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2024-11-04KVM: selftests: memslot_perf_test: increase guest sync timeoutMaxim Levitsky
When memslot_perf_test is run nested, first iteration of test_memslot_rw_loop testcase, sometimes takes more than 2 seconds due to build of shadow page tables. Following iterations are fast. To be on the safe side, bump the timeout to 10 seconds. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Tested-by: Liam Merwick <liam.merwick@oracle.com> Reviewed-by: Liam Merwick <liam.merwick@oracle.com> Link: https://lore.kernel.org/r/20241004220153.287459-1-mlevitsk@redhat.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-10-01KVM: selftests: Fix build on architectures other than x86_64Mark Brown
The recent addition of support for testing with the x86 specific quirk KVM_X86_QUIRK_SLOT_ZAP_ALL disabled in the generic memslot tests broke the build of the KVM selftests for all other architectures: In file included from include/kvm_util.h:8, from include/memstress.h:13, from memslot_modification_stress_test.c:21: memslot_modification_stress_test.c: In function ‘main’: memslot_modification_stress_test.c:176:38: error: ‘KVM_X86_QUIRK_SLOT_ZAP_ALL’ undeclared (first use in this function) 176 | KVM_X86_QUIRK_SLOT_ZAP_ALL); | ^~~~~~~~~~~~~~~~~~~~~~~~~~ Add __x86_64__ guard defines to avoid building the relevant code on other architectures. Fixes: 61de4c34b51c ("KVM: selftests: Test memslot move in memslot_perf_test with quirk disabled") Fixes: 218f6415004a ("KVM: selftests: Allow slot modification stress test with quirk disabled") Reported-by: Aishwarya TCV <aishwarya.tcv@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> Message-ID: <20240930-kvm-build-breakage-v1-1-866fad3cc164@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-08-14KVM: selftests: Test memslot move in memslot_perf_test with quirk disabledYan Zhao
Add a new user option to memslot_perf_test to allow testing memslot move with quirk KVM_X86_QUIRK_SLOT_ZAP_ALL disabled. Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> Message-ID: <20240703021219.13939-1-yan.y.zhao@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-01-29KVM: selftests: Remove redundant newlinesAndrew Jones
TEST_* functions append their own newline. Remove newlines from TEST_* callsites to avoid extra newlines in output. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20231206170241.82801-8-ajones@ventanamicro.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-10-05KVM: selftests: Zero-initialize entire test_result in memslot perf testSean Christopherson
Zero-initialize the entire test_result structure used by memslot_perf_test instead of zeroing only the fields used to guard the pr_info() calls. gcc 13.2.0 is a bit overzealous and incorrectly thinks that rbestslottime's slot_runtime may be used uninitialized. In file included from memslot_perf_test.c:25: memslot_perf_test.c: In function ‘main’: include/test_util.h:31:22: error: ‘rbestslottime.slot_runtime.tv_nsec’ may be used uninitialized [-Werror=maybe-uninitialized] 31 | #define pr_info(...) printf(__VA_ARGS__) | ^~~~~~~~~~~~~~~~~~~ memslot_perf_test.c:1127:17: note: in expansion of macro ‘pr_info’ 1127 | pr_info("Best slot setup time for the whole test area was %ld.%.9lds\n", | ^~~~~~~ memslot_perf_test.c:1092:28: note: ‘rbestslottime.slot_runtime.tv_nsec’ was declared here 1092 | struct test_result rbestslottime; | ^~~~~~~~~~~~~ include/test_util.h:31:22: error: ‘rbestslottime.slot_runtime.tv_sec’ may be used uninitialized [-Werror=maybe-uninitialized] 31 | #define pr_info(...) printf(__VA_ARGS__) | ^~~~~~~~~~~~~~~~~~~ memslot_perf_test.c:1127:17: note: in expansion of macro ‘pr_info’ 1127 | pr_info("Best slot setup time for the whole test area was %ld.%.9lds\n", | ^~~~~~~ memslot_perf_test.c:1092:28: note: ‘rbestslottime.slot_runtime.tv_sec’ was declared here 1092 | struct test_result rbestslottime; | ^~~~~~~~~~~~~ That can't actually happen, at least not without the "result" structure in test_loop() also being used uninitialized, which gcc doesn't complain about, as writes to rbestslottime are all-or-nothing, i.e. slottimens can't be non-zero without slot_runtime being written. if (!data->mem_size && (!rbestslottime->slottimens || result.slottimens < rbestslottime->slottimens)) *rbestslottime = result; Zero-initialize the structures to make gcc happy even though this is likely a compiler bug. The cost to do so is negligible, both in terms of code and runtime overhead. The only downside is that the compiler won't warn about legitimate usage of "uninitialized" data, e.g. the test could end up consuming zeros instead of useful data. However, given that the test is quite mature and unlikely to see substantial changes, the odds of introducing such bugs are relatively low, whereas being able to compile KVM selftests with -Werror detects issues on a regular basis. Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Link: https://lore.kernel.org/r/20231005002954.2887098-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-08-02KVM: selftests: Rip out old, param-based guest assert macrosSean Christopherson
