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Message-ID: <7273e4d4-49d0-829b-630a-273bda29ef7e@oracle.com>
Date: Thu, 9 Apr 2020 11:02:22 -0700
From: Krish Sadhukhan <krish.sadhukhan@...cle.com>
To: Wainer dos Santos Moschetta <wainersm@...hat.com>,
pbonzini@...hat.com, kvm@...r.kernel.org
Cc: drjones@...hat.com, david@...hat.com, linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v4 2/2] selftests: kvm: Add mem_slot_test test
On 4/8/20 8:01 PM, Wainer dos Santos Moschetta wrote:
>
> On 4/8/20 10:31 PM, Krish Sadhukhan wrote:
>>
>> On 4/8/20 3:08 PM, Wainer dos Santos Moschetta wrote:
>>> This patch introduces the mem_slot_test test which checks
>>> an VM can have added memory slots up to the limit defined in
>>> KVM_CAP_NR_MEMSLOTS. Then attempt to add one more slot to
>>> verify it fails as expected.
>>>
>>> Signed-off-by: Wainer dos Santos Moschetta <wainersm@...hat.com>
>>> ---
>>> tools/testing/selftests/kvm/.gitignore | 1 +
>>> tools/testing/selftests/kvm/Makefile | 3 +
>>> tools/testing/selftests/kvm/mem_slot_test.c | 76
>>> +++++++++++++++++++++
>>> 3 files changed, 80 insertions(+)
>>> create mode 100644 tools/testing/selftests/kvm/mem_slot_test.c
>>>
>>> diff --git a/tools/testing/selftests/kvm/.gitignore
>>> b/tools/testing/selftests/kvm/.gitignore
>>> index 16877c3daabf..127d27188427 100644
>>> --- a/tools/testing/selftests/kvm/.gitignore
>>> +++ b/tools/testing/selftests/kvm/.gitignore
>>> @@ -21,4 +21,5 @@
>>> /demand_paging_test
>>> /dirty_log_test
>>> /kvm_create_max_vcpus
>>> +/mem_slot_test
>>> /steal_time
>>> diff --git a/tools/testing/selftests/kvm/Makefile
>>> b/tools/testing/selftests/kvm/Makefile
>>> index 712a2ddd2a27..338b6cdce1a0 100644
>>> --- a/tools/testing/selftests/kvm/Makefile
>>> +++ b/tools/testing/selftests/kvm/Makefile
>>> @@ -32,12 +32,14 @@ TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
>>> TEST_GEN_PROGS_x86_64 += demand_paging_test
>>> TEST_GEN_PROGS_x86_64 += dirty_log_test
>>> TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus
>>> +TEST_GEN_PROGS_x86_64 += mem_slot_test
>>> TEST_GEN_PROGS_x86_64 += steal_time
>>> TEST_GEN_PROGS_aarch64 += clear_dirty_log_test
>>> TEST_GEN_PROGS_aarch64 += demand_paging_test
>>> TEST_GEN_PROGS_aarch64 += dirty_log_test
>>> TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus
>>> +TEST_GEN_PROGS_aarch64 += mem_slot_test
>>> TEST_GEN_PROGS_aarch64 += steal_time
>>> TEST_GEN_PROGS_s390x = s390x/memop
>>> @@ -46,6 +48,7 @@ TEST_GEN_PROGS_s390x += s390x/sync_regs_test
>>> TEST_GEN_PROGS_s390x += demand_paging_test
>>> TEST_GEN_PROGS_s390x += dirty_log_test
>>> TEST_GEN_PROGS_s390x += kvm_create_max_vcpus
>>> +TEST_GEN_PROGS_s390x += mem_slot_test
>>> TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M))
>>> LIBKVM += $(LIBKVM_$(UNAME_M))
>>> diff --git a/tools/testing/selftests/kvm/mem_slot_test.c
>>> b/tools/testing/selftests/kvm/mem_slot_test.c
>>> new file mode 100644
>>> index 000000000000..7c1009f0bc07
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/kvm/mem_slot_test.c
>>> @@ -0,0 +1,76 @@
>>> +// SPDX-License-Identifier: GPL-2.0-only
>>> +/*
>>> + * mem_slot_test
>>> + *
>>> + * Copyright (C) 2020, Red Hat, Inc.
