From patchwork Tue Oct 17 13:24:25 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 10012023 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 83F0C60235 for ; Tue, 17 Oct 2017 13:27:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 78C282884B for ; Tue, 17 Oct 2017 13:27:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6D4FF288B9; Tue, 17 Oct 2017 13:27:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A661F288AF for ; Tue, 17 Oct 2017 13:27:18 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e4RrT-0000CE-CG; Tue, 17 Oct 2017 13:24:47 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e4RrS-0000Ar-24 for xen-devel@lists.xenproject.org; Tue, 17 Oct 2017 13:24:46 +0000 Received: from [85.158.139.211] by server-7.bemta-5.messagelabs.com id A2/F8-01785-D9406E95; Tue, 17 Oct 2017 13:24:45 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrHIsWRWlGSWpSXmKPExsXitHSDve4clme RBl/a1S2+b5nM5MDocfjDFZYAxijWzLyk/IoE1owJa08wF8yJrFj8fB1LA+Nt5y5GTg4JAX+J R99XsIHYbAI6ElOfXmLtYuTgEBFQkbi916CLkYuDWWAZk8TRa3sZQWqEBWIlpi2cxQ5iswioS hw6O4MZpJ5XwEZi43lNiJHyErvaLrKC2JwCthKv/x1gBrGFgEo2zVsPFucVEJQ4OfMJC4jNLK Ap0br9NzuELS/RvHU2VL2KxPqps9gmMPLNQtIyC0nLLCQtCxiZVzFqFKcWlaUW6RoZ6iUVZaZ nlOQmZuboGhqY6uWmFhcnpqfmJCYV6yXn525iBIZaPQMD4w7Gu5P9DjFKcjApifI6Gz6JFOJL yk+pzEgszogvKs1JLT7EKMPBoSTBe5b5WaSQYFFqempFWmYOMOhh0hIcPEoivMtA0rzFBYm5x ZnpEKlTjMYcXdOu/GHi6Lh59w+TEEtefl6qlDhvGUipAEhpRmke3CBYNF5ilJUS5mVkYGAQ4i lILcrNLEGVf8UozsGoJMxrADKFJzOvBG7fK6BTmIBOWef0BOSUkkSElFQDo7Ptq82XXreu3c7 K6L5mVXxl04ZLrc/VYjV/ix3yVPm0oPpZZZt3MFu4xQkHRwXhHypVf5PCt6mHrj/QVM0uvMQ+ KEj5Tvsnqy9/utd8vnIm4ufxb2LeR24+Waa5+FzqOf7bDVrVr18ncy1Zst9COreicvvpm2l8Z XPm8bx9VvBwwfZVa3R4hJRYijMSDbWYi4oTAfNC62DBAgAA X-Env-Sender: prvs=4567f63fb=Paul.Durrant@citrix.com X-Msg-Ref: server-12.tower-206.messagelabs.com!1508246679!71073821!3 X-Originating-IP: [66.165.176.63] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni42MyA9PiAzMDYwNDg=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 9.4.45; banners=-,-,- X-VirusChecked: Checked Received: (qmail 756 invoked from network); 17 Oct 2017 13:24:44 -0000 Received: from smtp02.citrix.com (HELO SMTP02.CITRIX.COM) (66.165.176.63) by server-12.tower-206.messagelabs.com with RC4-SHA encrypted SMTP; 17 Oct 2017 13:24:44 -0000 X-IronPort-AV: E=Sophos;i="5.43,391,1503360000"; d="scan'208";a="454570831" From: Paul Durrant To: Date: Tue, 17 Oct 2017 14:24:25 +0100 Message-ID: <20171017132432.24093-5-paul.durrant@citrix.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171017132432.24093-1-paul.durrant@citrix.com> References: <20171017132432.24093-1-paul.durrant@citrix.com> MIME-Version: 1.0 Cc: Stefano Stabellini , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Paul Durrant Subject: [Xen-devel] [PATCH v12 04/11] x86/hvm/ioreq: defer mapping gfns until they are actually requsted X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP A subsequent patch will introduce a new scheme to allow an emulator to map ioreq server pages directly from Xen rather than the guest P2M. This patch lays the groundwork for that change by deferring mapping of gfns until