From patchwork Sat Dec 16 00:21:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elliot Berman X-Patchwork-Id: 754882 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91DC51798D; Sat, 16 Dec 2023 00:21:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="NL3t/F79" Received: from pps.filterd (m0279862.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 3BFNe7sr027607; Sat, 16 Dec 2023 00:21:14 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= from:date:subject:mime-version:content-type :content-transfer-encoding:message-id:references:in-reply-to:to :cc; s=qcppdkim1; bh=Pj31zjbqZFPkFusPu9Yv3U2hJdd1v8pz9tCQL82AZ/k =; b=NL3t/F79t8LehsgKLsTNSLpjudW5vUXn++EttPLX9+4bXu3R1a7c9mjMUzm V8HrkxuE8vLwtL3YzTzdg7nMfh95F9i4RNHrP7aOv5b+fcMUPHgZV1Hk0W6MBBPF cIaPO9m8o0BifJmBpIOyUqpULedur6Rr4Yn6NschRptX2O0ny3DuC6WtWaakcCTr DtpdEgrZ/vCm83ulcauOLfhl/dxKLRb/NroCDHLPNmcwYo1KJ+c/ZODBhmV8RsVc 0964dLUoGfVbp+s3d8Xuk1SbDKVVIAb1xRCdk5cvT2dRj9NswS7dSuKH4nXggLQ1 WUYiOdlRdQ+kjAaY6fg68jskIvQ== Received: from nasanppmta05.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3v0w198hpj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 16 Dec 2023 00:21:13 +0000 (GMT) Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA05.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 3BG0LDrn006365 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 16 Dec 2023 00:21:13 GMT Received: from [169.254.0.1] (10.49.16.6) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Fri, 15 Dec 2023 16:21:12 -0800 From: Elliot Berman Date: Fri, 15 Dec 2023 16:21:01 -0800 Subject: [PATCH RFC v15 20/30] virt: gunyah: Implement guestmemfd Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <20231215-gunyah-v15-20-192a5d872a30@quicinc.com> References: <20231215-gunyah-v15-0-192a5d872a30@quicinc.com> In-Reply-To: <20231215-gunyah-v15-0-192a5d872a30@quicinc.com> To: Alex Elder , Srinivas Kandagatla , Murali Nalajal , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Philip Derrin , Prakruthi Deepak Heragu , Jonathan Corbet , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Konrad Dybcio , Bjorn Andersson , Dmitry Baryshkov , "Fuad Tabba" , Sean Christopherson CC: , , , , , Elliot Berman X-Mailer: b4 0.13-dev X-ClientProxiedBy: nalasex01a.na.qualcomm.com (10.47.209.196) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: e6UnKX19G6FgW5fsT85__qq9ITvodVUF X-Proofpoint-ORIG-GUID: e6UnKX19G6FgW5fsT85__qq9ITvodVUF X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-09_01,2023-12-07_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 mlxlogscore=999 suspectscore=0 mlxscore=0 impostorscore=0 lowpriorityscore=0 spamscore=0 adultscore=0 phishscore=0 clxscore=1015 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2311290000 definitions=main-2312160001 Memory provided to Gunyah virtual machines are provided by a Gunyah guestmemfd. Because memory provided to virtual machines may be unmapped at stage-2 from the host (i.e. in the hypervisor's page tables for the host), special care needs to be taken to ensure that the kernel doesn't have a page mapped when it is lent to the guest. Without this tracking, a kernel panic could be induced by userspace tricking the kernel into accessing guest-private memory. Introduce the basic guestmemfd ops and ioctl. Userspace should be able to access the memory unless it is provided to the guest virtual machine: this is necessary to allow userspace to preload binaries such as the kernel Image prior to running the VM. Subsequent commits will wire up providing the memory to the guest. Signed-off-by: Elliot Berman --- drivers/virt/gunyah/Makefile | 2 +- drivers/virt/gunyah/guest_memfd.c | 269 ++++++++++++++++++++++++++++++++++++++ drivers/virt/gunyah/vm_mgr.c | 9 ++ drivers/virt/gunyah/vm_mgr.h | 2 + include/uapi/linux/gunyah.h | 19 +++ 5 files changed, 300 insertions(+), 1 deletion(-) diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile index ffcde0e0ccfa..9d514b2baa3a 100644 --- a/drivers/virt/gunyah/Makefile +++ b/drivers/virt/gunyah/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 -gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mem.o +gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mem.o