>>> + *
>>> + * Test suite for memory region operations.
>>> + */
>>> +#define _GNU_SOURCE /* for program_invocation_short_name */
>>> +#include <linux/kvm.h>
>>> +#include <sys/mman.h>
>>> +
>>> +#include "test_util.h"
>>> +#include "kvm_util.h"
>>> +
>>> +/*
>>> + * Test it can be added memory slots up to KVM_CAP_NR_MEMSLOTS,
>>> then any
>>> + * tentative to add further slots should fail.
>>> + */
>>> +static void test_add_max_slots(void)
>>> +{
>>> + int ret;
>>> + struct kvm_vm *vm;
>>> + uint32_t max_mem_slots;
>>> + uint32_t slot;
>>> + uint64_t guest_addr;
>>> + uint64_t mem_reg_npages;
>>> + uint64_t mem_reg_size;
>>> + void *mem;
>>> +
>>> + max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
>>> + TEST_ASSERT(max_mem_slots > 0,
>>> + "KVM_CAP_NR_MEMSLOTS should be greater than 0");
>>> + pr_info("Allowed number of memory slots: %i\n", max_mem_slots);
>>> +
>>> + vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
>>> +
>>> + /*
>>> + * Uses 1MB sized/aligned memory region since this is the minimal
>>> + * required on s390x.
>>> + */
>>> + mem_reg_size = 0x100000;
>>> + mem_reg_npages = vm_calc_num_guest_pages(VM_MODE_DEFAULT,
>>> mem_reg_size);
>>> +
>>> + guest_addr = 0x0;
>>
>>
>> Nit: Can't this be initialized where it's defined above ?
>
>
> I don't have a strong preference. Is it generally initialized on
> definition on kvm (selftests or not) code?
>
>
Some places do it where the variable is defined. For example, in smm_test.c,
vm_vaddr_t vmx_pages_gva = 0;
It reduces an extra line.
>>
>>
>>> +
>>> + /* Check it can be added memory slots up to the maximum allowed */
>>> + pr_info("Adding slots 0..%i, each memory region with %ldK size\n",
>>> + (max_mem_slots - 1), mem_reg_size >> 10);
>>> + for (slot = 0; slot < max_mem_slots; slot++) {
>>> + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
>>> + guest_addr, slot, mem_reg_npages,
>>> + 0);
>>> + guest_addr += mem_reg_size;
>>> + }
>>> +
>>> + /* Check it cannot be added memory slots beyond the limit */
>>> + mem = mmap(NULL, mem_reg_size, PROT_READ | PROT_WRITE,
>>> + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
>>> + TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
>>> +
>>> + ret = ioctl(vm_get_fd(vm), KVM_SET_USER_MEMORY_REGION,
>>> + &(struct kvm_userspace_memory_region) {slot, 0,
>>> guest_addr,
>>> + mem_reg_size, (uint64_t) mem});
>>> + TEST_ASSERT(ret == -1 && errno == EINVAL,
>>> + "Adding one more memory slot should fail with EINVAL");
>>
>>
>> Why not add a test here for adding memory at an existing slot ?
>
> Good question.
>
> I'm working on another test which should check it cannot be added
> overlapping slots. I will send it in a separate patch series,
> depending on the fate of this one. :)
>
> More precisely, those are the cases I will cover on this new test:
>
>
> 0x100000 0x300000
> 0x0 0x200000 0x400000
> slot0 | |---2MB--| (SUCCESS)
> slot1 |---2MB--| (FAIL)
> slot2 |---2MB--| (SUCCESS)
> slot3 |---2MB--| (FAIL)
> slot4 |---2MB--| (FAIL)
> slot5 |---2MB--| (SUCCESS)
>
> Thanks!
>
> Wainer
OK.
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@...cle.com>
>
>>
>>
>>> +
>>> + munmap(mem, mem_reg_size);
>>> + kvm_vm_free(vm);
>>> +}
>>> +
>>> +int main(int argc, char *argv[])
>>> +{
>>> + test_add_max_slots();
>>> + return 0;
>>> +}
>>
>
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