Introduce macro for performing MEM_OP ioctls in a concise way. Split test cases into multiple host/guest pairs making them independent. Make various minor improvements. All in all this lays the groundwork for future extensions.
Signed-off-by: Janis Schoetterl-Glausch scgl@linux.ibm.com --- tools/testing/selftests/kvm/s390x/memop.c | 427 ++++++++++++++++------ 1 file changed, 309 insertions(+), 118 deletions(-)
diff --git a/tools/testing/selftests/kvm/s390x/memop.c b/tools/testing/selftests/kvm/s390x/memop.c index d19c3ffdea3f..4510418d73e6 100644 --- a/tools/testing/selftests/kvm/s390x/memop.c +++ b/tools/testing/selftests/kvm/s390x/memop.c @@ -13,169 +13,360 @@ #include "test_util.h" #include "kvm_util.h"
+enum mop_target { + LOGICAL, + SIDA, + ABSOLUTE, + INVALID, +}; + +enum mop_access_mode { + READ, + WRITE, +}; + +struct mop_desc { + uintptr_t gaddr; + uintptr_t gaddr_v; + uint64_t set_flags; + unsigned int f_check : 1; + unsigned int f_inject : 1; + unsigned int f_key : 1; + unsigned int _gaddr_v : 1; + unsigned int _set_flags : 1; + unsigned int _sida_offset : 1; + unsigned int _ar : 1; + uint32_t size; + enum mop_target target; + enum mop_access_mode mode; + void *buf; + uint32_t sida_offset; + uint8_t ar; + uint8_t key; +}; + +static struct kvm_s390_mem_op ksmo_from_desc(struct mop_desc desc) +{ + struct kvm_s390_mem_op ksmo = { + .gaddr = (uintptr_t)desc.gaddr, + .size = desc.size, + .buf = ((uintptr_t)desc.buf), + .reserved = "ignored_ignored_ignored_ignored" + }; + + switch (desc.target) { + case LOGICAL: + if (desc.mode == READ) + ksmo.op = KVM_S390_MEMOP_LOGICAL_READ; + if (desc.mode == WRITE) + ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; + break; + case SIDA: + if (desc.mode == READ) + ksmo.op = KVM_S390_MEMOP_SIDA_READ; + if (desc.mode == WRITE) + ksmo.op = KVM_S390_MEMOP_SIDA_WRITE; + break; + case ABSOLUTE: + if (desc.mode == READ) + ksmo.op = KVM_S390_MEMOP_ABSOLUTE_READ; + if (desc.mode == WRITE) + ksmo.op = KVM_S390_MEMOP_ABSOLUTE_WRITE; + break; + case INVALID: + ksmo.op = -1; + } + if (desc.f_check) + ksmo.flags |= KVM_S390_MEMOP_F_CHECK_ONLY; + if (desc.f_inject) + ksmo.flags |= KVM_S390_MEMOP_F_INJECT_EXCEPTION; + if (desc._set_flags) + ksmo.flags = desc.set_flags; + if (desc.f_key) { + ksmo.flags |= KVM_S390_MEMOP_F_SKEY_PROTECTION; + ksmo.key = desc.key; + } + if (desc._ar) + ksmo.ar = desc.ar; + else + ksmo.ar = 0; + if (desc._sida_offset) + ksmo.sida_offset = desc.sida_offset; + + return ksmo; +} + +/* vcpu dummy id signifying that vm instead of vcpu ioctl is to occur */ +const uint32_t VM_VCPU_ID = (uint32_t)-1; + +struct test_vcpu { + struct kvm_vm *vm; + uint32_t id; +}; + +#define PRINT_MEMOP false +static void print_memop(uint32_t vcpu_id, const struct kvm_s390_mem_op *ksmo) +{ + if (!PRINT_MEMOP) + return; + + if (vcpu_id == VM_VCPU_ID) + printf("vm memop("); + else + printf("vcpu memop("); + switch (ksmo->op) { + case KVM_S390_MEMOP_LOGICAL_READ: + printf("LOGICAL, READ, "); + break; + case KVM_S390_MEMOP_LOGICAL_WRITE: + printf("LOGICAL, WRITE, "); + break; + case KVM_S390_MEMOP_SIDA_READ: + printf("SIDA, READ, "); + break; + case KVM_S390_MEMOP_SIDA_WRITE: + printf("SIDA, WRITE, "); + break; + case KVM_S390_MEMOP_ABSOLUTE_READ: + printf("ABSOLUTE, READ, "); + break; + case KVM_S390_MEMOP_ABSOLUTE_WRITE: + printf("ABSOLUTE, WRITE, "); + break; + } + printf("gaddr=%llu, size=%u, buf=%llu, ar=%u, key=%u", + ksmo->gaddr, ksmo->size, ksmo->buf, ksmo->ar, ksmo->key); + if (ksmo->flags & KVM_S390_MEMOP_F_CHECK_ONLY) + printf(", CHECK_ONLY"); + if (ksmo->flags & KVM_S390_MEMOP_F_INJECT_EXCEPTION) + printf(", INJECT_EXCEPTION"); + if (ksmo->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) + printf(", SKEY_PROTECTION"); + puts(")"); +} + +static void memop_ioctl(struct test_vcpu vcpu, struct kvm_s390_mem_op *ksmo) +{ + if (vcpu.id == VM_VCPU_ID) + vm_ioctl(vcpu.vm, KVM_S390_MEM_OP, ksmo); + else + vcpu_ioctl(vcpu.vm, vcpu.id, KVM_S390_MEM_OP, ksmo); +} + +static int err_memop_ioctl(struct test_vcpu vcpu, struct kvm_s390_mem_op *ksmo) +{ + if (vcpu.id == VM_VCPU_ID) + return _vm_ioctl(vcpu.vm, KVM_S390_MEM_OP, ksmo); + else + return _vcpu_ioctl(vcpu.vm, vcpu.id, KVM_S390_MEM_OP, ksmo); +} + +#define MEMOP(err, vcpu_p, mop_target_p, access_mode_p, buf_p, size_p, ...) \ +({ \ + struct test_vcpu __vcpu = (vcpu_p); \ + struct mop_desc __desc = { \ + .target = (mop_target_p), \ + .mode = (access_mode_p), \ + .buf = (buf_p), \ + .size = (size_p), \ + __VA_ARGS__ \ + }; \ + struct kvm_s390_mem_op __ksmo; \ + \ + if (__desc._gaddr_v) { \ + if (__desc.target == ABSOLUTE) \ + __desc.gaddr = addr_gva2gpa(__vcpu.vm, __desc.gaddr_v); \ + else \ + __desc.gaddr = __desc.gaddr_v; \ + } \ + __ksmo = ksmo_from_desc(__desc); \ + print_memop(__vcpu.id, &__ksmo); \ + err##memop_ioctl(__vcpu, &__ksmo); \ +}) + +#define MOP(...) MEMOP(, __VA_ARGS__) +#define ERR_MOP(...) MEMOP(err_, __VA_ARGS__) + +#define GADDR(a) .gaddr = ((uintptr_t)a) +#define GADDR_V(v) ._gaddr_v = 1, .gaddr_v = ((uintptr_t)v) +#define CHECK_ONLY .f_check = 1 +#define SET_FLAGS(f) ._set_flags = 1, .set_flags = (f) +#define SIDA_OFFSET(o) ._sida_offset = 1, .sida_offset = (o) +#define AR(a) ._ar = 1, .ar = (a) +#define KEY(a) .f_key = 1, .key = (a) + +#define CHECK_N_DO(f, ...) ({ f(__VA_ARGS__, CHECK_ONLY); f(__VA_ARGS__); }) + #define VCPU_ID 1 +#define PAGE_SHIFT 12 +#define PAGE_SIZE (1ULL << PAGE_SHIFT) +#define PAGE_MASK (~(PAGE_SIZE - 1)) + +#define ASSERT_MEM_EQ(p1, p2, size) \ + TEST_ASSERT(!memcmp(p1, p2, size), "Memory contents do not match!")
