On 2021/3/12 19:14, Andrew Jones wrote:

On Tue, Mar 02, 2021 at 08:57:44PM +0800, Yanan Wang wrote:

...

We know that if a system supports multiple hugetlb page sizes, the desired hugetlb page size can be specified in bits [26:31] of the flag arguments. The value in these 6 bits will be the shift of each hugetlb page size.

So add a macro to get the page size shift and then calculate the corresponding hugetlb page size, using flag x.

Cc: Ben Gardon bgardon@google.com Cc: Ingo Molnar mingo@kernel.org Cc: Adrian Hunter adrian.hunter@intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Arnd Bergmann arnd@arndb.de Cc: Michael Kerrisk mtk.manpages@gmail.com Cc: Thomas Gleixner tglx@linutronix.de Suggested-by: Ben Gardon bgardon@google.com Signed-off-by: Yanan Wang wangyanan55@huawei.com Reviewed-by: Ben Gardon bgardon@google.com

---

include/uapi/linux/mman.h | 2 ++ tools/include/uapi/linux/mman.h | 2 ++ 2 files changed, 4 insertions(+)

diff --git a/include/uapi/linux/mman.h b/include/uapi/linux/mman.h index f55bc680b5b0..8bd41128a0ee 100644 --- a/include/uapi/linux/mman.h +++ b/include/uapi/linux/mman.h @@ -41,4 +41,6 @@ #define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB #define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB +#define MAP_HUGE_PAGE_SIZE(x) (1 << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))

Needs to be '1ULL' to avoid shift overflow when given MAP_HUGE_16GB.

Thanks, drew. Will fix it.

Thanks, drew

...

• #endif /* _UAPI_LINUX_MMAN_H */

diff --git a/tools/include/uapi/linux/mman.h b/tools/include/uapi/linux/mman.h index f55bc680b5b0..8bd41128a0ee 100644 --- a/tools/include/uapi/linux/mman.h +++ b/tools/include/uapi/linux/mman.h @@ -41,4 +41,6 @@ #define MAP_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB #define MAP_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB +#define MAP_HUGE_PAGE_SIZE(x) (1 << ((x >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))

• #endif /* _UAPI_LINUX_MMAN_H */

-- 2.23.0

.

Hi Drew,

Thanks for your attention to this series! On 2021/3/12 19:31, Andrew Jones wrote:

On Tue, Mar 02, 2021 at 08:57:47PM +0800, Yanan Wang wrote:

...

If we want to have some tests about transparent hugepages, the system configured THP hugepage size should better be known by the tests, which can be used for kinds of alignment or guest memory accessing of vcpus... So it makes sense to add a helper to get the transparent hugepage size.

With VM_MEM_SRC_ANONYMOUS_THP specified in vm_userspace_mem_region_add(), we now stat /sys/kernel/mm/transparent_hugepage to check whether THP is configured in the host kernel before madvise(). Based on this, we can also read file /sys/kernel/mm/transparent_hugepage/hpage_pmd_size to get THP hugepage size.

Signed-off-by: Yanan Wang wangyanan55@huawei.com Reviewed-by: Ben Gardon bgardon@google.com

---

.../testing/selftests/kvm/include/test_util.h | 2 ++ tools/testing/selftests/kvm/lib/test_util.c | 36 +++++++++++++++++++ 2 files changed, 38 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index b7f41399f22c..ef24c76ba89a 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -78,6 +78,8 @@ struct vm_mem_backing_src_alias { enum vm_mem_backing_src_type type; }; +bool thp_configured(void); +size_t get_trans_hugepagesz(void); void backing_src_help(void); enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name); diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index c7c0627c6842..f2d133f76c67 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -10,6 +10,7 @@ #include <limits.h> #include <stdlib.h> #include <time.h> +#include <sys/stat.h> #include "linux/kernel.h" #include "test_util.h" @@ -117,6 +118,41 @@ const struct vm_mem_backing_src_alias backing_src_aliases[] = { {"anonymous_hugetlb", VM_MEM_SRC_ANONYMOUS_HUGETLB,}, }; +bool thp_configured(void) +{

• int ret;
• struct stat statbuf;
• ret = stat("/sys/kernel/mm/transparent_hugepage", &statbuf);
• TEST_ASSERT(ret == 0 || (ret == -1 && errno == ENOENT),

•     "Error in stating /sys/kernel/mm/transparent_hugepage: %d",
  

•     errno);
  

TEST_ASSERT will already output errno's string. Is that not sufficient? If not, I think extending TEST_ASSERT to output errno too would be fine.

I think it's a good idea to output the errno together with it's string in TEST_ASSERT, it will explicitly indicate that the string is an error information and the errno is much easier to be used for debugging than the string. I will make this change a separate patch in next version and add your S-b tag.

...

• return ret == 0;

+}

+size_t get_trans_hugepagesz(void) +{

• size_t size;
• char buf[16];
• FILE *f;
• TEST_ASSERT(thp_configured(), "THP is not configured in host kernel");
• f = fopen("/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", "r");
• TEST_ASSERT(f != NULL,

•     "Error in opening transparent_hugepage/hpage_pmd_size: %d",
  

•     errno);
  

Same comment as above.

...

• if (fread(buf, sizeof(char), sizeof(buf), f) == 0) {

• fclose(f);
  

• TEST_FAIL("Unable to read transparent_hugepage/hpage_pmd_size");
  

• }
• size = strtoull(buf, NULL, 10);

fscanf with %lld?

This makes senses. But it should be %ld corresponding to size_t.