Drop the param-based guest assert macros and enable the printf versions for all selftests. Note! This change can affect tests even if they don't use directly use guest asserts! E.g. via library code, or due to the compiler making different optimization decisions. Link: https://lore.kernel.org/r/20230729003643.1053367-33-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-08-02KVM: selftests: Convert the memslot performance test to printf guest assertsSean Christopherson
Use the printf-based GUEST_ASSERT_EQ() in the memslot perf test instead of an half-baked open code version. Link: https://lore.kernel.org/r/20230729003643.1053367-16-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-02-07KVM: selftests: Assign guest page size in sync area early in memslot_perf_testGavin Shan
The guest page size in the synchronization area is needed by all test cases. So it's reasonable to set it in the unified preparation function (prepare_vm()). Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Link: https://lore.kernel.org/r/20230118092133.320003-3-gshan@redhat.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-02-07KVM: selftests: Remove duplicate VM creation in memslot_perf_testGavin Shan
Remove a spurious call to __vm_create_with_one_vcpu() that was introduced by a merge gone sideways. Fixes: eb5618911af0 ("Merge tag 'kvmarm-6.2' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD") Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Link: https://lore.kernel.org/r/20230118092133.320003-2-gshan@redhat.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-12-27KVM: selftests: Fix divide-by-zero bug in memslot_perf_testSean Christopherson
Check that the number of pages per slot is non-zero in get_max_slots() prior to computing the remaining number of pages. clang generates code that uses an actual DIV for calculating the remaining, which causes a #DE if the total number of pages is less than the number of slots. traps: memslot_perf_te[97611] trap divide error ip:4030c4 sp:7ffd18ae58f0 error:0 in memslot_perf_test[401000+cb000] Fixes: a69170c65acd ("KVM: selftests: memslot_perf_test: Report optimal memory slots") Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20221213001653.3852042-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-09Merge tag 'kvmarm-6.2' of ↵Paolo Bonzini
https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for 6.2 - Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. - Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on. - Merge the pKVM shadow vcpu state tracking that allows the hypervisor to have its own view of a vcpu, keeping that state private. - Add support for the PMUv3p5 architecture revision, bringing support for 64bit counters on systems that support it, and fix the no-quite-compliant CHAIN-ed counter support for the machines that actually exist out there. - Fix a handful of minor issues around 52bit VA/PA support (64kB pages only) as a prefix of the oncoming support for 4kB and 16kB pages. - Add/Enable/Fix a bunch of selftests covering memslots, breakpoints, stage-2 faults and access tracking. You name it, we got it, we probably broke it. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. As a side effect, this tag also drags: - The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring series - A shared branch with the arm64 tree that repaints all the system registers to match the ARM ARM's naming, and resulting in interesting conflicts
2022-11-16KVM: selftests: move common startup logic to kvm_util.cVishal Annapurve
Consolidate common startup logic in one place by implementing a single setup function with __attribute((constructor)) for all selftests within kvm_util.c. This allows moving logic like: /* Tell stdout not to buffer its content */ setbuf(stdout, NULL); to a single file for all selftests. This will also allow any required setup at entry in future to be done in common main function. Link: https://lore.kernel.org/lkml/Ywa9T+jKUpaHLu%2Fl@google.com Suggested-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Andrew Jones <andrew.jones@linux.dev> Reviewed-by: Peter Gonda <pgonda@google.com> Signed-off-by: Vishal Annapurve <vannapurve@google.com> Link: https://lore.kernel.org/r/20221115213845.3348210-2-vannapurve@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-11-16KVM: selftests: Automatically do init_ucall() for non-barebones VMsSean Christopherson
