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2022-02-10perf report: Output data file name in raw trace dumpAlexey Bayduraev9-37/+59
Print path and name of a data file into raw dump (-D) <file_offset>@<path/file>: 0x2226a@perf.data [0x30]: event: 9 or 0x15cc36@perf.data/data.7 [0x30]: event: 9 Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/e8378fd4910c10751b001be880705653989283c2.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf session: Load data directory files for analysisAlexey Bayduraev1-0/+133
Load data directory files and provide basic raw dump and aggregated analysis support of data directories in report mode, still with no memory consumption optimizations. READER_MAX_SIZE is chosen based on the results of measurements on different machines on perf.data directory sizes >1GB. On machines with big core count (192 cores) the difference between 1MB and 2MB is about 4%. Other sizes (>2MB) are quite equal to 2MB. On machines with small core count (4-24) there is no differences between 1-16 MB sizes. So this constant is 2MB. Suggested-by: Jiri Olsa <jolsa@kernel.org> Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/3f10c13a226c0ceb53e88a082f847b91c1ae2c25.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Implement compatibility checksAlexey Bayduraev1-3/+46
Implement compatibility checks for other modes and related command line options: asynchronous (--aio) trace streaming and affinity (--affinity) modes, pipe mode, AUX area tracing --snapshot and --aux-sample options, --switch-output, --switch-output-event, --switch-max-files and --timestamp-filename options. Parallel data streaming is compatible with Zstd compression (--compression-level) and external control commands (--control). CPU mask provided via -C option filters --threads specification masks. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/fadc1cf74057af4d5766248fcfe5cdde40732aa9.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Extend --threads command line optionAlexey Bayduraev3-4/+349
Extend --threads option in perf record command line interface. The option can have a value in the form of masks that specify CPUs to be monitored with data streaming threads and its layout in system topology. The masks can be filtered using CPU mask provided via -C option. The specification value can be user defined list of masks. Masks separated by colon define CPUs to be monitored by one thread and affinity mask of that thread is separated by slash. For example: <cpus mask 1>/<affinity mask 1>:<cpu mask 2>/<affinity mask 2> specifies parallel threads layout that consists of two threads with corresponding assigned CPUs to be monitored. The specification value can be a string e.g. "cpu", "core" or "package" meaning creation of data streaming thread for every CPU or core or package to monitor distinct CPUs or CPUs grouped by core or package. The option provided with no or empty value defaults to per-cpu parallel threads layout creating data streaming thread for every CPU being monitored. Document --threads option syntax and parallel data streaming modes in Documentation/perf-record.txt. Suggested-by: Jiri Olsa <jolsa@kernel.org> Suggested-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/079e2619be70c465317cf7c9fdaf5fa069728c32.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce --threads command line optionAlexey Bayduraev2-1/+51
Provide --threads option in perf record command line interface. The option creates a data streaming thread for each CPU in the system. Document --threads option in Documentation/perf-record.txt. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/01aeae43b047f428596c4ef9f9342ab94865cedd.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce data transferred and compressed statsAlexey Bayduraev1-3/+22
Introduce bytes_transferred and bytes_compressed stats so they would capture statistics for the related data buffer transfers. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/b5d598034c507dfb7544d2125500280b7d434764.1642440724.git.alexey.v.bayduraev@linux.intel.com [ Use PRiu64 to print u64 values, fixing the build on 32-bit architectures ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce compressor at mmap buffer objectAlexey Bayduraev3-7/+23
Introduce compressor object into mmap object so it could be used to pack the data stream from the corresponding kernel data buffer. Initialize and make use of the introduced per mmap compressor. Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Riccardo Mancini <rickyman7@gmail.com> Link: https://lore.kernel.org/r/80edc286cf6543139a7d5a91217605123aa0b50d.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce bytes written statsAlexey Bayduraev1-3/+18
Introduce a function to calculate the total amount of data written and use it to support the --max-size option. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/3e2c69186641446f8ab003ec209bccc762b3394d.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce data file at mmap buffer objectAlexey Bayduraev2-5/+33
Introduce data file objects into mmap object so it could be used to process and store data stream from the corresponding kernel data buffer. Initialize data files located at mmap buffer objects so trace data can be written into several data file located at data directory. Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Riccardo Mancini <rickyman7@gmail.com> Link: https://lore.kernel.org/r/177077f7734b63e5c999ccd75ac6dc3c694f0d0d.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Start threads in the beginning of trace streamingAlexey Bayduraev2-1/+121