static uint8_t mem1[65536]; static uint8_t mem2[65536];
-static void guest_code(void) +static void prepare_mem12(void) { int i;
- for (;;) { - for (i = 0; i < sizeof(mem2); i++) - mem2[i] = mem1[i]; - GUEST_SYNC(0); - } + for (i = 0; i < sizeof(mem1); i++) + mem1[i] = rand(); + memset(mem2, 0xaa, sizeof(mem2)); }
-int main(int argc, char *argv[]) -{ - struct kvm_vm *vm; +struct test_default { + struct test_vcpu vm; + struct test_vcpu vcpu; struct kvm_run *run; - struct kvm_s390_mem_op ksmo; - int rv, i, maxsize; + int size; +};
- setbuf(stdout, NULL); /* Tell stdout not to buffer its content */ +static struct test_default test_default_init(void *guest_code) +{ + struct test_default t;
- maxsize = kvm_check_cap(KVM_CAP_S390_MEM_OP); - if (!maxsize) { - print_skip("CAP_S390_MEM_OP not supported"); - exit(KSFT_SKIP); - } - if (maxsize > sizeof(mem1)) - maxsize = sizeof(mem1); + t.size = min((size_t)kvm_check_cap(KVM_CAP_S390_MEM_OP), sizeof(mem1)); + t.vm = (struct test_vcpu) { vm_create_default(VCPU_ID, 0, guest_code), VM_VCPU_ID }; + t.vcpu = (struct test_vcpu) { t.vm.vm, VCPU_ID }; + t.run = vcpu_state(t.vm.vm, VCPU_ID); + return t; +}
- /* Create VM */ - vm = vm_create_default(VCPU_ID, 0, guest_code); - run = vcpu_state(vm, VCPU_ID); +static void test_vm_free(struct test_vcpu vm) +{ + kvm_vm_free(vm.vm); +}
- for (i = 0; i < sizeof(mem1); i++) - mem1[i] = i * i + i; - - /* Set the first array */ - ksmo.gaddr = addr_gva2gpa(vm, (uintptr_t)mem1); - ksmo.flags = 0; - ksmo.size = maxsize; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 0; - vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); - - /* Let the guest code copy the first array to the second */ - vcpu_run(vm, VCPU_ID); - TEST_ASSERT(run->exit_reason == KVM_EXIT_S390_SIEIC, - "Unexpected exit reason: %u (%s)\n", - run->exit_reason, - exit_reason_str(run->exit_reason)); +#define HOST_SYNC(vcpu_p, stage) \ +({ \ + struct test_vcpu __vcpu = (vcpu_p); \ + struct ucall uc; \ + int __stage = (stage); \ + \ + vcpu_run(__vcpu.vm, __vcpu.id); \ + get_ucall(__vcpu.vm, __vcpu.id, &uc); \ + ASSERT_EQ(uc.cmd, UCALL_SYNC); \ + ASSERT_EQ(uc.args[1], __stage); \ +}) \
- memset(mem2, 0xaa, sizeof(mem2)); +enum stage { + /* Synced state set by host, e.g. DAT */ + STAGE_INITED, + /* Guest did nothing */ + STAGE_IDLED, + /* Guest copied memory (locations up to test case) */ + STAGE_COPIED, +}; + +#define DEFAULT_WRITE_READ(copy_cpu, mop_cpu, mop_target_p, size, ...) \ +({ \ + struct test_vcpu __copy_cpu = (copy_cpu), __mop_cpu = (mop_cpu); \ + enum mop_target __target = (mop_target_p); \ + uint32_t __size = (size); \ + \ + prepare_mem12(); \ + CHECK_N_DO(MOP, __mop_cpu, __target, WRITE, mem1, __size, \ + GADDR_V(mem1), ##__VA_ARGS__); \ + HOST_SYNC(__copy_cpu, STAGE_COPIED); \ + CHECK_N_DO(MOP, __mop_cpu, __target, READ, mem2, __size, \ + GADDR_V(mem2), ##__VA_ARGS__); \ + ASSERT_MEM_EQ(mem1, mem2, __size); \ +}) + +static void guest_copy(void) +{ + GUEST_SYNC(STAGE_INITED); + memcpy(&mem2, &mem1, sizeof(mem2)); + GUEST_SYNC(STAGE_COPIED); +} + +static void test_copy(void) +{ + struct test_default t = test_default_init(guest_copy); + + HOST_SYNC(t.vcpu, STAGE_INITED); + + DEFAULT_WRITE_READ(t.vcpu, t.vcpu, LOGICAL, t.size); + + test_vm_free(t.vm); +}