their values are requested by an emulator. To that end, the pad field of the xen_dm_op_get_ioreq_server_info structure is re-purposed to a flags field and new flag, XEN_DMOP_no_gfns, defined which modifies the behaviour of XEN_DMOP_get_ioreq_server_info to allow the caller to avoid requesting the gfn values. Signed-off-by: Paul Durrant Reviewed-by: Roger Pau Monné Acked-by: Wei Liu Reviewed-by: Jan Beulich --- Cc: Ian Jackson Cc: Andrew Cooper Cc: George Dunlap Cc: Konrad Rzeszutek Wilk Cc: Stefano Stabellini Cc: Tim Deegan v8: - For safety make all of the pointers passed to hvm_get_ioreq_server_info() optional. - Shrink bufioreq_handling down to a uint8_t. v3: - Updated in response to review comments from Wei and Roger. - Added a HANDLE_BUFIOREQ macro to make the code neater. - This patch no longer introduces a security vulnerability since there is now an explicit limit on the number of ioreq servers that may be created for any one domain. --- tools/libs/devicemodel/core.c | 8 +++++ tools/libs/devicemodel/include/xendevicemodel.h | 6 ++-- xen/arch/x86/hvm/dm.c | 9 +++-- xen/arch/x86/hvm/ioreq.c | 47 ++++++++++++++----------- xen/include/asm-x86/hvm/domain.h | 2 +- xen/include/public/hvm/dm_op.h | 32 ++++++++++------- 6 files changed, 63 insertions(+), 41 deletions(-) diff --git a/tools/libs/devicemodel/core.c b/tools/libs/devicemodel/core.c index 0f2c1a791f..91c69d103b 100644 --- a/tools/libs/devicemodel/core.c +++ b/tools/libs/devicemodel/core.c @@ -188,6 +188,14 @@ int xendevicemodel_get_ioreq_server_info( data->id = id; + /* + * If the caller is not requesting gfn values then instruct the + * hypercall not to retrieve them as this may cause them to be + * mapped. + */ + if (!ioreq_gfn && !bufioreq_gfn) + data->flags |= XEN_DMOP_no_gfns; + rc = xendevicemodel_op(dmod, domid, 1, &op, sizeof(op)); if (rc) return rc; diff --git a/tools/libs/devicemodel/include/xendevicemodel.h b/tools/libs/devicemodel/include/xendevicemodel.h index 13216db04a..d73a76da35 100644 --- a/tools/libs/devicemodel/include/xendevicemodel.h +++ b/tools/libs/devicemodel/include/xendevicemodel.h @@ -61,11 +61,11 @@ int xendevicemodel_create_ioreq_server( * @parm domid the domain id to be serviced * @parm id the IOREQ Server id. * @parm ioreq_gfn pointer to a xen_pfn_t to receive the synchronous ioreq - * gfn + * gfn. (May be NULL if not required) * @parm bufioreq_gfn pointer to a xen_pfn_t to receive the buffered ioreq - * gfn + * gfn. (May be NULL if not required) * @parm bufioreq_port pointer to a evtchn_port_t to receive the buffered - * ioreq event channel + * ioreq event channel. (May be NULL if not required) * @return 0 on success, -1 on failure. */ int xendevicemodel_get_ioreq_server_info( diff --git a/xen/arch/x86/hvm/dm.c b/xen/arch/x86/hvm/dm.c index 9cf53b551c..22fa5b51e3 100644 --- a/xen/arch/x86/hvm/dm.c +++ b/xen/arch/x86/hvm/dm.c @@ -416,16 +416,19 @@ static int dm_op(const struct dmop_args *op_args) { struct xen_dm_op_get_ioreq_server_info *data = &op.u.get_ioreq_server_info; + const uint16_t valid_flags = XEN_DMOP_no_gfns; const_op = false; rc = -EINVAL; - if ( data->pad ) + if ( data->flags & ~valid_flags ) break; rc = hvm_get_ioreq_server_info(d, data->id, - &data->ioreq_gfn, - &data->bufioreq_gfn, + (data->flags & XEN_DMOP_no_gfns) ? + NULL : &data->ioreq_gfn, + (data->flags & XEN_DMOP_no_gfns) ? + NULL : &data->bufioreq_gfn, &data->bufioreq_port); break; } diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c index 64bb13cec9..f654e7796c 100644 --- a/xen/arch/x86/hvm/ioreq.c +++ b/xen/arch/x86/hvm/ioreq.c @@ -350,6 +350,9 @@ static void hvm_update_ioreq_evtchn(struct hvm_ioreq_server *s, } } +#define HANDLE_BUFIOREQ(s) \ + ((s)->bufioreq_handling != HVM_IOREQSRV_BUFIOREQ_OFF) + static int hvm_ioreq_server_add_vcpu(struct hvm_ioreq_server *s, struct vcpu *v) { @@ -371,7 +374,7 @@ static int hvm_ioreq_server_add_vcpu(struct hvm_ioreq_server *s, sv->ioreq_evtchn = rc; - if ( v->vcpu_id == 0 && s->bufioreq.va != NULL ) + if ( v->vcpu_id == 0 && HANDLE_BUFIOREQ(s) ) { struct domain *d = s->domain; @@ -422,7 +425,7 @@ static void hvm_ioreq_server_remove_vcpu(struct hvm_ioreq_server *s, list_del(&sv->list_entry); - if ( v->vcpu_id == 0 && s->bufioreq.va != NULL ) + if ( v->vcpu_id == 0 && HANDLE_BUFIOREQ(s) ) free_xen_event_channel(v->domain, s->bufioreq_evtchn); free_xen_event_channel(v->domain, sv->ioreq_evtchn); @@ -449,7 +452,7 @@ static void hvm_ioreq_server_remove_all_vcpus(struct hvm_ioreq_server *s) list_del(&sv->list_entry); - if ( v->vcpu_id == 0 && s->bufioreq.va != NULL ) + if ( v->vcpu_id == 0 && HANDLE_BUFIOREQ(s) ) free_xen_event_channel(v->domain, s->bufioreq_evtchn); free_xen_event_channel(v->domain, sv->ioreq_evtchn); @@ -460,14 +463,13 @@ static void hvm_ioreq_server_remove_all_vcpus(struct hvm_ioreq_server *s) spin_unlock(&s->lock); } -static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s, - bool handle_bufioreq) +static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s) { int rc; rc = hvm_map_ioreq_gfn(s, false); - if ( !rc && handle_bufioreq ) + if ( !rc && HANDLE_BUFIOREQ(s) ) rc = hvm_map_ioreq_gfn(s, true); if ( rc ) @@ -597,13 +599,7 @@ static int hvm_ioreq_server_init(struct hvm_ioreq_server *s, if ( rc ) return rc; - if ( bufioreq_handling == HVM_IOREQSRV_BUFIOREQ_ATOMIC ) - s->bufioreq_atomic = true; - - rc = hvm_ioreq_server_map_pages( - s, bufioreq_handling != HVM_IOREQSRV_BUFIOREQ_OFF); - if ( rc ) - goto fail_map; + s->bufioreq_handling = bufioreq_handling; for_each_vcpu ( d, v ) { @@ -618,9 +614,6 @@ static int hvm_ioreq_server_init(struct hvm_ioreq_server *s, hvm_ioreq_server_remove_all_vcpus(s); hvm_ioreq_server_unmap_pages(s); - fail_map: - hvm_ioreq_server_free_rangesets(s); - return rc; } @@ -757,12 +750,23 @@ int hvm_get_ioreq_server_info(struct domain *d, ioservid_t id, ASSERT(!IS_DEFAULT(s)); - *ioreq_gfn = gfn_x(s->ioreq.gfn); + if ( ioreq_gfn || bufioreq_gfn ) + { + rc = hvm_ioreq_server_map_pages(s); + if ( rc ) + goto out; + } - if ( s->bufioreq.va != NULL ) + if ( ioreq_gfn ) + *ioreq_gfn = gfn_x(s->ioreq.gfn); + + if ( HANDLE_BUFIOREQ(s) ) { - *bufioreq_gfn = gfn_x(s->bufioreq.gfn); - *bufioreq_port = s->bufioreq_evtchn; + if ( bufioreq_gfn ) + *bufioreq_gfn = gfn_x(s->bufioreq.gfn); + + if ( bufioreq_port ) + *bufioreq_port = s->bufioreq_evtchn; } rc = 0; @@ -1264,7 +1268,8 @@ static int hvm_send_buffered_ioreq(struct hvm_ioreq_server *s, ioreq_t *p) pg->ptrs.write_pointer += qw ? 