History log of /linux-master/tools/testing/selftests/kvm/memslot_perf_test.c
Revision Date Author Comments
# 250e138d 06-Dec-2023 Andrew Jones <ajones@ventanamicro.com>

KVM: selftests: Remove redundant newlines

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>


# 6313e096 04-Oct-2023 Sean Christopherson <seanjc@google.com>

KVM: selftests: Zero-initialize entire test_result in memslot perf test

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>


# 7ce7f8e7 28-Jul-2023 Sean Christopherson <seanjc@google.com>

KVM: selftests: Rip out old, param-based guest assert macros

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>


# c55a475d 28-Jul-2023 Sean Christopherson <seanjc@google.com>

KVM: selftests: Convert the memslot performance test to printf guest asserts

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>


# 45f67955 18-Jan-2023 Gavin Shan <gshan@redhat.com>

KVM: selftests: Assign guest page size in sync area early in memslot_perf_test

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>


# e5b42687 18-Jan-2023 Gavin Shan <gshan@redhat.com>

KVM: selftests: Remove duplicate VM creation in memslot_perf_test

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>


# d61a12cb 12-Dec-2022 Sean Christopherson <seanjc@google.com>

KVM: selftests: Fix divide-by-zero bug in memslot_perf_test

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>


# 197ebb71 15-Nov-2022 Vishal Annapurve <vannapurve@google.com>

KVM: selftests: move common startup logic to kvm_util.c

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>


# dc88244b 05-Oct-2022 Sean Christopherson <seanjc@google.com>

KVM: selftests: Automatically do init_ucall() for non-barebones VMs

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


# 0001725d 03-Nov-2022 Vipin Sharma <vipinsh@google.com>

KVM: selftests: Add atoi_positive() and atoi_non_negative() for input validation

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>


# 018ea2d7 03-Nov-2022 Vipin Sharma <vipinsh@google.com>

KVM: selftests: Add atoi_paranoid() to catch errors missed by atoi()

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>


# a69170c6 20-Oct-2022 Gavin Shan <gshan@redhat.com>

KVM: selftests: memslot_perf_test: Report optimal memory slots

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


# 88a64e65 20-Oct-2022 Gavin Shan <gshan@redhat.com>

KVM: selftests: memslot_perf_test: Consolidate memory

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


# 8675c6f2 20-Oct-2022 Gavin Shan <gshan@redhat.com>

KVM: selftests: memslot_perf_test: Support variable guest page size

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


# 34396437 20-Oct-2022 Gavin Shan <gshan@redhat.com>

KVM: selftests: memslot_perf_test: Probe memory slots for once

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


# 2aae5e67 20-Oct-2022 Gavin Shan <gshan@redhat.com>

KVM: selftests: memslot_perf_test: Consolidate loop conditions in prepare_vm()

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


# 3bfadb23 20-Oct-2022 Gavin Shan <gshan@redhat.com>

KVM: selftests: memslot_perf_test: Use data->nslots in prepare_vm()

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


# 594a1c27 15-Jun-2022 Colton Lewis <coltonlewis@google.com>

KVM: selftests: Fix filename reporting in guest asserts

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>


# 768e9a61 02-Jun-2022 Sean Christopherson <seanjc@google.com>

KVM: selftests: Purge vm+vcpu_id == vcpu silliness

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>


# e82e630b 15-Feb-2022 Sean Christopherson <seanjc@google.com>

KVM: selftests: Convert memslot_perf_test away from VCPU_ID

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>


# ffb4ce3c 07-Sep-2021 Ricardo Koller <ricarkol@google.com>

KVM: selftests: Make memslot_perf_test arch independent

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


# 4307af73 22-Jun-2021 Sean Christopherson <seanjc@google.com>

KVM: selftests: Unconditionally use memslot '0' for page table allocations

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>


# f53b16ad 08-Jun-2021 Zhenzhong Duan <zhenzhong.duan@intel.com>

selftests: kvm: Add support for customized slot0 memory size

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>


# 000ac429 28-May-2021 Paolo Bonzini <pbonzini@redhat.com>

selftests: kvm: fix overlapping addresses in memslot_perf_test

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>


# fb0f9479 26-May-2021 Paolo Bonzini <pbonzini@redhat.com>

selftests: kvm: do only 1 memslot_perf_test run by default

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>


# cad347fa 13-Apr-2021 Maciej S. Szmigiero <maciej.szmigiero@oracle.com>

KVM: selftests: add a memslot-related performance benchmark

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>