Do init_ucall() automatically during VM creation to kill two (three?) birds with one stone. First, initializing ucall immediately after VM creations allows forcing aarch64's MMIO ucall address to immediately follow memslot0. This is still somewhat fragile as tests could clobber the MMIO address with a new memslot, but it's safe-ish since tests have to be conversative when accounting for memslot0. And this can be hardened in the future by creating a read-only memslot for the MMIO page (KVM ARM exits with MMIO if the guest writes to a read-only memslot). Add a TODO to document that selftests can and should use a memslot for the ucall MMIO (doing so requires yet more rework because tests assumes thay can use all memslots except memslot0). Second, initializing ucall for all VMs prepares for making ucall initialization meaningful on all architectures. aarch64 is currently the only arch that needs to do any setup, but that will change in the future by switching to a pool-based implementation (instead of the current stack-based approach). Lastly, defining the ucall MMIO address from common code will simplify switching all architectures (except s390) to a common MMIO-based ucall implementation (if there's ever sufficient motivation to do so). Cc: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Andrew Jones <andrew.jones@linux.dev> Tested-by: Peter Gonda <pgonda@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20221006003409.649993-4-seanjc@google.com
2022-11-16KVM: selftests: Add atoi_positive() and atoi_non_negative() for input validationVipin Sharma
Many KVM selftests take command line arguments which are supposed to be positive (>0) or non-negative (>=0). Some tests do these validation and some missed adding the check. Add atoi_positive() and atoi_non_negative() to validate inputs in selftests before proceeding to use those values. Signed-off-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20221103191719.1559407-7-vipinsh@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-11-16KVM: selftests: Add atoi_paranoid() to catch errors missed by atoi()Vipin Sharma
atoi() doesn't detect errors. There is no way to know that a 0 return is correct conversion or due to an error. Introduce atoi_paranoid() to detect errors and provide correct conversion. Replace all atoi() calls with atoi_paranoid(). Signed-off-by: Vipin Sharma <vipinsh@google.com> Suggested-by: David Matlack <dmatlack@google.com> Suggested-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20221103191719.1559407-4-vipinsh@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-11-10KVM: selftests: memslot_perf_test: Report optimal memory slotsGavin Shan
The memory area in each slot should be aligned to host page size. Otherwise, the test will fail. For example, the following command fails with the following messages with 64KB-page-size-host and 4KB-pae-size-guest. It's not user friendly to abort the test. Lets do something to report the optimal memory slots, instead of failing the test. # ./memslot_perf_test -v -s 1000 Number of memory slots: 999 Testing map performance with 1 runs, 5 seconds each Adding slots 1..999, each slot with 8 pages + 216 extra pages last ==== Test Assertion Failure ==== lib/kvm_util.c:824: vm_adjust_num_guest_pages(vm->mode, npages) == npages pid=19872 tid=19872 errno=0 - Success 1 0x00000000004065b3: vm_userspace_mem_region_add at kvm_util.c:822 2 0x0000000000401d6b: prepare_vm at memslot_perf_test.c:273 3 (inlined by) test_execute at memslot_perf_test.c:756 4 (inlined by) test_loop at memslot_perf_test.c:994 5 (inlined by) main at memslot_perf_test.c:1073 6 0x0000ffff7ebb4383: ?? ??:0 7 0x00000000004021ff: _start at :? Number of guest pages is not compatible with the host. Try npages=16 Report the optimal memory slots instead of failing the test when the memory area in each slot isn't aligned to host page size. With this applied, the optimal memory slots is reported. # ./memslot_perf_test -v -s 1000 Number of memory slots: 999 Testing map performance with 1 runs, 5 seconds each Memslot count too high for this test, decrease the cap (max is 514) Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221020071209.559062-7-gshan@redhat.com
2022-11-10KVM: selftests: memslot_perf_test: Consolidate memoryGavin Shan
The addresses and sizes passed to vm_userspace_mem_region_add() and madvise() should be aligned to host page size, which can be 64KB on aarch64. So it's wrong by passing additional fixed 4KB memory area to various tests. Fix it by passing additional fixed 64KB memory area to various tests. We also add checks to ensure that none of host/guest page size exceeds 64KB. MEM_TEST_MOVE_SIZE is fixed up to 192KB either. With this, the following command works fine on 64KB-page-size-host and 4KB-page-size-guest. # ./memslot_perf_test -v -s 512 Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221020071209.559062-6-gshan@redhat.com
2022-11-10KVM: selftests: memslot_perf_test: Support variable guest page sizeGavin Shan