Start thread in detached state because its management is implemented via messaging to avoid any scaling issues. Block signals prior thread start so only main tool thread would be notified on external async signals during data collection. Thread affinity mask is used to assign eligible CPUs for the thread to run. Wait and sync on thread start using thread ack pipe. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/95784dd9f7c81ee408eab27b50b4c09ad4cf7be6.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Stop threads in the end of trace streamingAlexey Bayduraev1-0/+31
Signal thread to terminate by closing write fd of msg pipe. Receive THREAD_MSG__READY message as the confirmation of the thread's termination. Stop threads created for parallel trace streaming prior their stats processing. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/55ef8cc5ec3a96360660d9dc1763573225325f8c.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce thread local variableAlexey Bayduraev1-46/+94
Introduce thread local variable and use it for threaded trace streaming. Use thread affinity mask instead of record affinity mask in affinity modes. Use evlist__ctlfd_update() to propagate control commands from thread object to global evlist object to enable evlist__ctlfd_* functionality. Move waking and sample statistic to struct record_thread and introduce record__waking function to calculate the total number of wakes. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/0d127555219991c1dcd6c6bb76b24fa6b78d2932.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce function to propagate control commandsAlexey Bayduraev2-0/+17
Introduce evlist__ctlfd_update() function to propagate external control commands to global evlist object. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/7df52c9816b13c74897b9e518128b29a391462fe.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce thread specific data arrayAlexey Bayduraev1-3/+244
Introduce thread specific data object and array of such objects to store and manage thread local data. Implement functions to allocate, initialize, finalize and release thread specific data. Thread local maps and overwrite_maps arrays keep pointers to mmap buffer objects to serve according to maps thread mask. Thread local pollfd array keeps event fds connected to mmaps buffers according to maps thread mask. Thread control commands are delivered via thread local comm pipes and ctlfd_pos fd. External control commands (--control option) are delivered via evlist ctlfd_pos fd and handled by the main tool thread. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/fc9f74af6f822d9c0fa0e145c3564a760dbe3d4b.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10tools lib: Introduce fdarray duplicate functionAlexey Bayduraev2-0/+18
Introduce a function to duplicate an existing file descriptor in the fdarray structure. The function returns the position of the duplicated file descriptor. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/2891f1def287d5863cc82683a4d5879195c8d90c.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10perf record: Introduce thread affinity and mmap masksAlexey Bayduraev1-0/+123
Introduce affinity and mmap thread masks. Thread affinity mask defines CPUs that a thread is allowed to run on. Thread maps mask defines mmap data buffers the thread serves to stream profiling data from. Reviewed-by: Riccardo Mancini <rickyman7@gmail.com> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Namhyung Kim <namhyung@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Antonov <alexander.antonov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Budankov <abudankov@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/9042bf7daf988e17e17e6acbf5d29590bde869cd.1642440724.git.alexey.v.bayduraev@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-10net: dsa: qca8k: fix noderef.cocci warningskernel test robot1-1/+1
drivers/net/dsa/qca8k.c:422:37-43: ERROR: application of sizeof to pointer sizeof when applied to a pointer typed expression gives the size of the pointer Generated by: scripts/coccinelle/misc/noderef.cocci Fixes: 90386223f44e ("net: dsa: qca8k: add support for larger read/write size with mgmt Ethernet") CC: Ansuel Smith <ansuelsmth@gmail.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: kernel test robot <lkp@intel.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20220209221304.GA17529@d2214a582157 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-10KVM: VMX: Use local pointer to vcpu_vmx in vmx_vcpu_after_set_cpuid()Oliver Upton1-2/+2
There is a local that contains a pointer to vcpu_vmx already. Just use that instead to get at the structure directly instead of doing pointer arithmetic. No functional change intended. Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220204204705.3538240-8-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: nSVM: Add enlightened MSR-Bitmap selftestVitaly Kuznetsov3-0/+177