guest_memfd.o obj-$(CONFIG_GUNYAH) += gunyah.o gunyah_rsc_mgr.o gunyah_vcpu.o obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o diff --git a/drivers/virt/gunyah/guest_memfd.c b/drivers/virt/gunyah/guest_memfd.c new file mode 100644 index 000000000000..709aae9a1f44 --- /dev/null +++ b/drivers/virt/gunyah/guest_memfd.c @@ -0,0 +1,269 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#define pr_fmt(fmt) "gunyah_guest_mem: " fmt + +#include +#include +#include +#include +#include +#include + +#include + +static struct folio *gunyah_gmem_get_huge_folio(struct inode *inode, + pgoff_t index) +{ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + unsigned long huge_index = round_down(index, HPAGE_PMD_NR); + unsigned long flags = (unsigned long)inode->i_private; + struct address_space *mapping = inode->i_mapping; + gfp_t gfp = mapping_gfp_mask(mapping); + struct folio *folio; + + if (!(flags & GHMF_ALLOW_HUGEPAGE)) + return NULL; + + if (filemap_range_has_page(mapping, huge_index << PAGE_SHIFT, + (huge_index + HPAGE_PMD_NR - 1) + << PAGE_SHIFT)) + return NULL; + + folio = filemap_alloc_folio(gfp, HPAGE_PMD_ORDER); + if (!folio) + return NULL; + + if (filemap_add_folio(mapping, folio, huge_index, gfp)) { + folio_put(folio); + return NULL; + } + + return folio; +#else + return NULL; +#endif +} + +static struct folio *gunyah_gmem_get_folio(struct inode *inode, pgoff_t index) +{ + struct folio *folio; + + folio = gunyah_gmem_get_huge_folio(inode, index); + if (!folio) { + folio = filemap_grab_folio(inode->i_mapping, index); + if (IS_ERR_OR_NULL(folio)) + return NULL; + } + + /* + * Use the up-to-date flag to track whether or not the memory has been + * zeroed before being handed off to the guest. There is no backing + * storage for the memory, so the folio will remain up-to-date until + * it's removed. + */ + if (!folio_test_uptodate(folio)) { + unsigned long nr_pages = folio_nr_pages(folio); + unsigned long i; + + for (i = 0; i < nr_pages; i++) + clear_highpage(folio_page(folio, i)); + + folio_mark_uptodate(folio); + } + + /* + * Ignore accessed, referenced, and dirty flags. The memory is + * unevictable and there is no storage to write back to. + */ + return folio; +} + +static vm_fault_t gunyah_gmem_host_fault(struct vm_fault *vmf) +{ + struct folio *folio; + + folio = gunyah_gmem_get_folio(file_inode(vmf->vma->vm_file), + vmf->pgoff); + if (!folio || folio_test_private(folio)) { + folio_unlock(folio); + folio_put(folio); + return VM_FAULT_SIGBUS; + } + + vmf->page = folio_file_page(folio, vmf->pgoff); + + return VM_FAULT_LOCKED; +} + +static const struct vm_operations_struct gunyah_gmem_vm_ops = { + .fault = gunyah_gmem_host_fault, +}; + +static int gunyah_gmem_mmap(struct file *file, struct vm_area_struct *vma) +{ + file_accessed(file); + vma->vm_ops = &gunyah_gmem_vm_ops; + return 0; +} + +static long gunyah_gmem_punch_hole(struct inode *inode, loff_t offset, + loff_t len) +{ + truncate_inode_pages_range(inode->i_mapping, offset, offset + len - 1); + + return 0; +} + +static long gunyah_gmem_allocate(struct inode *inode, loff_t offset, loff_t len) +{ + struct address_space *mapping = inode->i_mapping; + pgoff_t start, index, end; + int r; + + /* Dedicated guest is immutable by default. */ + if (offset + len > i_size_read(inode)) + return -EINVAL; + + filemap_invalidate_lock_shared(mapping); + + start = offset >> PAGE_SHIFT; + end = (offset + len) >> PAGE_SHIFT; + + r = 0; + for (index = start; index < end;) { + struct folio *folio; + + if (signal_pending(current)) { + r = -EINTR; + break; + } + + folio = gunyah_gmem_get_folio(inode, index); + if (!folio) { + r = -ENOMEM; + break; + } + + index = folio_next_index(folio); + + folio_unlock(folio); + folio_put(folio); + + /* 64-bit only, wrapping the index should be impossible. */ + if (WARN_ON_ONCE(!index)) + break; + + cond_resched(); + } + + filemap_invalidate_unlock_shared(mapping); + + return r; +} + +static long gunyah_gmem_fallocate(struct file *file, int mode, loff_t offset, + loff_t len) +{ + long ret; + + if (!