branches: vmexit 40dba0 ucall+0x0 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 0 [unknown] ([unknown]) tsc_msrs_test 18436 [007] 10897.962088248: branches: vmexit 0 [unknown] ([unknown]) => ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux) tsc_msrs_test 18436 [007] 10897.962088248: branches: jmp ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux) => ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux) tsc_msrs_test 18436 [007] 10897.962088256: branches: return ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux) => ffffffffc13b3040 __vmx_vcpu_run+0x60 (vmlinux) tsc_msrs_test 18436 [007] 10897.962088270: branches: return ffffffffc13b30b6 __vmx_vcpu_run+0xd6 (vmlinux) => ffffffffc13b2f2e vmx_vcpu_enter_exit+0x4e (vmlinux) [SNIP] tsc_msrs_test 18436 [007] 10897.962089321: branches: call ffffffffc13b2ff5 __vmx_vcpu_run+0x15 (vmlinux) => ffffffffc13b2f50 vmx_update_host_rsp+0x0 (vmlinux) tsc_msrs_test 18436 [007] 10897.962089321: branches: return ffffffffc13b2f5d vmx_update_host_rsp+0xd (vmlinux) => ffffffffc13b2ffa __vmx_vcpu_run+0x1a (vmlinux) tsc_msrs_test 18436 [007] 10897.962089321: branches: call ffffffffc13b303b __vmx_vcpu_run+0x5b (vmlinux) => ffffffffc13b2f80 vmx_vmenter+0x0 (vmlinux) tsc_msrs_test 18436 [007] 10897.962089424: branches: vmentry ffffffffc13b2f82 vmx_vmenter+0x2 (vmlinux) => 0 [unknown] ([unknown]) [guest/18436] 18436 [007] 10897.962089424: branches: vmentry 0 [unknown] ([unknown]) => 40dba0 ucall+0x0 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962089701: branches: jmp 40dc1b ucall+0x7b (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc39 ucall+0x99 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962089701: branches: jcc 40dc3c ucall+0x9c (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc20 ucall+0x80 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962089701: branches: jcc 40dc3c ucall+0x9c (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc20 ucall+0x80 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962089701: branches: jcc 40dc37 ucall+0x97 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc50 ucall+0xb0 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) [guest/18436] 18436 [007] 10897.962089878: branches: vmexit 40dc55 ucall+0xb5 (/home/ahunter/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 0 [unknown] ([unknown]) tsc_msrs_test 18436 [007] 10897.962089878: branches: vmexit 0 [unknown] ([unknown]) => ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux) tsc_msrs_test 18436 [007] 10897.962089878: branches: jmp ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux) => ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux) tsc_msrs_test 18436 [007] 10897.962089887: branches: return ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux) => ffffffffc13b3040 __vmx_vcpu_run+0x60 (vmlinux) tsc_msrs_test 18436 [007] 10897.962089901: branches: return ffffffffc13b30b6 __vmx_vcpu_run+0xd6 (vmlinux) => ffffffffc13b2f2e vmx_vcpu_enter_exit+0x4e (vmlinux) [SNIP] # perf kvm --guest-code --guest --host report -i perf.data --stdio | head -20 # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 12 of event 'instructions' # Event count (approx.): 2274583 # # Children Self Command Shared Object Symbol # ........ ........ ............. .................... ........................................... # 54.70% 0.00% tsc_msrs_test [kernel.vmlinux] [k] entry_SYSCALL_64_after_hwframe | ---entry_SYSCALL_64_after_hwframe do_syscall_64 | |--29.44%--syscall_exit_to_user_mode | exit_to_user_mode_prepare | task_work_run | __fput For more information about Perf tools support for Intel® Processor Trace refer: https://perf.wiki.kernel.org/index.php/Perf_tools_support_for_Intel%C2%AE_Processor_Trace Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: kvm@vger.kernel.org Link: https://lore.kernel.org/r/20220517131011.6117-7-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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‎tools/perf/Documentation/perf-intel-pt.txt‎