Introduce a new test for Hyper-V nSVM extensions (Hyper-V on KVM) and add a test for enlightened MSR-Bitmap feature: - Intercept access to MSR_FS_BASE in L1 and check that this works with enlightened MSR-Bitmap disabled. - Enabled enlightened MSR-Bitmap and check that the intercept still works as expected. - Intercept access to MSR_GS_BASE but don't clear the corresponding bit from clean fields mask, KVM is supposed to skip updating MSR-Bitmap02 and thus the consequent access to the MSR from L2 will not get intercepted. - Finally, clear the corresponding bit from clean fields mask and check that access to MSR_GS_BASE is now intercepted. The test works with the assumption, that access to MSR_FS_BASE/MSR_GS_BASE is not intercepted for L1. If this ever becomes not true the test will fail as nested_svm_exit_handled_msr() always checks L1's MSR-Bitmap for L2 irrespective of clean fields. The behavior is correct as enlightened MSR-Bitmap feature is just an optimization, KVM is not obliged to ignore updates when the corresponding bit in clean fields stays clear. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220203104620.277031-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: nSVM: Update 'struct vmcb_control_area' definitionVitaly Kuznetsov1-1/+8
There's a copy of 'struct vmcb_control_area' definition in KVM selftests, update it to allow testing of the newly introduced features. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220203104620.277031-6-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: nSVM: Set up MSR-Bitmap for SVM guestsVitaly Kuznetsov2-0/+11
Similar to VMX, allocate memory for MSR-Bitmap and fill in 'msrpm_base_pa' in VMCB. To use it, tests will need to set INTERCEPT_MSR_PROT interception along with the required bits in the MSR-Bitmap. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220203104620.277031-5-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: nVMX: Add enlightened MSR-Bitmap selftestVitaly Kuznetsov1-0/+59
Introduce a test for enlightened MSR-Bitmap feature (Hyper-V on KVM): - Intercept access to MSR_FS_BASE in L1 and check that this works with enlightened MSR-Bitmap disabled. - Enabled enlightened MSR-Bitmap and check that the intercept still works as expected. - Intercept access to MSR_GS_BASE but don't clear the corresponding bit from 'hv_clean_fields', KVM is supposed to skip updating MSR-Bitmap02 and thus the consequent access to the MSR from L2 will not get intercepted. - Finally, clear the corresponding bit from 'hv_clean_fields' and check that access to MSR_GS_BASE is now intercepted. The test works with the assumption, that access to MSR_FS_BASE/MSR_GS_BASE is not intercepted for L1. If this ever becomes not true the test will fail as nested_vmx_exit_handled_msr() always checks L1's MSR-Bitmap for L2 irrespective of 'hv_clean_fields'. The behavior is correct as enlightened MSR-Bitmap feature is just an optimization, KVM is not obliged to ignore updates when the corresponding bit in 'hv_clean_fields' stays clear. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220203104620.277031-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: nVMX: Properly deal with 'hv_clean_fields'Vitaly Kuznetsov2-3/+152
Instead of just resetting 'hv_clean_fields' to 0 on every enlightened vmresume, do the expected cleaning of the corresponding bit on enlightened vmwrite. Avoid direct access to 'current_evmcs' from evmcs_test to support the change. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220203104620.277031-3-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: Adapt hyperv_cpuid test to the newly introduced Enlightened MSR-BitmapVitaly Kuznetsov1-12/+17
CPUID 0x40000000.EAX is now always present as it has Enlightened MSR-Bitmap feature bit set. Adapt the test accordingly. Opportunistically add a check for the supported eVMCS version range. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220203104620.277031-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: nSVM: Implement Enlightened MSR-Bitmap featureVitaly Kuznetsov3-13/+37
Similar to nVMX commit 502d2bf5f2fd ("KVM: nVMX: Implement Enlightened MSR Bitmap feature"), add support for the feature for nSVM (Hyper-V on KVM). Notable differences from nVMX implementation: - As the feature uses SW reserved fields in VMCB control, KVM needs to make sure it's dealing with a Hyper-V guest (kvm_hv_hypercall_enabled()). - 'msrpm_base_pa' needs to be always be overwritten in nested_svm_vmrun_msrpm(), even when the update is skipped. As an optimization, nested_vmcb02_prepare_control() copies it from VMCB01 so when MSR-Bitmap feature for L2 is disabled nothing needs to be done. - 'struct vmcb_ctrl_area_cached' needs to be extended with clean fields/sw reserved data and __nested_copy_vmcb_control_to_cache() needs to copy it so nested_svm_vmrun_msrpm() can use it later. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220202095100.129834-5-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: nSVM: Split off common definitions for Hyper-V on KVM and KVM on Hyper-VVitaly Kuznetsov2-24/+36
In preparation to implementing Enlightened MSR-Bitmap feature for Hyper-V on KVM, split off the required definitions into common 'svm/hyperv.h' header. No functional change intended. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220202095100.129834-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86: Make kvm_hv_hypercall_enabled() static inlineVitaly Kuznetsov2-6/+5