(mode & FALLOC_FL_KEEP_SIZE)) + return -EOPNOTSUPP; + + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | + FALLOC_FL_ZERO_RANGE)) + return -EOPNOTSUPP; + + if (!PAGE_ALIGNED(offset) || !PAGE_ALIGNED(len)) + return -EINVAL; + + if (mode & FALLOC_FL_PUNCH_HOLE) + ret = gunyah_gmem_punch_hole(file_inode(file), offset, len); + else + ret = gunyah_gmem_allocate(file_inode(file), offset, len); + + if (!ret) + file_modified(file); + return ret; +} + +static int gunyah_gmem_release(struct inode *inode, struct file *file) +{ + gunyah_gmem_punch_hole(inode, 0, U64_MAX); + + return 0; +} + +static const struct file_operations gunyah_gmem_fops = { + .owner = THIS_MODULE, + .llseek = generic_file_llseek, + .mmap = gunyah_gmem_mmap, + .open = generic_file_open, + .fallocate = gunyah_gmem_fallocate, + .release = gunyah_gmem_release, +}; + +static const struct address_space_operations gunyah_gmem_aops = { + .dirty_folio = noop_dirty_folio, + .migrate_folio = migrate_folio, + .error_remove_folio = generic_error_remove_folio, +}; + +int gunyah_guest_mem_create(struct gunyah_create_mem_args *args) +{ + const char *anon_name = "[gh-gmem]"; + unsigned long fd_flags = 0; + struct inode *inode; + struct file *file; + int fd, err; + + if (!PAGE_ALIGNED(args->size)) + return -EINVAL; + + if (args->flags & ~(GHMF_CLOEXEC | GHMF_ALLOW_HUGEPAGE)) + return -EINVAL; + + if (args->flags & GHMF_CLOEXEC) + fd_flags |= O_CLOEXEC; + + fd = get_unused_fd_flags(fd_flags); + if (fd < 0) + return fd; + + /* + * Use the so called "secure" variant, which creates a unique inode + * instead of reusing a single inode. Each guest_memfd instance needs + * its own inode to track the size, flags, etc. + */ + file = anon_inode_create_getfile(anon_name, &gunyah_gmem_fops, NULL, + O_RDWR, NULL); + if (IS_ERR(file)) { + err = PTR_ERR(file); + goto err_fd; + } + + file->f_flags |= O_LARGEFILE; + + inode = file->f_inode; + WARN_ON(file->f_mapping != inode->i_mapping); + + inode->i_private = (void *)(unsigned long)args->flags; + inode->i_mapping->a_ops = &gunyah_gmem_aops; + inode->i_mode |= S_IFREG; + inode->i_size = args->size; + mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_set_large_folios(inode->i_mapping); + mapping_set_unmovable(inode->i_mapping); + // mapping_set_release_always(inode->i_mapping); + /* Unmovable mappings are supposed to be marked unevictable as well. */ + WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); + + fd_install(fd, file); + return fd; + +err_fd: + put_unused_fd(fd); + return err; +} diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c index 9e402e6ea7fe..cd978d1ce93f 100644 --- a/drivers/virt/gunyah/vm_mgr.c +++ b/drivers/virt/gunyah/vm_mgr.c @@ -799,6 +799,15 @@ long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd, switch (cmd) { case GUNYAH_CREATE_VM: return gunyah_dev_ioctl_create_vm(rm, arg); + case GUNYAH_CREATE_GUEST_MEM: { + struct gunyah_create_mem_args args; + + if (copy_from_user(&args, (const void __user *)arg, + sizeof(args))) + return -EFAULT; + + return gunyah_guest_mem_create(&args); + } default: return -ENOTTY; } diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h index 348dbeda57ec..d26693d10d22 100644 --- a/drivers/virt/gunyah/vm_mgr.h +++ b/drivers/virt/gunyah/vm_mgr.h @@ -77,4 +77,6 @@ void gunyah_vm_reclaim_memory(struct gunyah_vm *ghvm); int gunyah_vm_mmio_write(struct gunyah_vm *ghvm, u64 addr, u32 len, u64 data); +int gunyah_guest_mem_create(struct gunyah_create_mem_args *args); + #endif diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h index 46f7d3aa61d0..c5f506350364 100644 --- a/include/uapi/linux/gunyah.h +++ b/include/uapi/linux/gunyah.h @@ -20,6 +20,25 @@ */ #define GUNYAH_CREATE_VM _IO(GUNYAH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */ +enum gunyah_mem_flags { + GHMF_CLOEXEC = (1UL << 0), + GHMF_ALLOW_HUGEPAGE = (1UL << 1), +}; + +/** + * struct gunyah_create_mem_args - Description of guest memory to create + * @flags: See GHMF_*. + */ +struct gunyah_create_mem_args { + __u64 flags; + __u64 size; + __u64 reserved[6]; +}; + +#define GUNYAH_CREATE_GUEST_MEM \ + _IOW(GUNYAH_IOCTL_TYPE, 0x8, \ + struct gunyah_create_mem_args) /* Returns a Gunyah memory fd */ + /* * ioctls for gunyah-vm fds (returned by GUNYAH_CREATE_VM) */