Thanks, Yanan.

...

• return size;

+}

• void backing_src_help(void) { int i;

-- 2.23.0

Thanks, drew

.

On Tue, Mar 02, 2021 at 08:57:48PM +0800, Yanan Wang wrote:

If HUGETLB is configured in the host kernel, then we can know the system default hugetlb page size through *cat /proc/meminfo*. Otherwise, we will not see the information of hugetlb pages in file /proc/meminfo if it's not configured. So add a helper to determine whether HUGETLB is configured and then get the default page size by reading /proc/meminfo.

This helper can be useful when a program wants to use the default hugetlb pages of the system and doesn't know the default page size.

Signed-off-by: Yanan Wang wangyanan55@huawei.com

.../testing/selftests/kvm/include/test_util.h | 1 + tools/testing/selftests/kvm/lib/test_util.c | 27 +++++++++++++++++++ 2 files changed, 28 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index ef24c76ba89a..e087174eefe5 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -80,6 +80,7 @@ struct vm_mem_backing_src_alias { bool thp_configured(void); size_t get_trans_hugepagesz(void); +size_t get_def_hugetlb_pagesz(void); void backing_src_help(void); enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name); diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index f2d133f76c67..80d68dbd72d2 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -153,6 +153,33 @@ size_t get_trans_hugepagesz(void) return size; } +size_t get_def_hugetlb_pagesz(void) +{

• char buf[64];
• const char *tag = "Hugepagesize:";
• FILE *f;
• f = fopen("/proc/meminfo", "r");
• TEST_ASSERT(f != NULL, "Error in opening /proc/meminfo: %d", errno);
• while (fgets(buf, sizeof(buf), f) != NULL) {

• if (strstr(buf, tag) == buf) {
  

• 	fclose(f);
  

• 	return strtoull(buf + strlen(tag), NULL, 10) << 10;
  

• }
  

• }
• if (feof(f)) {

• fclose(f);
  

• TEST_FAIL("HUGETLB is not configured in host kernel");
  

• } else {

• fclose(f);
  

• TEST_FAIL("Error in reading /proc/meminfo: %d", errno);
  

• }

fclose() can be factored out.

• return 0;

+}

void backing_src_help(void) { int i; -- 2.23.0

Besides the fclose comment and the same errno comment as the previous patch

Reviewed-by: Andrew Jones drjones@redhat.com

On 2021/3/12 19:49, Andrew Jones wrote:

On Tue, Mar 02, 2021 at 08:57:49PM +0800, Yanan Wang wrote:

...

With VM_MEM_SRC_ANONYMOUS_HUGETLB, we currently can only use system default hugetlb pages to back the testing guest memory. In order to add flexibility, now list all the known hugetlb backing src types with different page sizes, so that we can specify use of hugetlb pages of the exact granularity that we want. And as all the known hugetlb page sizes are listed, it's appropriate for all architectures.

Besides, the helper get_backing_src_pagesz() is added to get the granularity of different backing src types(anonumous, thp, hugetlb).

Suggested-by: Ben Gardon bgardon@google.com Signed-off-by: Yanan Wang wangyanan55@huawei.com

---

.../testing/selftests/kvm/include/test_util.h | 18 +++++- tools/testing/selftests/kvm/lib/kvm_util.c | 2 +- tools/testing/selftests/kvm/lib/test_util.c | 59 +++++++++++++++---- 3 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index e087174eefe5..fade3130eb01 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -71,16 +71,32 @@ enum vm_mem_backing_src_type { VM_MEM_SRC_ANONYMOUS, VM_MEM_SRC_ANONYMOUS_THP, VM_MEM_SRC_ANONYMOUS_HUGETLB,

• VM_MEM_SRC_ANONYMOUS_HUGETLB_16KB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_64KB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_512KB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_1MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_2MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_8MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_16MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_32MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_256MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_512MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_1GB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_2GB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB,
• NUM_SRC_TYPES, };

struct vm_mem_backing_src_alias { const char *name;

• enum vm_mem_backing_src_type type;

• uint32_t flag; };

bool thp_configured(void); size_t get_trans_hugepagesz(void); size_t get_def_hugetlb_pagesz(void); +const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i); +size_t get_backing_src_pagesz(uint32_t i); void backing_src_help(void); enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name); diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index cc22c4ab7d67..b91c8e3a7ee1 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -757,7 +757,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, region->mmap_start = mmap(NULL, region->mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS

• 		  | (src_type == VM_MEM_SRC_ANONYMOUS_HUGETLB ? MAP_HUGETLB : 0),
  

• 		  | vm_mem_backing_src_alias(src_type)->flag,
  	  -1, 0);
  

  TEST_ASSERT(region->mmap_start != MAP_FAILED, "test_malloc failed, mmap_start: %p errno: %i",

diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index 80d68dbd72d2..df8a42eff1f8 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -11,6 +11,7 @@ #include <stdlib.h> #include <time.h> #include <sys/stat.h> +#include <linux/mman.h> #include "linux/kernel.h" #include "test_util.h" @@ -112,12 +113,6 @@ void print_skip(const char *fmt, ...) puts(", skipping test"); } -const struct vm_mem_backing_src_alias backing_src_aliases[] = {

• {"anonymous", VM_MEM_SRC_ANONYMOUS,},
• {"anonymous_thp", VM_MEM_SRC_ANONYMOUS_THP,},
• {"anonymous_hugetlb", VM_MEM_SRC_ANONYMOUS_HUGETLB,},

