From patchwork Tue Jan 9 19:37:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elliot Berman X-Patchwork-Id: 761165 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (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 CFDF940C0B; Tue, 9 Jan 2024 19:38:25 +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="Lo5n72Mz" Received: from pps.filterd (m0279871.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 409JEnrB008597; Tue, 9 Jan 2024 19:38:04 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=miMCDfTEk99kjZA/iq3tKBkY47MzQ24QITHB/sPM65M =; b=Lo5n72MzcMcHMEz31QFLMDK3Jse/XQsdE7yrPE0K/M0fzI5bxpM9XlSITzj dYy35XZ3bDCG51f1h9ikSgSzTR3jaKzjLgcs5tEFmQLovYCnXPJ9daFl7fRRveIE okFKpscoSnGRp+PftF9NGeusmgNoNH5T6AMSvaUNdHjzFoXD9GITNrYR5GZt/JjM jzAh9YQ2w7cEFM1AMJYVyj9DOAUvEec35fr/+nDFM3QdjJrUY6tR/GUsfxHJXdyt 6NX/L9KdXakkrrN9/4R/L3AnIqxonyaGvbOxsGt2w019xc6rFE6Ihrxp+X8xvELl JmcRF4ngOxoG6P22XBKUwkzkTXg== Received: from nasanppmta05.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3vh98m8hr9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 09 Jan 2024 19:38:04 +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 409Jc32H024616 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 9 Jan 2024 19:38:03 GMT Received: from hu-eberman-lv.qualcomm.com (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; Tue, 9 Jan 2024 11:38:02 -0800 From: Elliot Berman Date: Tue, 9 Jan 2024 11:37:59 -0800 Subject: [PATCH v16 21/34] virt: gunyah: Implement guestmemfd Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <20240109-gunyah-v16-21-634904bf4ce9@quicinc.com> References: <20240109-gunyah-v16-0-634904bf4ce9@quicinc.com> In-Reply-To: <20240109-gunyah-v16-0-634904bf4ce9@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 , "Andrew Morton" CC: , , , , , , Elliot Berman X-Mailer: b4 0.13-dev X-ClientProxiedBy: nalasex01c.na.qualcomm.com (10.47.97.35) 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-ORIG-GUID: 66cUBx-tajMGX41hKMj19ebFqRM3YAnm X-Proofpoint-GUID: 66cUBx-tajMGX41hKMj19ebFqRM3YAnm 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_02,2023-12-07_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 spamscore=0 mlxscore=0 priorityscore=1501 phishscore=0 malwarescore=0 mlxlogscore=999 suspectscore=0 clxscore=1015 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2311290000 definitions=main-2401090158 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 | 279 ++++++++++++++++++++++++++++++++++++++ drivers/virt/gunyah/vm_mgr.c | 9 ++ drivers/virt/gunyah/vm_mgr.h | 2 + include/uapi/linux/gunyah.h | 19 +++ 5 files changed, 310 insertions(+), 1 deletion(-) diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile index a6c6f29b887a..c4505fce177d 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..73a3f1368081 --- /dev/null +++ b/drivers/virt/gunyah/guest_memfd.c @@ -0,0 +1,279 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2023-2024 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#define pr_fmt(fmt) "gunyah_guest_mem: " fmt + +#include +#include +#include +#include +#include +#include + +#include + +#include "vm_mgr.h" + +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; +} + +/** + * gunyah_gmem_punch_hole() - try to reclaim a range of pages + * @inode: guest memfd inode + * @offset: Offset into memfd to start reclaim + * @len: length to reclaim + * + * Will try to unmap from virtual machines any folios covered by + * [offset, offset+len]. If unmapped, then tries to free those folios + * + * Returns - error code if any folio in the range couldn't be freed. + */ +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) +{ + 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); + /* 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 26b6dce49970..33751d5cddd2 100644 --- a/drivers/virt/gunyah/vm_mgr.c +++ b/drivers/virt/gunyah/vm_mgr.c @@ -687,6 +687,15 @@ 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 e500f6eb014e..055990842959 100644 --- a/drivers/virt/gunyah/vm_mgr.h +++ b/drivers/virt/gunyah/vm_mgr.h @@ -109,4 +109,6 @@ int gunyah_vm_provide_folio(struct gunyah_vm *ghvm, struct folio *folio, int gunyah_vm_reclaim_folio(struct gunyah_vm *ghvm, u64 gfn); int gunyah_vm_reclaim_range(struct gunyah_vm *ghvm, u64 gfn, u64 nr); +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) */