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Signed-off-by: Alistair Popple Acked-by: Jason Gunthorpe Tested-by: Ralph Campbell Reviewed-by: Ralph Campbell --- lib/test_hmm.c | 124 +++++++++++++++++++ lib/test_hmm_uapi.h | 2 + tools/testing/selftests/vm/hmm-tests.c | 158 +++++++++++++++++++++++++ 3 files changed, 284 insertions(+) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 5c9f5a020c1d..305a9d9e2b4c 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -25,6 +25,7 @@ #include #include #include +#include =20 #include "test_hmm_uapi.h" =20 @@ -46,6 +47,7 @@ struct dmirror_bounce { unsigned long cpages; }; =20 +#define DPT_XA_TAG_ATOMIC 1UL #define DPT_XA_TAG_WRITE 3UL =20 /* @@ -619,6 +621,54 @@ static void dmirror_migrate_alloc_and_copy(struct mi= grate_vma *args, } } =20 +static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long s= tart, + unsigned long end) +{ + unsigned long pfn; + + for (pfn =3D start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { + void *entry; + struct page *page; + + entry =3D xa_load(&dmirror->pt, pfn); + page =3D xa_untag_pointer(entry); + if (xa_pointer_tag(entry) =3D=3D DPT_XA_TAG_ATOMIC) + return -EPERM; + } + + return 0; +} + +static int dmirror_atomic_map(unsigned long start, unsigned long end, + struct page **pages, struct dmirror *dmirror) +{ + unsigned long pfn, mapped =3D 0; + int i; + + /* Map the migrated pages into the device's page tables. */ + mutex_lock(&dmirror->mutex); + + for (i =3D 0, pfn =3D start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); p= fn++, i++) { + void *entry; + + if (!pages[i]) + continue; + + entry =3D pages[i]; + entry =3D xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC); + entry =3D xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); + if (xa_is_err(entry)) { + mutex_unlock(&dmirror->mutex); + return xa_err(entry); + } + + mapped++; + } + + mutex_unlock(&dmirror->mutex); + return mapped; +} + static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, struct dmirror *dmirror) { @@ -661,6 +711,71 @@ static int dmirror_migrate_finalize_and_map(struct m= igrate_vma *args, return 0; } =20 +static int dmirror_exclusive(struct dmirror *dmirror, + struct hmm_dmirror_cmd *cmd) +{ + unsigned long start, end, addr; + unsigned long size =3D cmd->npages << PAGE_SHIFT; + struct mm_struct *mm =3D dmirror->notifier.mm; + struct page *pages[64]; + struct dmirror_bounce bounce; + unsigned long next; + int ret; + + start =3D cmd->addr; + end =3D start + size; + if (end < start) + return -EINVAL; + + /* Since the mm is for the mirrored process, get a reference first. */ + if (!mmget_not_zero(mm)) + return -EINVAL; + + mmap_read_lock(mm); + for (addr =3D start; addr < end; addr =3D next) { + int i, mapped; + + if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT)) + next =3D end; + else + next =3D addr + (ARRAY_SIZE(pages) << PAGE_SHIFT); + + ret =3D make_device_exclusive_range(mm, addr, next, pages, NULL); + mapped =3D dmirror_atomic_map(addr, next, pages, dmirror); + for (i =3D 0; i < ret; i++) { + if (pages[i]) { + unlock_page(pages[i]); + put_page(pages[i]); + } + } + + if (addr + (mapped << PAGE_SHIFT) < next) { + mmap_read_unlock(mm); + mmput(mm); + return -EBUSY; + } + } + mmap_read_unlock(mm); + mmput(mm); + + /* Return the migrated data for verification. */ + ret =3D dmirror_bounce_init(&bounce, start, size); + if (ret) + return ret; + mutex_lock(&dmirror->mutex); + ret =3D dmirror_do_read(dmirror, start, end, &bounce); + mutex_unlock(&dmirror->mutex); + if (ret =3D=3D 0) { + if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, + bounce.size)) + ret =3D -EFAULT; + } + + cmd->cpages =3D bounce.cpages; + dmirror_bounce_fini(&bounce); + return ret; +} + static int dmirror_migrate(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) { @@ -949,6 +1064,15 @@ static long dmirror_fops_unlocked_ioctl(struct file= *filp, ret =3D dmirror_migrate(dmirror, &cmd); break; =20 + case HMM_DMIRROR_EXCLUSIVE: + ret =3D dmirror_exclusive(dmirror, &cmd); + break; + + case HMM_DMIRROR_CHECK_EXCLUSIVE: + ret =3D