The test case is obviously broken on aarch64 because non-4KB guest page size is supported. The guest page size on aarch64 could be 4KB, 16KB or 64KB. This supports variable guest page size, mostly for aarch64. - The host determines the guest page size when virtual machine is created. The value is also passed to guest through the synchronization area. - The number of guest pages are unknown until the virtual machine is to be created. So all the related macros are dropped. Instead, their values are dynamically calculated based on the guest page size. - The static checks on memory sizes and pages becomes dependent on guest page size, which is unknown until the virtual machine is about to be created. So all the static checks are converted to dynamic checks, done in check_memory_sizes(). - As the address passed to madvise() should be aligned to host page, the size of page chunk is automatically selected, other than one page. - MEM_TEST_MOVE_SIZE has fixed and non-working 64KB. It will be consolidated in next patch. However, the comments about how it's calculated has been correct. - All other changes included in this patch are almost mechanical replacing '4096' with 'guest_page_size'. Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221020071209.559062-5-gshan@redhat.com
2022-11-10KVM: selftests: memslot_perf_test: Probe memory slots for onceGavin Shan
prepare_vm() is called in every iteration and run. The allowed memory slots (KVM_CAP_NR_MEMSLOTS) are probed for multiple times. It's not free and unnecessary. Move the probing logic for the allowed memory slots to parse_args() for once, which is upper layer of prepare_vm(). No functional change intended. Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221020071209.559062-4-gshan@redhat.com
2022-11-10KVM: selftests: memslot_perf_test: Consolidate loop conditions in prepare_vm()Gavin Shan
There are two loops in prepare_vm(), which have different conditions. 'slot' is treated as meory slot index in the first loop, but index of the host virtual address array in the second loop. It makes it a bit hard to understand the code. Change the usage of 'slot' in the second loop, to treat it as the memory slot index either. No functional change intended. Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221020071209.559062-3-gshan@redhat.com
2022-11-10KVM: selftests: memslot_perf_test: Use data->nslots in prepare_vm()Gavin Shan
In prepare_vm(), 'data->nslots' is assigned with 'max_mem_slots - 1' at the beginning, meaning they are interchangeable. Use 'data->nslots' isntead of 'max_mem_slots - 1'. With this, it becomes easier to move the logic of probing number of slots into upper layer in subsequent patches. No functional change intended. Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221020071209.559062-2-gshan@redhat.com
2022-07-13KVM: selftests: Fix filename reporting in guest assertsColton Lewis
Fix filename reporting in guest asserts by ensuring the GUEST_ASSERT macro records __FILE__ and substituting REPORT_GUEST_ASSERT for many repetitive calls to TEST_FAIL. Previously filename was reported by using __FILE__ directly in the selftest, wrongly assuming it would always be the same as where the assertion failed. Signed-off-by: Colton Lewis <coltonlewis@google.com> Reported-by: Ricardo Koller <ricarkol@google.com> Fixes: 4e18bccc2e5544f0be28fc1c4e6be47a469d6c60 Link: https://lore.kernel.org/r/20220615193116.806312-5-coltonlewis@google.com [sean: convert more TEST_FAIL => REPORT_GUEST_ASSERT instances] Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-06-11KVM: selftests: Purge vm+vcpu_id == vcpu sillinessSean Christopherson
Take a vCPU directly instead of a VM+vcpu pair in all vCPU-scoped helpers and ioctls. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-11KVM: selftests: Convert memslot_perf_test away from VCPU_IDSean Christopherson
Convert memslot_perf_test to use __vm_create_with_one_vcpu() and pass around a 'struct kvm_vcpu' object instead of using a global VCPU_ID. This is the first of many, many steps towards eliminating VCPU_ID from all KVM selftests, and towards eventually purging the VM+vcpu_id mess. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-21KVM: selftests: Make memslot_perf_test arch independentRicardo Koller
memslot_perf_test uses ucalls for synchronization between guest and host. Ucalls API is architecture independent: tests do not need to know details like what kind of exit they generate on a specific arch. More specifically, there is no need to check whether an exit is KVM_EXIT_IO in x86 for the host to know that the exit is ucall related, as get_ucall() already makes that check. Change memslot_perf_test to not require specifying what exit does a ucall generate. Also add a missing ucall_init. Signed-off-by: Ricardo Koller <ricarkol@google.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210907180957.609966-2-ricarkol@google.com
2021-06-24KVM: selftests: Unconditionally use memslot '0' for page table allocationsSean Christopherson
Drop the memslot param from virt_pg_map() and virt_map() and shove the hardcoded '0' down to the vm_phy_page_alloc() calls. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210622200529.3650424-13-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-08selftests: kvm: Add support for customized slot0 memory sizeZhenzhong Duan