In preparation for using kvm_hv_hypercall_enabled() from SVM code, make it static inline to avoid the need to export it. The function is a simple check with only two call sites currently. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220202095100.129834-3-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be rebuiltVitaly Kuznetsov3-1/+15
Similar to nVMX commit ed2a4800ae9d ("KVM: nVMX: Track whether changes in L0 require MSR bitmap for L2 to be rebuilt"), introduce a flag to keep track of whether MSR bitmap for L2 needs to be rebuilt due to changes in MSR bitmap for L1 or switching to a different L2. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220202095100.129834-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: selftests: Add an option to disable MANUAL_PROTECT_ENABLE and INITIALLY_SETDavid Matlack1-2/+11
Add an option to dirty_log_perf_test.c to disable KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE and KVM_DIRTY_LOG_INITIALLY_SET so the legacy dirty logging code path can be tested. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-19-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Add tracepoint for splitting huge pagesDavid Matlack2-3/+30
Add a tracepoint that records whenever KVM eagerly splits a huge page and the error status of the split to indicate if it succeeded or failed and why. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-18-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Split huge pages mapped by the TDP MMU during KVM_CLEAR_DIRTY_LOGDavid Matlack7-33/+73
When using KVM_DIRTY_LOG_INITIALLY_SET, huge pages are not write-protected when dirty logging is enabled on the memslot. Instead they are write-protected once userspace invokes KVM_CLEAR_DIRTY_LOG for the first time and only for the specific sub-region being cleared. Enhance KVM_CLEAR_DIRTY_LOG to also try to split huge pages prior to write-protecting to avoid causing write-protection faults on vCPU threads. This also allows userspace to smear the cost of huge page splitting across multiple ioctls, rather than splitting the entire memslot as is the case when initially-all-set is not used. Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-17-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Split huge pages mapped by the TDP MMU when dirty logging is enabledDavid Matlack8-0/+295
When dirty logging is enabled without initially-all-set, try to split all huge pages in the memslot down to 4KB pages so that vCPUs do not have to take expensive write-protection faults to split huge pages. Eager page splitting is best-effort only. This commit only adds the support for the TDP MMU, and even there splitting may fail due to out of memory conditions. Failures to split a huge page is fine from a correctness standpoint because KVM will always follow up splitting by write-protecting any remaining huge pages. Eager page splitting moves the cost of splitting huge pages off of the vCPU threads and onto the thread enabling dirty logging on the memslot. This is useful because: 1. Splitting on the vCPU thread interrupts vCPUs execution and is disruptive to customers whereas splitting on VM ioctl threads can run in parallel with vCPU execution. 2. Splitting all huge pages at once is more efficient because it does not require performing VM-exit handling or walking the page table for every 4KiB page in the memslot, and greatly reduces the amount of contention on the mmu_lock. For example, when running dirty_log_perf_test with 96 virtual CPUs, 1GiB per vCPU, and 1GiB HugeTLB memory, the time it takes vCPUs to write to all of their memory after dirty logging is enabled decreased by 95% from 2.94s to 0.14s. Eager Page Splitting is over 100x more efficient than the current implementation of splitting on fault under the read lock. For example, taking the same workload as above, Eager Page Splitting reduced the CPU required to split all huge pages from ~270 CPU-seconds ((2.94s - 0.14s) * 96 vCPU threads) to only 1.55 CPU-seconds. Eager page splitting does increase the amount of time it takes to enable dirty logging since it has split all huge pages. For example, the time it took to enable dirty logging in the 96GiB region of the aforementioned test increased from 0.001s to 1.55s. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-16-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Separate TDP MMU shadow page allocation and initializationDavid Matlack1-9/+17
Separate the allocation of shadow pages from their initialization. This is in preparation for splitting huge pages outside of the vCPU fault context, which requires a different allocation mechanism. No functional changed intended. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-15-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Derive page role for TDP MMU shadow pages from parentDavid Matlack1-18/+19
Derive the page role from the parent shadow page, since the only thing that changes is the level. This is in preparation for splitting huge pages during VM-ioctls which do not have access to the vCPU MMU context. No functional change intended. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-14-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Remove redundant role overrides for TDP MMU shadow pagesDavid Matlack1-4/+0