- /* Get the second array */ - ksmo.gaddr = (uintptr_t)mem2; - ksmo.flags = 0; - ksmo.size = maxsize; - ksmo.op = KVM_S390_MEMOP_LOGICAL_READ; - ksmo.buf = (uintptr_t)mem2; - ksmo.ar = 0; - vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); - - TEST_ASSERT(!memcmp(mem1, mem2, maxsize), - "Memory contents do not match!"); - - /* Check error conditions - first bad size: */ - ksmo.gaddr = (uintptr_t)mem1; - ksmo.flags = 0; - ksmo.size = -1; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); +static void guest_idle(void) +{ + GUEST_SYNC(STAGE_INITED); + for (;;) + GUEST_SYNC(STAGE_IDLED); +} + +static void test_errors(void) +{ + struct test_default t = test_default_init(guest_idle); + int rv; + + HOST_SYNC(t.vcpu, STAGE_INITED); + + rv = ERR_MOP(t.vcpu, LOGICAL, WRITE, mem1, -1, GADDR_V(mem1)); TEST_ASSERT(rv == -1 && errno == E2BIG, "ioctl allows insane sizes");
/* Zero size: */ - ksmo.gaddr = (uintptr_t)mem1; - ksmo.flags = 0; - ksmo.size = 0; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, LOGICAL, WRITE, mem1, 0, GADDR_V(mem1)); TEST_ASSERT(rv == -1 && (errno == EINVAL || errno == ENOMEM), "ioctl allows 0 as size");
/* Bad flags: */ - ksmo.gaddr = (uintptr_t)mem1; - ksmo.flags = -1; - ksmo.size = maxsize; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, LOGICAL, WRITE, mem1, t.size, GADDR_V(mem1), SET_FLAGS(-1)); TEST_ASSERT(rv == -1 && errno == EINVAL, "ioctl allows all flags");
/* Bad operation: */ - ksmo.gaddr = (uintptr_t)mem1; - ksmo.flags = 0; - ksmo.size = maxsize; - ksmo.op = -1; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, INVALID, WRITE, mem1, t.size, GADDR_V(mem1)); TEST_ASSERT(rv == -1 && errno == EINVAL, "ioctl allows bad operations");
/* Bad guest address: */ - ksmo.gaddr = ~0xfffUL; - ksmo.flags = KVM_S390_MEMOP_F_CHECK_ONLY; - ksmo.size = maxsize; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, LOGICAL, WRITE, mem1, t.size, GADDR((void *)~0xfffUL), CHECK_ONLY); TEST_ASSERT(rv > 0, "ioctl does not report bad guest memory access");
/* Bad host address: */ - ksmo.gaddr = (uintptr_t)mem1; - ksmo.flags = 0; - ksmo.size = maxsize; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = 0; - ksmo.ar = 0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, LOGICAL, WRITE, 0, t.size, GADDR_V(mem1)); TEST_ASSERT(rv == -1 && errno == EFAULT, "ioctl does not report bad host memory address");
/* Bad access register: */ - run->psw_mask &= ~(3UL << (63 - 17)); - run->psw_mask |= 1UL << (63 - 17); /* Enable AR mode */ - vcpu_run(vm, VCPU_ID); /* To sync new state to SIE block */ - ksmo.gaddr = (uintptr_t)mem1; - ksmo.flags = 0; - ksmo.size = maxsize; - ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; - ksmo.buf = (uintptr_t)mem1; - ksmo.ar = 17; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + t.run->psw_mask &= ~(3UL << (63 - 17)); + t.run->psw_mask |= 1UL << (63 - 17); /* Enable AR mode */ + HOST_SYNC(t.vcpu, STAGE_IDLED); + rv = ERR_MOP(t.vcpu, LOGICAL, WRITE, mem1, t.size, GADDR(mem1), AR(17)); TEST_ASSERT(rv == -1 && errno == EINVAL, "ioctl allows ARs > 15"); - run->psw_mask &= ~(3UL << (63 - 17)); /* Disable AR mode */ - vcpu_run(vm, VCPU_ID); /* Run to sync new state */ + t.run->psw_mask &= ~(3UL << (63 - 17)); /* Disable AR mode */ + HOST_SYNC(t.vcpu, STAGE_IDLED);