dmirror_check_atomic(dmirror, cmd.addr, + cmd.addr + (cmd.npages << PAGE_SHIFT)); + break; + case HMM_DMIRROR_SNAPSHOT: ret =3D dmirror_snapshot(dmirror, &cmd); break; diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h index 670b4ef2a5b6..f14dea5dcd06 100644 --- a/lib/test_hmm_uapi.h +++ b/lib/test_hmm_uapi.h @@ -33,6 +33,8 @@ struct hmm_dmirror_cmd { #define HMM_DMIRROR_WRITE _IOWR('H', 0x01, struct hmm_dmirror_cmd) #define HMM_DMIRROR_MIGRATE _IOWR('H', 0x02, struct hmm_dmirror_cmd) #define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x03, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x04, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_= cmd) =20 /* * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT. diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selft= ests/vm/hmm-tests.c index 5d1ac691b9f4..864f126ffd78 100644 --- a/tools/testing/selftests/vm/hmm-tests.c +++ b/tools/testing/selftests/vm/hmm-tests.c @@ -1485,4 +1485,162 @@ TEST_F(hmm2, double_map) hmm_buffer_free(buffer); } =20 +/* + * Basic check of exclusive faulting. + */ +TEST_F(hmm, exclusive) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + unsigned long i; + int *ptr; + int ret; + + npages =3D ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size =3D npages << self->page_shift; + + buffer =3D malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd =3D -1; + buffer->size =3D size; + buffer->mirror =3D malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr =3D mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] =3D i; + + /* Map memory exclusively for device access. */ + ret =3D hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages= ); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i =3D 0, ptr =3D buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + /* Fault pages back to system memory and check them. */ + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i]++, i); + + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i+1); + + /* Check atomic access revoked */ + ret =3D hmm_dmirror_cmd(self->fd, HMM_DMIRROR_CHECK_EXCLUSIVE, buffer, = npages); + ASSERT_EQ(ret, 0); + + hmm_buffer_free(buffer); +} + +TEST_F(hmm, exclusive_mprotect) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + unsigned long i; + int *ptr; + int ret; + + npages =3D ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size =3D npages << self->page_shift; + + buffer =3D malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd =3D -1; + buffer->size =3D size; + buffer->mirror =3D malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr =3D mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] =3D i; + + /* Map memory exclusively for device access. */ + ret =3D hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages= ); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i =3D 0, ptr =3D buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + ret =3D mprotect(buffer->ptr, size, PROT_READ); + ASSERT_EQ(ret, 0); + + /* Simulate a device writing system memory. */ + ret =3D hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages); + ASSERT_EQ(ret, -EPERM); + + hmm_buffer_free(buffer); +} + +/* + * Check copy-on-write works. + */ +TEST_F(hmm, exclusive_cow) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + unsigned long i; + int *ptr; + int ret; + + npages =3D ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size =3D npages << self->page_shift; + + buffer =3D malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd =3D -1; + buffer->size =3D size; + buffer->mirror =3D malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr =3D mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] =3D i; + + /* Map memory exclusively for device access. */ + ret =3D hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages= ); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + fork(); + + /* Fault pages back to system memory and check them. */ + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i]++, i); + + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i+1); + + hmm_buffer_free(buffer); +} + TEST_HARNESS_MAIN --=20 2.20.1