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Original file line numberDiff line numberDiff line change
@@ -1400,6 +1400,76 @@ There were none.
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:17006 17006 [001] 11500.262869216: ffffffff8220116e error_entry+0xe ([guest.kernel.kallsyms]) pushq %rax
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Tracing Virtual Machines - Guest Code
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-------------------------------------
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A common case for KVM test programs is that the test program acts as the
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hypervisor, creating, running and destroying the virtual machine, and
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providing the guest object code from its own object code. In this case,
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the VM is not running an OS, but only the functions loaded into it by the
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hypervisor test program, and conveniently, loaded at the same virtual
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addresses. To support that, option "--guest-code" has been added to perf script
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and perf kvm report.
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Here is an example tracing a test program from the kernel's KVM selftests:
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# perf record --kcore -e intel_pt/cyc/ -- tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test
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[ perf record: Woken up 1 times to write data ]
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[ perf record: Captured and wrote 0.280 MB perf.data ]
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# perf script --guest-code --itrace=bep --ns -F-period,+addr,+flags
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[SNIP]
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tsc_msrs_test 18436 [007] 10897.962087733: branches: call ffffffffc13b2ff5 __vmx_vcpu_run+0x15 (vmlinux) => ffffffffc13b2f50 vmx_update_host_rsp+0x0 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962087733: branches: return ffffffffc13b2f5d vmx_update_host_rsp+0xd (vmlinux) => ffffffffc13b2ffa __vmx_vcpu_run+0x1a (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962087733: branches: call ffffffffc13b303b __vmx_vcpu_run+0x5b (vmlinux) => ffffffffc13b2f80 vmx_vmenter+0x0 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962087836: branches: vmentry ffffffffc13b2f82 vmx_vmenter+0x2 (vmlinux) => 0 [unknown] ([unknown])
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[guest/18436] 18436 [007] 10897.962087836: branches: vmentry 0 [unknown] ([unknown]) => 402c81 guest_code+0x131 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962087836: branches: call 402c81 guest_code+0x131 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dba0 ucall+0x0 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962088248: branches: vmexit 40dba0 ucall+0x0 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 0 [unknown] ([unknown])
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tsc_msrs_test 18436 [007] 10897.962088248: branches: vmexit 0 [unknown] ([unknown]) => ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962088248: branches: jmp ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux) => ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962088256: branches: return ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux) => ffffffffc13b3040 __vmx_vcpu_run+0x60 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962088270: branches: return ffffffffc13b30b6 __vmx_vcpu_run+0xd6 (vmlinux) => ffffffffc13b2f2e vmx_vcpu_enter_exit+0x4e (vmlinux)
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[SNIP]
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tsc_msrs_test 18436 [007] 10897.962089321: branches: call ffffffffc13b2ff5 __vmx_vcpu_run+0x15 (vmlinux) => ffffffffc13b2f50 vmx_update_host_rsp+0x0 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962089321: branches: return ffffffffc13b2f5d vmx_update_host_rsp+0xd (vmlinux) => ffffffffc13b2ffa __vmx_vcpu_run+0x1a (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962089321: branches: call ffffffffc13b303b __vmx_vcpu_run+0x5b (vmlinux) => ffffffffc13b2f80 vmx_vmenter+0x0 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962089424: branches: vmentry ffffffffc13b2f82 vmx_vmenter+0x2 (vmlinux) => 0 [unknown] ([unknown])
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[guest/18436] 18436 [007] 10897.962089424: branches: vmentry 0 [unknown] ([unknown]) => 40dba0 ucall+0x0 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962089701: branches: jmp 40dc1b ucall+0x7b (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc39 ucall+0x99 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962089701: branches: jcc 40dc3c ucall+0x9c (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc20 ucall+0x80 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962089701: branches: jcc 40dc3c ucall+0x9c (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc20 ucall+0x80 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962089701: branches: jcc 40dc37 ucall+0x97 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 40dc50 ucall+0xb0 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test)
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[guest/18436] 18436 [007] 10897.962089878: branches: vmexit 40dc55 ucall+0xb5 (/home/user/git/work/tools/testing/selftests/kselftest_install/kvm/tsc_msrs_test) => 0 [unknown] ([unknown])
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tsc_msrs_test 18436 [007] 10897.962089878: branches: vmexit 0 [unknown] ([unknown]) => ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962089878: branches: jmp ffffffffc13b2fa0 vmx_vmexit+0x0 (vmlinux) => ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962089887: branches: return ffffffffc13b2fd2 vmx_vmexit+0x32 (vmlinux) => ffffffffc13b3040 __vmx_vcpu_run+0x60 (vmlinux)
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tsc_msrs_test 18436 [007] 10897.962089901: branches: return ffffffffc13b30b6 __vmx_vcpu_run+0xd6 (vmlinux) => ffffffffc13b2f2e vmx_vcpu_enter_exit+0x4e (vmlinux)
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[SNIP]
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# perf kvm --guest-code --guest --host report -i perf.data --stdio | head -20
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# To display the perf.data header info, please use --header/--header-only options.
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#
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#
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# Total Lost Samples: 0
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#
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# Samples: 12 of event 'instructions'
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# Event count (approx.): 2274583
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#
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# Children Self Command Shared Object Symbol
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# ........ ........ ............. .................... ...........................................
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#
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54.70% 0.00% tsc_msrs_test [kernel.vmlinux] [k] entry_SYSCALL_64_after_hwframe
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|
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---entry_SYSCALL_64_after_hwframe
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do_syscall_64
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|
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|--29.44%--syscall_exit_to_user_mode
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| exit_to_user_mode_prepare
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| task_work_run
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| __fput
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Event Trace
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-----------
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‎tools/perf/util/intel-pt.c‎