The vCPU's mmu_role already has the correct values for direct, has_4_byte_gpte, access, and ad_disabled. Remove the code that was redundantly overwriting these fields with the same values. No functional change intended. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-13-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Refactor TDP MMU iterators to take kvm_mmu_page rootDavid Matlack3-17/+15
Instead of passing a pointer to the root page table and the root level separately, pass in a pointer to the root kvm_mmu_page struct. This reduces the number of arguments by 1, cutting down on line lengths. No functional change intended. Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-12-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Move restore_acc_track_spte() to spte.hDavid Matlack2-14/+15
restore_acc_track_spte() is pure SPTE bit manipulation, making it a good fit for spte.h. And now that the WARN_ON_ONCE() calls have been removed, there isn't any good reason to not inline it. This move also prepares for a follow-up commit that will need to call restore_acc_track_spte() from spte.c No functional change intended. Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-11-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Drop new_spte local variable from restore_acc_track_spte()David Matlack1-6/+5
The new_spte local variable is unnecessary. Deleting it can save a line of code and simplify the remaining lines a bit. No functional change intended. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-10-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Remove unnecessary warnings from restore_acc_track_spte()David Matlack1-3/+0
The warnings in restore_acc_track_spte() can be removed because the only caller checks is_access_track_spte(), and is_access_track_spte() checks !spte_ad_enabled(). In other words, the warning can never be triggered. No functional change intended. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-9-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Consolidate logic to atomically install a new TDP MMU page tableDavid Matlack1-32/+36
Consolidate the logic to atomically replace an SPTE with an SPTE that points to a new page table into a single helper function. This will be used in a follow-up commit to split huge pages, which involves replacing each huge page SPTE with an SPTE that points to a page table. Opportunistically drop the call to trace_kvm_mmu_get_page() in kvm_tdp_mmu_map() since it is redundant with the identical tracepoint in tdp_mmu_alloc_sp(). No functional change intended. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-8-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Rename handle_removed_tdp_mmu_page() to handle_removed_pt()David Matlack1-5/+3
First remove tdp_mmu_ from the name since it is redundant given that it is a static function in tdp_mmu.c. There is a pattern of using tdp_mmu_ as a prefix in the names of static TDP MMU functions, but all of the other handle_*() variants do not include such a prefix. So drop it entirely. Then change "page" to "pt" to convey that this is operating on a page table rather than an struct page. Purposely use "pt" instead of "sp" since this function takes the raw RCU-protected page table pointer as an argument rather than a pointer to the struct kvm_mmu_page. No functional change intended. Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-7-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Rename TDP MMU functions that handle shadow pagesDavid Matlack1-14/+14
Rename 3 functions in tdp_mmu.c that handle shadow pages: alloc_tdp_mmu_page() -> tdp_mmu_alloc_sp() tdp_mmu_link_page() -> tdp_mmu_link_sp() tdp_mmu_unlink_page() -> tdp_mmu_unlink_sp() These changed make tdp_mmu a consistent prefix before the verb in the function name, and make it more clear that these functions deal with kvm_mmu_page structs rather than struct pages. One could argue that "shadow page" is the wrong term for a page table in the TDP MMU since it never actually shadows a guest page table. However, "shadow page" (or "sp" for short) has evolved to become the standard term in KVM when referring to a kvm_mmu_page struct, and its associated page table and other metadata, regardless of whether the page table shadows a guest page table. So this commit just makes the TDP MMU more consistent with the rest of KVM. No functional change intended. Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-6-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Change tdp_mmu_{set,zap}_spte_atomic() to return 0/-EBUSYDavid Matlack1-21/+26
tdp_mmu_set_spte_atomic() and tdp_mmu_zap_spte_atomic() return a bool with true indicating the SPTE modification was successful and false indicating failure. Change these functions to return an int instead since that is the common practice. Opportunistically fix up the kernel-doc style for the Return section above tdp_mmu_set_spte_atomic(). No functional change intended. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-5-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Automatically update iter->old_spte if cmpxchg failsDavid Matlack1-29/+23
Consolidate a bunch of code that was manually re-reading the spte if the cmpxchg failed. There is no extra cost of doing this because we already have the spte value as a result of the cmpxchg (and in fact this eliminates re-reading the spte), and none of the call sites depend on iter->old_spte retaining the stale spte value. Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-4-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Rename __rmap_write_protect() to rmap_write_protect()David Matlack1-5/+5