2 : 1; /* Canonicalize read/write pointers to prevent their overflow. */ - while ( s->bufioreq_atomic && qw++ < IOREQ_BUFFER_SLOT_NUM && + while ( (s->bufioreq_handling == HVM_IOREQSRV_BUFIOREQ_ATOMIC) && + qw++ < IOREQ_BUFFER_SLOT_NUM && pg->ptrs.read_pointer >= IOREQ_BUFFER_SLOT_NUM ) { union bufioreq_pointers old = pg->ptrs, new; diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h index 3bd9c5d7c0..8b798ee4e9 100644 --- a/xen/include/asm-x86/hvm/domain.h +++ b/xen/include/asm-x86/hvm/domain.h @@ -69,7 +69,7 @@ struct hvm_ioreq_server { evtchn_port_t bufioreq_evtchn; struct rangeset *range[NR_IO_RANGE_TYPES]; bool enabled; - bool bufioreq_atomic; + uint8_t bufioreq_handling; }; /* diff --git a/xen/include/public/hvm/dm_op.h b/xen/include/public/hvm/dm_op.h index 6bbab5fca3..9677bd74e7 100644 --- a/xen/include/public/hvm/dm_op.h +++ b/xen/include/public/hvm/dm_op.h @@ -79,28 +79,34 @@ struct xen_dm_op_create_ioreq_server { * XEN_DMOP_get_ioreq_server_info: Get all the information necessary to * access IOREQ Server . * - * The emulator needs to map the synchronous ioreq structures and buffered - * ioreq ring (if it exists) that Xen uses to request emulation. These are - * hosted in the target domain's gmfns and - * respectively. In addition, if the IOREQ Server is handling buffered - * emulation requests, the emulator needs to bind to event channel - * to listen for them. (The event channels used for - * synchronous emulation requests are specified in the per-CPU ioreq - * structures in ). - * If the IOREQ Server is not handling buffered emulation requests then the - * values handed back in and will both be 0. + * If the IOREQ Server is handling buffered emulation requests, the + * emulator needs to bind to event channel to listen for + * them. (The event channels used for synchronous emulation requests are + * specified in the per-CPU ioreq structures). + * In addition, if the XENMEM_acquire_resource memory op cannot be used, + * the emulator will need to map the synchronous ioreq structures and + * buffered ioreq ring (if it exists) from guest memory. If does + * not contain XEN_DMOP_no_gfns then these pages will be made available and + * the frame numbers passed back in gfns and + * respectively. (If the IOREQ Server is not handling buffered emulation + * only will be valid). */ #define XEN_DMOP_get_ioreq_server_info 2 struct xen_dm_op_get_ioreq_server_info { /* IN - server id */ ioservid_t id; - uint16_t pad; + /* IN - flags */ + uint16_t flags; + +#define _XEN_DMOP_no_gfns 0 +#define XEN_DMOP_no_gfns (1u << _XEN_DMOP_no_gfns) + /* OUT - buffered ioreq port */ evtchn_port_t bufioreq_port; - /* OUT - sync ioreq gfn */ + /* OUT - sync ioreq gfn (see block comment above) */ uint64_aligned_t ioreq_gfn; - /* OUT - buffered ioreq gfn */ + /* OUT - buffered ioreq gfn (see block comment above)*/ uint64_aligned_t bufioreq_gfn; };