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[23.128.96.18]) by mx.google.com with ESMTP id s21si4535273edd.135.2021.02.18.18.11.55; Thu, 18 Feb 2021 18:12:18 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=bT7+ynxI; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229804AbhBSCIu (ORCPT + 99 others); Thu, 18 Feb 2021 21:08:50 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:2737 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229471AbhBSCIs (ORCPT ); Thu, 18 Feb 2021 21:08:48 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Thu, 18 Feb 2021 18:08:07 -0800 Received: from localhost (172.20.145.6) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 19 Feb 2021 02:08:06 +0000 From: Alistair Popple To: , , , CC: , , , , , , , , , , Alistair Popple Subject: [PATCH v2 2/4] hmm: Selftests for exclusive device memory Date: Fri, 19 Feb 2021 13:07:48 +1100 Message-ID: <20210219020750.16444-3-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210219020750.16444-1-apopple@nvidia.com> References: <20210219020750.16444-1-apopple@nvidia.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1613700487; bh=UOgMin+hr8IvGv0vIpPpaKdghp+MMGxdR4XPVayfQ8E=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=bT7+ynxI02R88DBM4bpvxstp5MfaC50RGerw17lcVytVWuEpQTerVe6Nsm+tZG9RY Z0WU902W3s5DhWssFDXGBug04f0eEi2lI0eI1Q1FCRDP5a2BEu1iiUsQFneMzcOqDe GDuhQWZB8sHoJrY7MbI/4AGQqv4fY6i4co9zoQojGhTZeH0SZYT29XLjmxu3JJi4zE /XiuknmQi74O6ZCiaRoOWkjBiKsreWJv6ybHoh6f6ZwamZKpY2OoT7aFztTYDMkbOa zSIRcmGsUaL5w7o6raobC5TE1HHdpRQr1ojI1h3YoBr78ot/Q9kuFEakRirXjm0xb5 Hm36JvWrBi2iA== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adds some selftests for exclusive device memory. Signed-off-by: Alistair Popple --- lib/test_hmm.c | 124 ++++++++++++++ lib/test_hmm_uapi.h | 2 + tools/testing/selftests/vm/hmm-tests.c | 219 +++++++++++++++++++++++++ 3 files changed, 345 insertions(+) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 80a78877bd93..d517d9d4c5aa 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 migr= ate_vma *args, } } =20 +static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long sta= rt, + 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); pfn= ++, 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 mig= rate_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 + (64 << PAGE_SHIFT)) + next =3D end; + else + next =3D addr + (64 << PAGE_SHIFT); + + ret =3D hmm_exclusive_range(mm, addr, next, pages); + 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_cm= d) =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/selftes= ts/vm/hmm-tests.c index 5d1ac691b9f4..5d3c5db9ed3a 100644 --- a/tools/testing/selftests/vm/hmm-tests.c +++ b/tools/testing/selftests/vm/hmm-tests.c @@ -1485,4 +1485,223 @@ 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, np= ages); + ASSERT_EQ(ret, 0); + + hmm_buffer_free(buffer); +} + +TEST_F(hmm, exclusive_shared) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + int *ptr; + int ret, i; + + 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_SHARED | 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, np= ages); + ASSERT_FALSE(ret); + + /* Map memory exclusively for device access again to check process tear d= own */ + ret =3D hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + hmm_buffer_free(buffer); +} + +/* + * Same as above but for shared anonymous memory. + */ +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