/* Check that the SIDA calls are rejected for non-protected guests */ - ksmo.gaddr = 0; - ksmo.flags = 0; - ksmo.size = 8; - ksmo.op = KVM_S390_MEMOP_SIDA_READ; - ksmo.buf = (uintptr_t)mem1; - ksmo.sida_offset = 0x1c0; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, SIDA, READ, mem1, 8, GADDR(0), SIDA_OFFSET(0x1c0)); TEST_ASSERT(rv == -1 && errno == EINVAL, "ioctl does not reject SIDA_READ in non-protected mode"); - ksmo.op = KVM_S390_MEMOP_SIDA_WRITE; - rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo); + rv = ERR_MOP(t.vcpu, SIDA, WRITE, mem1, 8, GADDR(0), SIDA_OFFSET(0x1c0)); TEST_ASSERT(rv == -1 && errno == EINVAL, "ioctl does not reject SIDA_WRITE in non-protected mode");
- kvm_vm_free(vm); + test_vm_free(t.vm); +} + +int main(int argc, char *argv[]) +{ + int memop_cap; + + setbuf(stdout, NULL); /* Tell stdout not to buffer its content */ + + memop_cap = kvm_check_cap(KVM_CAP_S390_MEM_OP); + if (!memop_cap) { + print_skip("CAP_S390_MEM_OP not supported"); + exit(KSFT_SKIP); + } + + test_copy(); + test_errors();
return 0; }
On 2/17/22 7:53 AM, Janis Schoetterl-Glausch wrote:
Introduce macro for performing MEM_OP ioctls in a concise way.
How does this help? What is the value in re-writing existing code and turning it into a macro?
Split test cases into multiple host/guest pairs making them independent.
This is a good change.
Make various minor improvements. All in all this lays the groundwork for future extensions.
Also good if these changes make it easier to add test. Would be helpful to know the details of the groundwork.
thanks, -- Shuah
On 2/17/22 18:36, Shuah Khan wrote:
On 2/17/22 7:53 AM, Janis Schoetterl-Glausch wrote:
Introduce macro for performing MEM_OP ioctls in a concise way.
How does this help? What is the value in re-writing existing code and turning it into a macro?
I want invocations of the ioctl to be independent of each other, so the reader does not have to keep track of the state of the struct kvm_s390_mem_op.
So you have to specify all arguments manually like so, which is rather noisy and makes it hard to see what the relevant parameter is:
ksmo.gaddr = guest_mem1; ksmo.flags = 0; ksmo.size = maxsize; ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; ksmo.buf = (uintptr_t)mem1; ksmo.ar = 17; rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo);
Or you introduce an abstraction. Previously I used lots of functions with repeated code which got chaotic. I decided on the macro because it's more flexible, e.g. you don't have to pass default args. For example, there is only one test that passes the access register arg, so you would want to default it to 0 for all other test. For the access key argument you need to pass both a flag and the key itself, so you'd probably get rid of this redundancy also. There also might be future extensions of the ioctl that work the same way (not 100% but not purely theoretical either).
With the macro all that is orthogonal, you just pass the argument you need or you don't. With functions you'd maybe add a memop_key() variant and a _ar() variant and a _key_ar() variant if you need it (currently not necessary), doubling the number of functions with each additional argument. Another example is GADDR_V and GADDR, the first takes care of translating the address to an physical one, but sometimes you need to pass it untranslated, and we need to combine that with passing a key or not.