-};

• bool thp_configured(void) { int ret;

@@ -180,22 +175,64 @@ size_t get_def_hugetlb_pagesz(void) return 0; } +const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i) +{

• static const struct vm_mem_backing_src_alias aliases[] = {

• { "anonymous",               0                            },
  

• { "anonymous_thp",           0                            },
  

• { "anonymous_hugetlb",       MAP_HUGETLB                  },
  

• { "anonymous_hugetlb_16kb",  MAP_HUGETLB | MAP_HUGE_16KB  },
  

• { "anonymous_hugetlb_64kb",  MAP_HUGETLB | MAP_HUGE_64KB  },
  

• { "anonymous_hugetlb_512kb", MAP_HUGETLB | MAP_HUGE_512KB },
  

• { "anonymous_hugetlb_1mb",   MAP_HUGETLB | MAP_HUGE_1MB   },
  

• { "anonymous_hugetlb_2mb",   MAP_HUGETLB | MAP_HUGE_2MB   },
  

• { "anonymous_hugetlb_8mb",   MAP_HUGETLB | MAP_HUGE_8MB   },
  

• { "anonymous_hugetlb_16mb",  MAP_HUGETLB | MAP_HUGE_16MB  },
  

• { "anonymous_hugetlb_32mb",  MAP_HUGETLB | MAP_HUGE_32MB  },
  

• { "anonymous_hugetlb_256mb", MAP_HUGETLB | MAP_HUGE_256MB },
  

• { "anonymous_hugetlb_512mb", MAP_HUGETLB | MAP_HUGE_512MB },
  

• { "anonymous_hugetlb_1gb",   MAP_HUGETLB | MAP_HUGE_1GB   },
  

• { "anonymous_hugetlb_2gb",   MAP_HUGETLB | MAP_HUGE_2GB   },
  

• { "anonymous_hugetlb_16gb",  MAP_HUGETLB | MAP_HUGE_16GB  },
  

• };
• _Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES,

•        "Missing new backing src types?");
  

• TEST_ASSERT(i < NUM_SRC_TYPES, "Backing src type ID %d too big", i);
• return &aliases[i];

+}

+size_t get_backing_src_pagesz(uint32_t i) +{

• uint32_t flag = vm_mem_backing_src_alias(i)->flag;
• if (i == VM_MEM_SRC_ANONYMOUS)

• return getpagesize();
  

• if (i == VM_MEM_SRC_ANONYMOUS_THP)

• return get_trans_hugepagesz();
  

• if (i == VM_MEM_SRC_ANONYMOUS_HUGETLB)

• return get_def_hugetlb_pagesz();
  

nit: a switch would look nicer (IMHO)

Ok, will change.

...

• return MAP_HUGE_PAGE_SIZE(flag);

+}

• void backing_src_help(void) { int i;

printf("Available backing src types:\n");

• for (i = 0; i < ARRAY_SIZE(backing_src_aliases); i++)

• printf("\t%s\n", backing_src_aliases[i].name);
  

• for (i = 0; i < NUM_SRC_TYPES; i++)
  

• 	printf("\t%s\n", vm_mem_backing_src_alias(i)->name);
  

What happened with the indentation here?

Thanks for pointing out this. It was a stupid mistake, I will fix it.

...

} enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name) { int i;

• for (i = 0; i < ARRAY_SIZE(backing_src_aliases); i++)

• if (!strcmp(type_name, backing_src_aliases[i].name))
  

• 	return backing_src_aliases[i].type;
  

• for (i = 0; i < NUM_SRC_TYPES; i++)

• if (!strcmp(type_name, vm_mem_backing_src_alias(i)->name))
  

• 	return i;
  

backing_src_help(); TEST_FAIL("Unknown backing src type: %s", type_name); -- 2.23.0

Otherwise

Reviewed-by: Andrew Jones drjones@redhat.com

Thanks, Yanan

.

On 2021/3/12 20:02, Andrew Jones wrote:

On Tue, Mar 02, 2021 at 08:57:49PM +0800, Yanan Wang wrote:

...

With VM_MEM_SRC_ANONYMOUS_HUGETLB, we currently can only use system default hugetlb pages to back the testing guest memory. In order to add flexibility, now list all the known hugetlb backing src types with different page sizes, so that we can specify use of hugetlb pages of the exact granularity that we want. And as all the known hugetlb page sizes are listed, it's appropriate for all architectures.

Besides, the helper get_backing_src_pagesz() is added to get the granularity of different backing src types(anonumous, thp, hugetlb).

Suggested-by: Ben Gardon bgardon@google.com Signed-off-by: Yanan Wang wangyanan55@huawei.com

---

.../testing/selftests/kvm/include/test_util.h | 18 +++++- tools/testing/selftests/kvm/lib/kvm_util.c | 2 +- tools/testing/selftests/kvm/lib/test_util.c | 59 +++++++++++++++---- 3 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index e087174eefe5..fade3130eb01 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -71,16 +71,32 @@ enum vm_mem_backing_src_type { VM_MEM_SRC_ANONYMOUS, VM_MEM_SRC_ANONYMOUS_THP, VM_MEM_SRC_ANONYMOUS_HUGETLB,

• VM_MEM_SRC_ANONYMOUS_HUGETLB_16KB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_64KB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_512KB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_1MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_2MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_8MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_16MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_32MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_256MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_512MB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_1GB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_2GB,
• VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB,
• NUM_SRC_TYPES, };

struct vm_mem_backing_src_alias { const char *name;