Lines changed: 18 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -192,6 +192,7 @@ struct intel_pt_queue {
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pid_t next_tid;
193193
struct thread *thread;
194194
struct machine *guest_machine;
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struct thread *guest_thread;
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struct thread *unknown_guest_thread;
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pid_t guest_machine_pid;
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bool exclude_kernel;
@@ -690,6 +691,11 @@ static int intel_pt_get_guest(struct intel_pt_queue *ptq)
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ptq->guest_machine = NULL;
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thread__zput(ptq->unknown_guest_thread);
692693

694+
if (symbol_conf.guest_code) {
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thread__zput(ptq->guest_thread);
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ptq->guest_thread = machines__findnew_guest_code(machines, pid);
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}
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machine = machines__find_guest(machines, pid);
694700
if (!machine)
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return -1;
@@ -753,11 +759,16 @@ static int intel_pt_walk_next_insn(struct intel_pt_insn *intel_pt_insn,
753759
cpumode = intel_pt_nr_cpumode(ptq, *ip, nr);
754760

755761
if (nr) {
756-
if (cpumode != PERF_RECORD_MISC_GUEST_KERNEL ||
762+
if ((!symbol_conf.guest_code && cpumode != PERF_RECORD_MISC_GUEST_KERNEL) ||
757763
intel_pt_get_guest(ptq))
758764
return -EINVAL;
759765
machine = ptq->guest_machine;
760-
thread = ptq->unknown_guest_thread;
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thread = ptq->guest_thread;
767+
if (!thread) {
768+
if (cpumode != PERF_RECORD_MISC_GUEST_KERNEL)
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return -EINVAL;
770+
thread = ptq->unknown_guest_thread;
771+
}
761772
} else {
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thread = ptq->thread;
763774
if (!thread) {
@@ -1335,6 +1346,7 @@ static void intel_pt_free_queue(void *priv)
13351346
if (!ptq)
13361347
return;
13371348
thread__zput(ptq->thread);
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thread__zput(ptq->guest_thread);
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thread__zput(ptq->unknown_guest_thread);
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intel_pt_decoder_free(ptq->decoder);
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zfree(&ptq->event_buf);
@@ -2407,6 +2419,10 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
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ptq->sample_ipc = ptq->state->flags & INTEL_PT_SAMPLE_IPC;
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}
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/* Ensure guest code maps are set up */
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if (symbol_conf.guest_code && (state->from_nr || state->to_nr))
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intel_pt_get_guest(ptq);
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/*
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* Do PEBS first to allow for the possibility that the PEBS timestamp
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* precedes the current timestamp.

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