[v2,2/3] xen/privcmd: Add IOCTL_PRIVCMD_DM_OP

Message ID	1486736677-10953-3-git-send-email-paul.durrant@citrix.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <xen-devel-bounces@lists.xen.org> From: Paul Durrant <paul.durrant@citrix.com> To: <xen-devel@lists.xenproject.org>, <linux-kernel@vger.kernel.org> Date: Fri, 10 Feb 2017 14:24:36 +0000 Message-ID: <1486736677-10953-3-git-send-email-paul.durrant@citrix.com> In-Reply-To: <1486736677-10953-1-git-send-email-paul.durrant@citrix.com> References: <1486736677-10953-1-git-send-email-paul.durrant@citrix.com> MIME-Version: 1.0 Cc: Juergen Gross <jgross@suse.com>, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Paul Durrant <paul.durrant@citrix.com> Subject: [Xen-devel] [PATCH v2 2/3] xen/privcmd: Add IOCTL_PRIVCMD_DM_OP Precedence: list Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" <xen-devel-bounces@lists.xen.org>

diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h index a12a047..f6d20f6 100644 --- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -472,6 +472,13 @@ HYPERVISOR_xenpmu_op(unsigned int op, void *arg) return _hypercall2(int, xenpmu_op, op, arg); } +static inline int +HYPERVISOR_dm_op( + domid_t dom, unsigned int nr_bufs, void *bufs) +{ + return _hypercall3(int, dm_op, dom, nr_bufs, bufs); +} + static inline void MULTI_fpu_taskswitch(struct multicall_entry *mcl, int set) { diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index 5e5c7ae..d5cf042 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -32,6 +32,7 @@ #include <xen/xen.h> #include <xen/privcmd.h> #include <xen/interface/xen.h> +#include <xen/interface/hvm/dm_op.h> #include <xen/features.h> #include <xen/page.h> #include <xen/xen-ops.h> @@ -548,6 +549,139 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version) goto out; } +static int lock_pages( + struct privcmd_dm_op_buf kbufs[], unsigned int num, + struct page *pages[], unsigned int nr_pages) +{ + unsigned int i; + + for (i = 0; i < num; i++) { + unsigned int requested; + int pinned; + + requested = DIV_ROUND_UP( + offset_in_page(kbufs[i].uptr) + kbufs[i].size, + PAGE_SIZE); + if (requested > nr_pages) + return -ENOSPC; + + pinned = get_user_pages_fast( + (unsigned long) kbufs[i].uptr, + requested, FOLL_WRITE, pages); + if (pinned < 0) + return pinned; + + nr_pages -= pinned; + pages += pinned; + } + + return 0; +} + +static void unlock_pages(struct page *pages[], unsigned int nr_pages) +{ + unsigned int i; + + if (!pages) + return; + + for (i = 0; i < nr_pages; i++) { + if (pages[i]) + put_page(pages[i]); + } +} + +static long privcmd_ioctl_dm_op(void __user *udata) +{ + struct privcmd_dm_op kdata; + struct privcmd_dm_op_buf *kbufs; + unsigned int nr_pages = 0; + struct page **pages = NULL; + struct xen_dm_op_buf *xbufs = NULL; + unsigned int i; + long rc; + + if (copy_from_user(&kdata, udata, sizeof(kdata))) + return -EFAULT; + + if (kdata.num == 0) + return 0; + + /* + * Set a tolerable upper limit on the number of buffers + * without being overly restrictive, since we can't easily + * predict what future dm_ops may require. + */ + if (kdata.num * sizeof(*kbufs) > PAGE_SIZE) + return -E2BIG; + + kbufs = kcalloc(kdata.num, sizeof(*kbufs), GFP_KERNEL); + if (!kbufs) + return -ENOMEM; + + if (copy_from_user(kbufs, kdata.ubufs, + sizeof(*kbufs) * kdata.num)) { + rc = -EFAULT; + goto out; + } + + for (i = 0; i < kdata.num; i++) { + if (!access_ok(VERIFY_WRITE, kbufs[i].uptr, + kbufs[i].size)) { + rc = -EFAULT; + goto out; + } + + nr_pages += DIV_ROUND_UP( + offset_in_page(kbufs[i].uptr) + kbufs[i].size, + PAGE_SIZE); + } + + /* + * Again, set a tolerable upper limit on the number of pages + * needed to lock all the buffers without being overly + * restrictive, since we can't easily predict the size of + * buffers future dm_ops may use. + */ + if (nr_pages * sizeof(*pages) > PAGE_SIZE) { + rc = -E2BIG; + goto out; + } + + pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL); + if (!pages) { + rc = -ENOMEM; + goto out; + } + + xbufs = kcalloc(kdata.num, sizeof(*xbufs), GFP_KERNEL); + if (!xbufs) { + rc = -ENOMEM; + goto out; + } + + rc = lock_pages(kbufs, kdata.num, pages, nr_pages); + if (rc) + goto out; + + for (i = 0; i < kdata.num; i++) { + set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr); + xbufs[i].size = kbufs[i].size; + } + + xen_preemptible_hcall_begin(); + rc = HYPERVISOR_dm_op(kdata.dom, kdata.num, xbufs); + xen_preemptible_hcall_end(); + +out: + unlock_pages(pages, nr_pages); + kfree(xbufs); + kfree(pages); + kfree(kbufs); + + return rc; +} + static long privcmd_ioctl(struct file *file, unsigned int cmd, unsigned long data) { @@ -571,6 +705,10 @@ static long privcmd_ioctl(struct file *file, ret = privcmd_ioctl_mmap_batch(udata, 2); break; + case IOCTL_PRIVCMD_DM_OP: + ret = privcmd_ioctl_dm_op(udata); + break; + default: break; } diff --git a/include/uapi/xen/privcmd.h b/include/uapi/xen/privcmd.h index 7ddeeda..f8c5d75 100644 --- a/include/uapi/xen/privcmd.h +++ b/include/uapi/xen/privcmd.h @@ -77,6 +77,17 @@ struct privcmd_mmapbatch_v2 { int __user *err; /* array of error codes */ }; +struct privcmd_dm_op_buf { + void __user *uptr; + size_t size; +}; + +struct privcmd_dm_op { + domid_t dom; + __u16 num; + const struct privcmd_dm_op_buf __user *ubufs; +}; + /* * @cmd: IOCTL_PRIVCMD_HYPERCALL * @arg: &privcmd_hypercall_t @@ -98,5 +109,7 @@ struct privcmd_mmapbatch_v2 { _IOC(_IOC_NONE, 'P', 3, sizeof(struct privcmd_mmapbatch)) #define IOCTL_PRIVCMD_MMAPBATCH_V2 \ _IOC(_IOC_NONE, 'P', 4, sizeof(struct privcmd_mmapbatch_v2)) +#define IOCTL_PRIVCMD_DM_OP \ + _IOC(_IOC_NONE, 'P', 5, sizeof(struct privcmd_dm_op)) #endif /* __LINUX_PUBLIC_PRIVCMD_H__ */ diff --git a/include/xen/interface/hvm/dm_op.h b/include/xen/interface/hvm/dm_op.h new file mode 100644 index 0000000..ee9e480 --- /dev/null +++ b/include/xen/interface/hvm/dm_op.h @@ -0,0 +1,32 @@ +/* + * Copyright (c) 2016, Citrix Systems Inc + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#ifndef __XEN_PUBLIC_HVM_DM_OP_H__ +#define __XEN_PUBLIC_HVM_DM_OP_H__ + +struct xen_dm_op_buf { + GUEST_HANDLE(void) h; + xen_ulong_t size; +}; +DEFINE_GUEST_HANDLE_STRUCT(xen_dm_op_buf); + +#endif /* __XEN_PUBLIC_HVM_DM_OP_H__ */ diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h index 1b0d189..4f4830e 100644 --- a/include/xen/interface/xen.h +++ b/include/xen/interface/xen.h @@ -81,6 +81,7 @@ #define __HYPERVISOR_tmem_op 38 #define __HYPERVISOR_xc_reserved_op 39 /* reserved for XenClient */ #define __HYPERVISOR_xenpmu_op 40 +#define __HYPERVISOR_dm_op 41 /* Architecture-specific hypercall definitions. */ #define __HYPERVISOR_arch_0 48

[v2,2/3] xen/privcmd: Add IOCTL_PRIVCMD_DM_OP

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