• enum vm_mem_backing_src_type type;

• uint32_t flag; };

bool thp_configured(void); size_t get_trans_hugepagesz(void); size_t get_def_hugetlb_pagesz(void); +const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i); +size_t get_backing_src_pagesz(uint32_t i); void backing_src_help(void); enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name); diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index cc22c4ab7d67..b91c8e3a7ee1 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -757,7 +757,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, region->mmap_start = mmap(NULL, region->mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS

• 		  | (src_type == VM_MEM_SRC_ANONYMOUS_HUGETLB ? MAP_HUGETLB : 0),
  

• 		  | vm_mem_backing_src_alias(src_type)->flag,
  	  -1, 0);
  

  TEST_ASSERT(region->mmap_start != MAP_FAILED, "test_malloc failed, mmap_start: %p errno: %i",

diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index 80d68dbd72d2..df8a42eff1f8 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -11,6 +11,7 @@ #include <stdlib.h> #include <time.h> #include <sys/stat.h> +#include <linux/mman.h> #include "linux/kernel.h" #include "test_util.h" @@ -112,12 +113,6 @@ void print_skip(const char *fmt, ...) puts(", skipping test"); } -const struct vm_mem_backing_src_alias backing_src_aliases[] = {

• {"anonymous", VM_MEM_SRC_ANONYMOUS,},
• {"anonymous_thp", VM_MEM_SRC_ANONYMOUS_THP,},
• {"anonymous_hugetlb", VM_MEM_SRC_ANONYMOUS_HUGETLB,},

-};

• bool thp_configured(void) { int ret;

@@ -180,22 +175,64 @@ size_t get_def_hugetlb_pagesz(void) return 0; } +const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i) +{

• static const struct vm_mem_backing_src_alias aliases[] = {

• { "anonymous",               0                            },
  

• { "anonymous_thp",           0                            },
  

• { "anonymous_hugetlb",       MAP_HUGETLB                  },
  

• { "anonymous_hugetlb_16kb",  MAP_HUGETLB | MAP_HUGE_16KB  },
  

• { "anonymous_hugetlb_64kb",  MAP_HUGETLB | MAP_HUGE_64KB  },
  

• { "anonymous_hugetlb_512kb", MAP_HUGETLB | MAP_HUGE_512KB },
  

• { "anonymous_hugetlb_1mb",   MAP_HUGETLB | MAP_HUGE_1MB   },
  

• { "anonymous_hugetlb_2mb",   MAP_HUGETLB | MAP_HUGE_2MB   },
  

• { "anonymous_hugetlb_8mb",   MAP_HUGETLB | MAP_HUGE_8MB   },
  

• { "anonymous_hugetlb_16mb",  MAP_HUGETLB | MAP_HUGE_16MB  },
  

• { "anonymous_hugetlb_32mb",  MAP_HUGETLB | MAP_HUGE_32MB  },
  

• { "anonymous_hugetlb_256mb", MAP_HUGETLB | MAP_HUGE_256MB },
  

• { "anonymous_hugetlb_512mb", MAP_HUGETLB | MAP_HUGE_512MB },
  

• { "anonymous_hugetlb_1gb",   MAP_HUGETLB | MAP_HUGE_1GB   },
  

• { "anonymous_hugetlb_2gb",   MAP_HUGETLB | MAP_HUGE_2GB   },
  

• { "anonymous_hugetlb_16gb",  MAP_HUGETLB | MAP_HUGE_16GB  },
  

• };
• _Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES,

•        "Missing new backing src types?");
  

• TEST_ASSERT(i < NUM_SRC_TYPES, "Backing src type ID %d too big", i);
• return &aliases[i];

+}

+size_t get_backing_src_pagesz(uint32_t i) +{

• uint32_t flag = vm_mem_backing_src_alias(i)->flag;
• if (i == VM_MEM_SRC_ANONYMOUS)

• return getpagesize();
  

• if (i == VM_MEM_SRC_ANONYMOUS_THP)

• return get_trans_hugepagesz();
  

• if (i == VM_MEM_SRC_ANONYMOUS_HUGETLB)

• return get_def_hugetlb_pagesz();
  

• return MAP_HUGE_PAGE_SIZE(flag);

+}

• void backing_src_help(void) { int i;

printf("Available backing src types:\n");

• for (i = 0; i < ARRAY_SIZE(backing_src_aliases); i++)

• printf("\t%s\n", backing_src_aliases[i].name);
  

• for (i = 0; i < NUM_SRC_TYPES; i++)
  

• 	printf("\t%s\n", vm_mem_backing_src_alias(i)->name);
  

  }

enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name) { int i;

• for (i = 0; i < ARRAY_SIZE(backing_src_aliases); i++)

• if (!strcmp(type_name, backing_src_aliases[i].name))
  

• 	return backing_src_aliases[i].type;
  

• for (i = 0; i < NUM_SRC_TYPES; i++)

• if (!strcmp(type_name, vm_mem_backing_src_alias(i)->name))
  

• 	return i;
  

This requires vm_mem_backing_src_alias.aliases[] to be in the same order as vm_mem_backing_src_type, so we should do the designated array initialization like in vm_guest_mode_string().

That's right!

Thanks, Yanan

Thanks, drew

...

backing_src_help(); TEST_FAIL("Unknown backing src type: %s", type_name); -- 2.23.0

.

On Tue, Mar 02, 2021 at 08:57:51PM +0800, Yanan Wang wrote:

This test serves as a performance tester and a bug reproducer for kvm page table code (GPA->HPA mappings), so it gives guidance for people trying to make some improvement for kvm.