Until commit 39fe2fc96694 ("selftests: kvm: make allocation of extra memory take effect", 2021-05-27), parameter extra_mem_pages was used only to calculate the page table size for all the memory chunks, because real memory allocation happened with calls of vm_userspace_mem_region_add() after vm_create_default(). Commit 39fe2fc96694 however changed the meaning of extra_mem_pages to the size of memory slot 0. This makes the memory allocation more flexible, but makes it harder to account for the number of pages needed for the page tables. For example, memslot_perf_test has a small amount of memory in slot 0 but a lot in other slots, and adding that memory twice (both in slot 0 and with later calls to vm_userspace_mem_region_add()) causes an error that was fixed in commit 000ac4295339 ("selftests: kvm: fix overlapping addresses in memslot_perf_test", 2021-05-29) Since both uses are sensible, add a new parameter slot0_mem_pages to vm_create_with_vcpus() and some comments to clarify the meaning of slot0_mem_pages and extra_mem_pages. With this change, memslot_perf_test can go back to passing the number of memory pages as extra_mem_pages. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Message-Id: <20210608233816.423958-4-zhenzhong.duan@intel.com> [Squashed in a single patch and rewrote the commit message. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-29selftests: kvm: fix overlapping addresses in memslot_perf_testPaolo Bonzini
vm_create allocates memory and maps it close to GPA. This memory is separate from what is allocated in subsequent calls to vm_userspace_mem_region_add, so it is incorrect to pass the test memory size to vm_create_default. Just pass a small fixed amount of memory which can be used later for page table, otherwise GPAs are already allocated at MEM_GPA and the test aborts. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-27selftests: kvm: do only 1 memslot_perf_test run by defaultPaolo Bonzini
The test takes a long time with the current implementation of memslots, so cut the run time a bit. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-27KVM: selftests: add a memslot-related performance benchmarkMaciej S. Szmigiero
This benchmark contains the following tests: * Map test, where the host unmaps guest memory while the guest writes to it (maps it). The test is designed in a way to make the unmap operation on the host take a negligible amount of time in comparison with the mapping operation in the guest. The test area is actually split in two: the first half is being mapped by the guest while the second half in being unmapped by the host. Then a guest <-> host sync happens and the areas are reversed. * Unmap test which is broadly similar to the above map test, but it is designed in an opposite way: to make the mapping operation in the guest take a negligible amount of time in comparison with the unmap operation on the host. This test is available in two variants: with per-page unmap operation or a chunked one (using 2 MiB chunk size). * Move active area test which involves moving the last (highest gfn) memslot a bit back and forth on the host while the guest is concurrently writing around the area being moved (including over the moved memslot). * Move inactive area test which is similar to the previous move active area test, but now guest writes all happen outside of the area being moved. * Read / write test in which the guest writes to the beginning of each page of the test area while the host writes to the middle of each such page. Then each side checks the values the other side has written. This particular test is not expected to give different results depending on particular memslots implementation, it is meant as a rough sanity check and to provide insight on the spread of test results expected. Each test performs its operation in a loop until a test period ends (this is 5 seconds by default, but it is configurable). Then the total count of loops done is divided by the actual elapsed time to give the test result. The tests have a configurable memslot cap with the "-s" test option, by default the system maximum is used. Each test is repeated a particular number of times (by default 20 times), the best result achieved is printed. The test memory area is divided equally between memslots, the reminder is added to the last memslot. The test area size does not depend on the number of memslots in use. The tests also measure the time that it took to add all these memslots. The best result from the tests that use the whole test area is printed after all the requested tests are done. In general, these tests are designed to use as much memory as possible (within reason) while still doing 100+ loops even on high memslot counts with the default test length. Increasing the test runtime makes it increasingly more likely that some event will happen on the system during the test run, which might lower the test result. Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Message-Id: <8d31bb3d92bc8fa33a9756fa802ee14266ab994e.1618253574.git.maciej.szmigiero@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>