A big improvement was making the target of the ioctl (vm/vcpu) and the operation arguments instead of baking it into the function. Since they're mandatory arguments this is independent of the macro vs functions question.
In the end there are multiple independent but interacting improvements and it is kinda hard to make the call on how far to go along one dimension, e.g. I was unsure if I wanted to introduce the DEFAULT_READ macro, but decided for it, since, as a reviewer, you can see that it executes the same code with different arguments, instead of trying to identify the difference between 5 copy-pasted and modified lines of code. On the other hand you have the cost of introducing an indirection.
Split test cases into multiple host/guest pairs making them independent.
This is a good change.
Make various minor improvements. All in all this lays the groundwork for future extensions.
Also good if these changes make it easier to add test. Would be helpful to know the details of the groundwork.
Yeah I'm not too happy about the commit descriptions. I was unsure how to structure the patches, since the new test motivate the restructuring, e.g. if I put the _test_errors_common in the first patch it's kinda weird since at that stage there is no commonality at all. I ended up moving stuff around + since I'm not quite sure about stuff like the DEFAULT_ macros I left the description kinda vague.
Probably should have linked to the series this is a reply to, since linux-kselftest wasn't on cc: https://lore.kernel.org/kvm/20220211182215.2730017-1-scgl@linux.ibm.com/
thanks, -- Shuah
On 2/18/22 5:09 AM, Janis Schoetterl-Glausch wrote:
On 2/17/22 18:36, Shuah Khan wrote:
On 2/17/22 7:53 AM, Janis Schoetterl-Glausch wrote:
Introduce macro for performing MEM_OP ioctls in a concise way.
How does this help? What is the value in re-writing existing code and turning it into a macro?
I want invocations of the ioctl to be independent of each other, so the reader does not have to keep track of the state of the struct kvm_s390_mem_op.
So you have to specify all arguments manually like so, which is rather noisy and makes it hard to see what the relevant parameter is:
ksmo.gaddr = guest_mem1; ksmo.flags = 0; ksmo.size = maxsize; ksmo.op = KVM_S390_MEMOP_LOGICAL_WRITE; ksmo.buf = (uintptr_t)mem1; ksmo.ar = 17; rv = _vcpu_ioctl(vm, VCPU_ID, KVM_S390_MEM_OP, &ksmo);
Or you introduce an abstraction. Previously I used lots of functions with repeated code which got chaotic. I decided on the macro because it's more flexible, e.g. you don't have to pass default args. For example, there is only one test that passes the access register arg, so you would want to default it to 0 for all other test. For the access key argument you need to pass both a flag and the key itself, so you'd probably get rid of this redundancy also. There also might be future extensions of the ioctl that work the same way (not 100% but not purely theoretical either).
With the macro all that is orthogonal, you just pass the argument you need or you don't. With functions you'd maybe add a memop_key() variant and a _ar() variant and a _key_ar() variant if you need it (currently not necessary), doubling the number of functions with each additional argument. Another example is GADDR_V and GADDR, the first takes care of translating the address to an physical one, but sometimes you need to pass it untranslated, and we need to combine that with passing a key or not.
A big improvement was making the target of the ioctl (vm/vcpu) and the operation arguments instead of baking it into the function. Since they're mandatory arguments this is independent of the macro vs functions question.
In the end there are multiple independent but interacting improvements and it is kinda hard to make the call on how far to go along one dimension, e.g. I was unsure if I wanted to introduce the DEFAULT_READ macro, but decided for it, since, as a reviewer, you can see that it executes the same code with different arguments, instead of trying to identify the difference between 5 copy-pasted and modified lines of code. On the other hand you have the cost of introducing an indirection.
Sounds good. I am not fan of macros, however, in this case macro helps. Please split the patches so that restructuring work is done first and then the new code - as per my suggestion on the second patch.
thanks, -- Shuah
linux-kselftest-mirror@lists.linaro.org
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Janis Schoetterl-Glausch -
Shuah Khan