The function guest_code() can cover the conditions where a single vcpu or multiple vcpus access guest pages within the same memory region, in three VM stages(before dirty logging, during dirty logging, after dirty logging). Besides, the backing src memory type(ANONYMOUS/THP/HUGETLB) of the tested memory region can be specified by users, which means normal page mappings or block mappings can be chosen by users to be created in the test.

If ANONYMOUS memory is specified, kvm will create normal page mappings for the tested memory region before dirty logging, and update attributes of the page mappings from RO to RW during dirty logging. If THP/HUGETLB memory is specified, kvm will create block mappings for the tested memory region before dirty logging, and split the blcok mappings into normal page mappings during dirty logging, and coalesce the page mappings back into block mappings after dirty logging is stopped.

So in summary, as a performance tester, this test can present the performance of kvm creating/updating normal page mappings, or the performance of kvm creating/splitting/recovering block mappings, through execution time.

When we need to coalesce the page mappings back to block mappings after dirty logging is stopped, we have to firstly invalidate *all* the TLB entries for the page mappings right before installation of the block entry, because a TLB conflict abort error could occur if we can't invalidate the TLB entries fully. We have hit this TLB conflict twice on aarch64 software implementation and fixed it. As this test can imulate process from dirty logging enabled to dirty logging stopped of a VM with block mappings, so it can also reproduce this TLB conflict abort due to inadequate TLB invalidation when coalescing tables.

Signed-off-by: Yanan Wang wangyanan55@huawei.com Reviewed-by: Ben Gardon bgardon@google.com

---

tools/testing/selftests/kvm/Makefile | 3 + .../selftests/kvm/kvm_page_table_test.c | 476 ++++++++++++++++++ 2 files changed, 479 insertions(+) create mode 100644 tools/testing/selftests/kvm/kvm_page_table_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index a6d61f451f88..bac81924166d 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -67,6 +67,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/xen_vmcall_test TEST_GEN_PROGS_x86_64 += demand_paging_test TEST_GEN_PROGS_x86_64 += dirty_log_test TEST_GEN_PROGS_x86_64 += dirty_log_perf_test +TEST_GEN_PROGS_x86_64 += kvm_page_table_test TEST_GEN_PROGS_x86_64 += hardware_disable_test TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus TEST_GEN_PROGS_x86_64 += memslot_modification_stress_test @@ -78,6 +79,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list-sve TEST_GEN_PROGS_aarch64 += demand_paging_test TEST_GEN_PROGS_aarch64 += dirty_log_test TEST_GEN_PROGS_aarch64 += dirty_log_perf_test +TEST_GEN_PROGS_aarch64 += kvm_page_table_test TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus TEST_GEN_PROGS_aarch64 += set_memory_region_test TEST_GEN_PROGS_aarch64 += steal_time @@ -87,6 +89,7 @@ TEST_GEN_PROGS_s390x += s390x/resets 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_page_table_test TEST_GEN_PROGS_s390x += kvm_create_max_vcpus TEST_GEN_PROGS_s390x += set_memory_region_test

Please add these three lines in alphabetic order. Also we're missing the .gitignore entry.

diff --git a/tools/testing/selftests/kvm/kvm_page_table_test.c b/tools/testing/selftests/kvm/kvm_page_table_test.c new file mode 100644 index 000000000000..032b49d1483b --- /dev/null +++ b/tools/testing/selftests/kvm/kvm_page_table_test.c @@ -0,0 +1,476 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • KVM page table test
• • Copyright (C) 2021, Huawei, Inc.
• • Make sure that THP has been enabled or enough HUGETLB pages with specific
• • page size have been pre-allocated on your system, if you are planning to
• • use hugepages to back the guest memory for testing.
• */

+#define _GNU_SOURCE /* for program_invocation_name */

+#include <stdio.h> +#include <stdlib.h> +#include <time.h> +#include <pthread.h>

+#include "test_util.h" +#include "kvm_util.h" +#include "processor.h" +#include "guest_modes.h"

+#define TEST_MEM_SLOT_INDEX 1

+/* Default size(1GB) of the memory for testing */ +#define DEFAULT_TEST_MEM_SIZE (1 << 30)

+/* Default guest test virtual memory offset */ +#define DEFAULT_GUEST_TEST_MEM 0xc0000000

+/* Number of guest memory accessing types(read/write) */ +#define NUM_ACCESS_TYPES 2

This define doesn't really seem necessary.

+/* Different guest memory accessing stages */ +enum test_stage {

• KVM_BEFORE_MAPPINGS,
• KVM_CREATE_MAPPINGS,
• KVM_UPDATE_MAPPINGS,
• KVM_ADJUST_MAPPINGS,
• NUM_TEST_STAGES,

+};

+static const char * const test_stage_string[] = {

• "KVM_BEFORE_MAPPINGS",
• "KVM_CREATE_MAPPINGS",
• "KVM_UPDATE_MAPPINGS",
• "KVM_ADJUST_MAPPINGS",

+};

+struct perf_test_vcpu_args {

• int vcpu_id;
• bool vcpu_write;

+};

+struct perf_test_args {

• struct kvm_vm *vm;
• uint64_t guest_test_virt_mem;
• uint64_t host_page_size;
• uint64_t host_num_pages;
• uint64_t large_page_size;
• uint64_t large_num_pages;
• uint64_t host_pages_per_lpage;
• enum vm_mem_backing_src_type src_type;
• struct perf_test_vcpu_args vcpu_args[KVM_MAX_VCPUS];