The function formerly known as rmap_write_protect() has been renamed to kvm_vcpu_write_protect_gfn(), so we can get rid of the double underscores in front of __rmap_write_protect(). No functional change intended. Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-3-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86/mmu: Rename rmap_write_protect() to kvm_vcpu_write_protect_gfn()David Matlack1-3/+3
rmap_write_protect() is a poor name because it also write-protects SPTEs in the TDP MMU, not just SPTEs in the rmap. It is also confusing that rmap_write_protect() is not a simple wrapper around __rmap_write_protect(), since that is the common pattern for functions with double-underscore names. Rename rmap_write_protect() to kvm_vcpu_write_protect_gfn() to convey that KVM is write-protecting a specific gfn in the context of a vCPU. No functional change intended. Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220119230739.2234394-2-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86: Add checks for reserved-to-zero Hyper-V hypercall fieldsSean Christopherson2-0/+11
Add checks for the three fields in Hyper-V's hypercall params that must be zero. Per the TLFS, HV_STATUS_INVALID_HYPERCALL_INPUT is returned if "A reserved bit in the specified hypercall input value is non-zero." Note, some versions of the TLFS have an off-by-one bug for the last reserved field, and define it as being bits 64:60. See https://github.com/MicrosoftDocs/Virtualization-Documentation/pull/1682. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211207220926.718794-9-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86: Reject fixeds-size Hyper-V hypercalls with non-zero "var_cnt"Sean Christopherson1-6/+6
Reject Hyper-V hypercalls if the guest specifies a non-zero variable size header (var_cnt in KVM) for a hypercall that has a fixed header size. Per the TLFS: It is illegal to specify a non-zero variable header size for a hypercall that is not explicitly documented as accepting variable sized input headers. In such a case the hypercall will result in a return code of HV_STATUS_INVALID_HYPERCALL_INPUT. Note, at least some of the various DEBUG commands likely aren't allowed to use variable size headers, but the TLFS documentation doesn't clearly state what is/isn't allowed. Omit them for now to avoid unnecessary breakage. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211207220926.718794-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86: Shove vp_bitmap handling down into sparse_set_to_vcpu_mask()Sean Christopherson1-27/+38
Move the vp_bitmap "allocation" that's needed to handle mismatched vp_index values down into sparse_set_to_vcpu_mask() and drop __always_inline from said helper. The need for an intermediate vp_bitmap is a detail that's specific to the sparse translation with mismatched VP<=>vCPU indexes and does not need to be exposed to the caller. Regarding the __always_inline, prior to commit f21dd494506a ("KVM: x86: hyperv: optimize sparse VP set processing") the helper, then named hv_vcpu_in_sparse_set(), was a tiny bit of code that effectively boiled down to a handful of bit ops. The __always_inline was understandable, if not justifiable. Since the aforementioned change, sparse_set_to_vcpu_mask() is a chunky 350-450+ bytes of code without KASAN=y, and balloons to 1100+ with KASAN=y. In other words, it has no business being forcefully inlined. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211207220926.718794-7-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-02-10KVM: x86: Don't bother reading sparse banks that end up being ignoredSean Christopherson1-3/+16
When handling "sparse" VP_SET requests, don't read sparse banks that can't possibly contain a legal VP index instead of ignoring such banks later on in sparse_set_to_vcpu_mask(). This allows KVM to cap the size of its sparse_banks arrays for VP_SET at KVM_HV_MAX_SPARSE_VCPU_SET_BITS. Add a compile time assert that KVM_HV_MAX_SPARSE_VCPU_SET_BITS<=64, i.e. that KVM_MAX_VCPUS<=4096, as the TLFS allows for at most 64 sparse banks, and KVM will need to do _something_ to play nice with Hyper-V. Reducing the size of sparse_banks fudges around a compilation warning (that becomes error with KVM_WERROR=y) when CONFIG_KASAN_STACK=y, which is selected (and can't be unselected) by CONFIG_KASAN=y when using gcc (clang/LLVM is a stack hog in some cases so it's opt-in for clang). KASAN_STACK adds a redzone around every stack variable, which pushes the Hyper-V functions over the default limit of 1024. Ideally, KVM would flat out reject such impossibilities, but the TLFS explicitly allows providing empty banks, even if a bank can't possibly contain a valid VP index due to its position exceeding KVM's max. Furthermore, for a bit 1 in ValidBankMask, it is valid state for the corresponding element in BanksContents can be all 0s, meaning no processors are specified in this bank. Arguably KVM should reject and not ignore the "extra" banks, but that can be done independently and without bloating sparse_banks, e.g. by reading each "extra" 8-byte chunk individually. Reported-by: Ajay Garg <ajaygargnsit@gmail.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211207220926.718794-6-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>