+};

+/*

• • Guest variables. Use addr_gva2hva() if these variables need
• • to be changed in host.
• */

+static enum test_stage guest_test_stage;

+/* Host variables */ +static uint32_t nr_vcpus = 1; +static struct perf_test_args perf_test_args; +static enum test_stage *current_stage; +static enum test_stage vcpu_last_completed_stage[KVM_MAX_VCPUS]; +static bool host_quit;

+/*

• • Guest physical memory offset of the testing memory slot.
• • This will be set to the topmost valid physical address minus
• • the test memory size.
• */

+static uint64_t guest_test_phys_mem;

+/*

• • Guest virtual memory offset of the testing memory slot.
• • Must not conflict with identity mapped test code.
• */

+static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;

+static void guest_code(int vcpu_id) +{

• struct perf_test_vcpu_args *vcpu_args = &perf_test_args.vcpu_args[vcpu_id];
• enum vm_mem_backing_src_type src_type = perf_test_args.src_type;
• uint64_t host_page_size = perf_test_args.host_page_size;
• uint64_t host_num_pages = perf_test_args.host_num_pages;
• uint64_t large_page_size = perf_test_args.large_page_size;
• uint64_t large_num_pages = perf_test_args.large_num_pages;
• uint64_t host_pages_per_lpage = perf_test_args.host_pages_per_lpage;

Why not just create a short alias for perf_test_args, e.g. p, in order to access these more tersely?

• uint64_t half = host_pages_per_lpage / 2;
• bool vcpu_write;
• enum test_stage stage;
• uint64_t addr;
• int i, j;
• /* Make sure vCPU args data structure is not corrupt */
• GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id);
• vcpu_write = vcpu_args->vcpu_write;
• while (true) {

• stage = READ_ONCE(guest_test_stage);
  

• addr = perf_test_args.guest_test_virt_mem;
  

• switch (stage) {
  

• /*
  

•  * Before dirty logging, vCPUs concurrently access the first
  

•  * 8 bytes of each page (host page/large page) within the same
  

•  * memory region with different accessing types (read/write).
  

•  * Then KVM will create normal page mappings or huge block
  

•  * mappings for them.
  

•  */
  

• case KVM_CREATE_MAPPINGS:
  

• 	for (i = 0; i < large_num_pages; i++) {
  

• 		if (vcpu_write)
  

• 			*(uint64_t *)addr = 0x0123456789ABCDEF;
  

• 		else
  

• 			READ_ONCE(*(uint64_t *)addr);
  

• 		addr += large_page_size;
  

• 	}
  

• 	break;
  

• /*
  

•  * During dirty logging, KVM will only update attributes of the
  

•  * normal page mappings from RO to RW if memory backing src type
  

•  * is anonymous. In other cases, KVM will split the huge block
  

•  * mappings into normal page mappings if memory backing src type
  

•  * is THP or HUGETLB.
  

•  */
  

• case KVM_UPDATE_MAPPINGS:
  

• 	if (src_type == VM_MEM_SRC_ANONYMOUS) {
  

• 		for (i = 0; i < host_num_pages; i++) {
  

• 			*(uint64_t *)addr = 0x0123456789ABCDEF;
  

• 			addr += host_page_size;
  

• 		}
  

• 		break;
  

• 	}
  

• 	for (i = 0; i < large_num_pages; i++) {
  

• 		/*
  

• 		 * Write to the first host page in each large
  

• 		 * page region, and triger break of large pages.
  

• 		 */
  

• 		*(uint64_t *)addr = 0x0123456789ABCDEF;
  

• 		/*
  

• 		 * Access the middle host pages in each large
  

• 		 * page region. Since dirty logging is enabled,
  

• 		 * this will create new mappings at the smallest
  

• 		 * granularity.
  

• 		 */
  

• 		addr += host_page_size * half;
  

• 		for (j = half; j < host_pages_per_lpage; j++) {
  

• 			READ_ONCE(*(uint64_t *)addr);
  

• 			addr += host_page_size;
  

• 		}
  

• 	}
  

• 	break;
  

• /*
  

•  * After dirty logging is stopped, vCPUs concurrently read
  

•  * from every single host page. Then KVM will coalesce the
  

•  * split page mappings back to block mappings. And a TLB
  

•  * conflict abort could occur here if TLB entries of the
  

•  * page mappings are not fully invalidated.
  

•  */
  

• case KVM_ADJUST_MAPPINGS:
  

• 	for (i = 0; i < host_num_pages; i++) {
  

• 		READ_ONCE(*(uint64_t *)addr);
  

• 		addr += host_page_size;
  

• 	}
  

• 	break;
  

• default:
  

• 	break;
  

• }
  

• GUEST_SYNC(1);
  

• }

+}

+static void *vcpu_worker(void *data) +{

• int ret;
• struct perf_test_vcpu_args *vcpu_args = data;
• struct kvm_vm *vm = perf_test_args.vm;
• int vcpu_id = vcpu_args->vcpu_id;
• struct kvm_run *run;
• struct timespec start;
• struct timespec ts_diff;
• enum test_stage stage;
• vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
• run = vcpu_state(vm, vcpu_id);
• while (!READ_ONCE(host_quit)) {

• clock_gettime(CLOCK_MONOTONIC_RAW, &start);
  

• ret = _vcpu_run(vm, vcpu_id);
  

• ts_diff = timespec_elapsed(start);
  

• TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
  

• TEST_ASSERT(get_ucall(vm, vcpu_id, NULL) == UCALL_SYNC,
  

• 	    "Invalid guest sync status: exit_reason=%s\n",
  

• 	    exit_reason_str(run->exit_reason));
  

• pr_debug("Got sync event from vCPU %d\n", vcpu_id);
  

• stage = READ_ONCE(*current_stage);
  

• vcpu_last_completed_stage[vcpu_id] = stage;
  

• pr_debug("vCPU %d has completed stage %s\n"
  

• 	 "execution time is: %ld.%.9lds\n\n",
  

• 	 vcpu_id, test_stage_string[stage],
  

• 	 ts_diff.tv_sec, ts_diff.tv_nsec);
  

• while (stage == READ_ONCE(*current_stage) &&
  

•        !READ_ONCE(host_quit)) {}
  

Why busy wait instead of using some synchronization? E.g. sem_wait?

• }
• return NULL;

+}

+struct test_params {

• uint64_t phys_offset;
• uint64_t test_mem_size;
• enum vm_mem_backing_src_type src_type;

+};

+static struct kvm_vm *pre_init_before_test(enum vm_guest_mode mode, void *arg) +{

• struct test_params *p = arg;
• struct perf_test_vcpu_args *vcpu_args;
• enum vm_mem_backing_src_type src_type = p->src_type;
• uint64_t large_page_size = get_backing_src_pagesz(src_type);
• uint64_t test_mem_size = p->test_mem_size, guest_num_pages;
• uint64_t guest_page_size = vm_guest_mode_params[mode].page_size;
• uint64_t host_page_size = getpagesize();
• uint64_t alignment;
• void *host_test_mem;
• struct kvm_vm *vm;
• int vcpu_id;
• /* Align up the test memory size */
• alignment = max(large_page_size, guest_page_size);
• test_mem_size = (test_mem_size + alignment - 1) & ~(alignment - 1);
• /* Create a VM with enough guest pages */
• guest_num_pages = test_mem_size / guest_page_size;
• vm = vm_create_with_vcpus(mode, nr_vcpus,

• 		  guest_num_pages, 0, guest_code, NULL);
  

• /* Align down GPA of the testing memslot */
• if (!p->phys_offset)

• guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *
  

• 		       guest_page_size;
  

• else

• guest_test_phys_mem = p->phys_offset;
  

+#ifdef __s390x__

• alignment = max(0x100000, alignment);

+#endif

• guest_test_phys_mem &= ~(alignment - 1);
• /* Set up the shared data structure perf_test_args */
• perf_test_args.vm = vm;
• perf_test_args.guest_test_virt_mem = guest_test_virt_mem;
• perf_test_args.host_page_size = host_page_size;
• perf_test_args.host_num_pages = test_mem_size / host_page_size;
• perf_test_args.large_page_size = large_page_size;
• perf_test_args.large_num_pages = test_mem_size / large_page_size;
• perf_test_args.host_pages_per_lpage = large_page_size / host_page_size;
• perf_test_args.src_type = src_type;
• for (vcpu_id = 0; vcpu_id < KVM_MAX_VCPUS; vcpu_id++) {

• vcpu_args = &perf_test_args.vcpu_args[vcpu_id];
  

• vcpu_args->vcpu_id = vcpu_id;
  

• vcpu_args->vcpu_write = !(vcpu_id % NUM_ACCESS_TYPES);
  

Why the '!'? Is this to ensure vcpu_id=0 is a writer? If so, why?

• vcpu_last_completed_stage[vcpu_id] = NUM_TEST_STAGES;
  

• }
• /* Add an extra memory slot with specified backing src type */
• vm_userspace_mem_region_add(vm, src_type, guest_test_phys_mem,

• 		    TEST_MEM_SLOT_INDEX, guest_num_pages, 0);
  

• /* Do mapping(GVA->GPA) for the testing memory slot */
• virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages, 0);
• /* Cache the HVA pointer of the region */
• host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
• /* Export shared structure perf_test_args to guest */
• ucall_init(vm, NULL);
• sync_global_to_guest(vm, perf_test_args);
• current_stage = addr_gva2hva(vm, (vm_vaddr_t)(&guest_test_stage));
• *current_stage = NUM_TEST_STAGES;
• pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
• pr_info("Testing memory backing src type: %s\n",

• vm_mem_backing_src_alias(src_type)->name);
  

• pr_info("Testing memory backing src granularity: 0x%lx\n",

• large_page_size);
  

• pr_info("Testing memory size(aligned): 0x%lx\n", test_mem_size);
• pr_info("Guest physical test memory offset: 0x%lx\n",

• guest_test_phys_mem);
  

• pr_info("Host virtual test memory offset: 0x%lx\n",

• (uint64_t)host_test_mem);
  

• pr_info("Number of testing vCPUs: %d\n", nr_vcpus);
• return vm;

+}

+static void run_test(enum vm_guest_mode mode, void *arg) +{

• pthread_t *vcpu_threads;
• struct kvm_vm *vm;
• int vcpu_id;
• enum test_stage stage;
• struct timespec start;
• struct timespec ts_diff;
• /* Create VM with vCPUs and make some pre-initialization */
• vm = pre_init_before_test(mode, arg);
• vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
• TEST_ASSERT(vcpu_threads, "Memory allocation failed");
• host_quit = false;
• stage = KVM_BEFORE_MAPPINGS;
• *current_stage = stage;
• for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {

• pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
  

• 	       &perf_test_args.vcpu_args[vcpu_id]);
  

• }
• for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {

• while (READ_ONCE(vcpu_last_completed_stage[vcpu_id]) != stage)
  

• 	pr_debug("Waiting for vCPU %d to complete stage %s\n",
  

• 		 vcpu_id, test_stage_string[stage]);
  

I'd do a timed wait on some synchronization and then assert that it doesn't time out. At least the pr_debug() in the loop doesn't look like a good idea.

• }
• pr_info("Started all vCPUs successfully\n");
• /* Test the stage of KVM creating mappings */
• clock_gettime(CLOCK_MONOTONIC_RAW, &start);
• stage = KVM_CREATE_MAPPINGS;
• *current_stage = stage;
• for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {

• while (READ_ONCE(vcpu_last_completed_stage[vcpu_id]) != stage)
  

• 	pr_debug("Waiting for vCPU %d to complete stage %s\n",
  

• 		 vcpu_id, test_stage_string[stage]);
  

• }
• ts_diff = timespec_elapsed(start);
• pr_info("KVM_CREATE_MAPPINGS: total execution time: %ld.%.9lds\n\n",

• ts_diff.tv_sec, ts_diff.tv_nsec);
  

Here the busy loop makes some sense for the time measuring. Alternatively we could still use sem_wait, but have the first vcpu to start record the start time and the last vcpu to finish record the end time. It might be nice to be able to see each individual vcpu's time too.

• /* Test the stage of KVM updating mappings */
• vm_mem_region_set_flags(vm, TEST_MEM_SLOT_INDEX,

• 		KVM_MEM_LOG_DIRTY_PAGES);
  

• clock_gettime(CLOCK_MONOTONIC_RAW, &start);
• stage = KVM_UPDATE_MAPPINGS;
• *current_stage = stage;
• for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {

• while (READ_ONCE(vcpu_last_completed_stage[vcpu_id]) != stage)
  

• 	pr_debug("Waiting for vCPU %d to complete stage %s\n",
  

• 		 vcpu_id, test_stage_string[stage]);
  

• }
• ts_diff = timespec_elapsed(start);
• pr_info("KVM_UPDATE_MAPPINGS: total execution time: %ld.%.9lds\n\n",

• ts_diff.tv_sec, ts_diff.tv_nsec);
  

• /* Test the stage of KVM adjusting mappings */
• vm_mem_region_set_flags(vm, TEST_MEM_SLOT_INDEX, 0);
• clock_gettime(CLOCK_MONOTONIC_RAW, &start);
• stage = KVM_ADJUST_MAPPINGS;
• *current_stage = stage;
• for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {

• while (READ_ONCE(vcpu_last_completed_stage[vcpu_id]) != stage)
  

• 	pr_debug("Waiting for vCPU %d to complete stage %s\n",
  

• 		 vcpu_id, test_stage_string[stage]);
  

• }
• ts_diff = timespec_elapsed(start);
• pr_info("KVM_ADJUST_MAPPINGS: total execution time: %ld.%.9lds\n\n",

• ts_diff.tv_sec, ts_diff.tv_nsec);
  

Same comments for the last two loops as above about pr_debug and possibly using some synchronization. At least these loops, which are all the same, could be factored out into a function.

• /* Tell the vcpu thread to quit */
• host_quit = true;
• for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)

• pthread_join(vcpu_threads[vcpu_id], NULL);
  

• free(vcpu_threads);
• ucall_uninit(vm);
• kvm_vm_free(vm);

+}

+static void help(char *name) +{

• puts("");
• printf("usage: %s [-h] [-p offset] [-m mode] "

•       "[-b mem size] [-v vcpus] [-s mem type]\n", name);
  

Please hyphenate the parameter names: mem-size, mem-type

• puts("");
• printf(" -p: specify guest physical test memory offset\n"

•       "     Warning: a low offset can conflict with the loaded test code.\n");
  

• guest_modes_help();
• printf(" -b: specify size of the memory region for testing. e.g. 10M or 3G.\n"

•       "     (default: 1G)\n");
  

• printf(" -v: specify the number of vCPUs to run\n"

•       "     (default: 1)\n");
  

• printf(" -s: specify the type of memory that should be used to\n"

•       "     back the guest data region.\n"
  

•       "     (default: anonymous)\n\n");
  

• backing_src_help();
• puts("");
• exit(0);

+}

+int main(int argc, char *argv[]) +{

• int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
• struct test_params p = {

• .test_mem_size = DEFAULT_TEST_MEM_SIZE,
  

• .src_type = VM_MEM_SRC_ANONYMOUS,
  

• };
• int opt;
• guest_modes_append_default();
• while ((opt = getopt(argc, argv, "hp:m:b:v:s:")) != -1) {

• switch (opt) {
  

• case 'p':
  

• 	p.phys_offset = strtoull(optarg, NULL, 0);
  

• 	break;
  

• case 'm':
  

• 	guest_modes_cmdline(optarg);
  

• 	break;
  

• case 'b':
  

• 	p.test_mem_size = parse_size(optarg);
  

• 	break;
  

• case 'v':
  

• 	nr_vcpus = atoi(optarg);
  

• 	TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus,
  

• 		    "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
  

• 	break;
  

• case 's':
  

• 	p.src_type = parse_backing_src_type(optarg);
  

• 	break;
  

• case 'h':
  

• default:
  

• 	help(argv[0]);
  

• 	break;
  

• }
  

• }
• for_each_guest_mode(run_test, &p);
• return 0;

+}

2.23.0

Thanks, drew