From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755970AbdCGSyn (ORCPT ); Tue, 7 Mar 2017 13:54:43 -0500 Received: from foss.arm.com ([217.140.101.70]:51524 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751935AbdCGSym (ORCPT ); Tue, 7 Mar 2017 13:54:42 -0500 Subject: Re: [Xen-devel] [PATCH 4/7] xen/9pfs: connect to the backend To: Stefano Stabellini , xen-devel@lists.xenproject.org References: <1488830488-18506-1-git-send-email-sstabellini@kernel.org> <1488830488-18506-4-git-send-email-sstabellini@kernel.org> Cc: jgross@suse.com, Latchesar Ionkov , Eric Van Hensbergen , linux-kernel@vger.kernel.org, Stefano Stabellini , v9fs-developer@lists.sourceforge.net, Ron Minnich , boris.ostrovsky@oracle.com From: Julien Grall Message-ID: Date: Tue, 7 Mar 2017 17:37:41 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <1488830488-18506-4-git-send-email-sstabellini@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Stefano, On 03/06/2017 08:01 PM, Stefano Stabellini wrote: > +static int xen_9pfs_front_alloc_dataring(struct xenbus_device *dev, > + struct xen_9pfs_dataring *ring) > +{ > + int i; > + int ret = -ENOMEM; > + > + init_waitqueue_head(&ring->wq); > + spin_lock_init(&ring->lock); > + INIT_WORK(&ring->work, p9_xen_response); > + > + ring->intf = (struct xen_9pfs_data_intf *) __get_free_page(GFP_KERNEL | __GFP_ZERO); > + if (!ring->intf) > + goto error; > + memset(ring->intf, 0, XEN_PAGE_SIZE); > + ring->bytes = (void*)__get_free_pages(GFP_KERNEL | __GFP_ZERO, XEN_9PFS_RING_ORDER); The ring order will be in term of Xen page size and not Linux. So you are going to allocate much more memory than expected on 64KB kernel. > + if (ring->bytes == NULL) > + goto error; > + for (i = 0; i < (1 << XEN_9PFS_RING_ORDER); i++) > + ring->intf->ref[i] = gnttab_grant_foreign_access(dev->otherend_id, pfn_to_gfn(virt_to_pfn((void*)ring->bytes) + i), 0);. Please use virt_to_gfn rather than pfn_to_gfn(virt_to_pfn). Also, this is not going to work on 64K kernel because you will grant access to noncontiguous memory (e.g 0-4K, 64K-68K,...). We have various helper to break-down the page for you, see gnttab_for_one_grant, gnttab_foreach_grant, gnttab_count_grant, xen_for_each_gfn (though this one it is internal to xlate_mmu.c so far) Please use them to avoid any further. > + ring->ref = gnttab_grant_foreign_access(dev->otherend_id, pfn_to_gfn(virt_to_pfn((void*)ring->intf)), 0); Please use virt_to_gfn rather than pfn_to_gfn(virt_to_pfn). > + ring->ring.in = ring->bytes; > + ring->ring.out = ring->bytes + XEN_9PFS_RING_SIZE; > + > + ret = xenbus_alloc_evtchn(dev, &ring->evtchn); > + if (ret) > + goto error; > + ring->irq = bind_evtchn_to_irqhandler(ring->evtchn, xen_9pfs_front_event_handler, > + 0, "xen_9pfs-frontend", ring); > + if (ring->irq < 0) { > + xenbus_free_evtchn(dev, ring->evtchn); > + ret = ring->irq; > + goto error; > + } > return 0; > + > +error: > + if (ring->intf != NULL) > + kfree(ring->intf); > + if (ring->bytes != NULL) > + kfree(ring->bytes); > + return ret; > } Cheers, -- Julien Grall From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH 4/7] xen/9pfs: connect to the backend Date: Tue, 7 Mar 2017 17:37:41 +0000 Message-ID: References: <1488830488-18506-1-git-send-email-sstabellini@kernel.org> <1488830488-18506-4-git-send-email-sstabellini@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: Received: from mail6.bemta6.messagelabs.com ([193.109.254.103]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1clJ3V-0005EM-Rg for xen-devel@lists.xenproject.org; Tue, 07 Mar 2017 17:37:49 +0000 In-Reply-To: <1488830488-18506-4-git-send-email-sstabellini@kernel.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Stefano Stabellini , xen-devel@lists.xenproject.org Cc: jgross@suse.com, Latchesar Ionkov , Eric Van Hensbergen , linux-kernel@vger.kernel.org, Stefano Stabellini , Ron Minnich , v9fs-developer@lists.sourceforge.net, boris.ostrovsky@oracle.com List-Id: xen-devel@lists.xenproject.org SGkgU3RlZmFubywKCk9uIDAzLzA2LzIwMTcgMDg6MDEgUE0sIFN0ZWZhbm8gU3RhYmVsbGluaSB3 cm90ZToKPiArc3RhdGljIGludCB4ZW5fOXBmc19mcm9udF9hbGxvY19kYXRhcmluZyhzdHJ1Y3Qg eGVuYnVzX2RldmljZSAqZGV2LAo+ICsJCXN0cnVjdCB4ZW5fOXBmc19kYXRhcmluZyAqcmluZykK PiArewo+ICsJaW50IGk7Cj4gKwlpbnQgcmV0ID0gLUVOT01FTTsKPiArCj4gKwlpbml0X3dhaXRx dWV1ZV9oZWFkKCZyaW5nLT53cSk7Cj4gKwlzcGluX2xvY2tfaW5pdCgmcmluZy0+bG9jayk7Cj4g KwlJTklUX1dPUksoJnJpbmctPndvcmssIHA5X3hlbl9yZXNwb25zZSk7Cj4gKwo+ICsJcmluZy0+ aW50ZiA9IChzdHJ1Y3QgeGVuXzlwZnNfZGF0YV9pbnRmICopIF9fZ2V0X2ZyZWVfcGFnZShHRlBf S0VSTkVMIHwgX19HRlBfWkVSTyk7Cj4gKwlpZiAoIXJpbmctPmludGYpCj4gKwkJZ290byBlcnJv cjsKPiArCW1lbXNldChyaW5nLT5pbnRmLCAwLCBYRU5fUEFHRV9TSVpFKTsKPiArCXJpbmctPmJ5 dGVzID0gKHZvaWQqKV9fZ2V0X2ZyZWVfcGFnZXMoR0ZQX0tFUk5FTCB8IF9fR0ZQX1pFUk8sIFhF Tl85UEZTX1JJTkdfT1JERVIpOwoKVGhlIHJpbmcgb3JkZXIgd2lsbCBiZSBpbiB0ZXJtIG9mIFhl biBwYWdlIHNpemUgYW5kIG5vdCBMaW51eC4gU28geW91IAphcmUgZ29pbmcgdG8gYWxsb2NhdGUg bXVjaCBtb3JlIG1lbW9yeSB0aGFuIGV4cGVjdGVkIG9uIDY0S0Iga2VybmVsLgoKPiArCWlmIChy aW5nLT5ieXRlcyA9PSBOVUxMKQo+ICsJCWdvdG8gZXJyb3I7Cj4gKwlmb3IgKGkgPSAwOyBpIDwg KDEgPDwgWEVOXzlQRlNfUklOR19PUkRFUik7IGkrKykKPiArCQlyaW5nLT5pbnRmLT5yZWZbaV0g PSBnbnR0YWJfZ3JhbnRfZm9yZWlnbl9hY2Nlc3MoZGV2LT5vdGhlcmVuZF9pZCwgcGZuX3RvX2dm bih2aXJ0X3RvX3Bmbigodm9pZCopcmluZy0+Ynl0ZXMpICsgaSksIDApOy4KClBsZWFzZSB1c2Ug dmlydF90b19nZm4gcmF0aGVyIHRoYW4gcGZuX3RvX2dmbih2aXJ0X3RvX3BmbikuCgpBbHNvLCB0 aGlzIGlzIG5vdCBnb2luZyB0byB3b3JrIG9uIDY0SyBrZXJuZWwgYmVjYXVzZSB5b3Ugd2lsbCBn cmFudCAKYWNjZXNzIHRvIG5vbmNvbnRpZ3VvdXMgbWVtb3J5IChlLmcgMC00SywgNjRLLTY4Sywu Li4pLgoKV2UgaGF2ZSB2YXJpb3VzIGhlbHBlciB0byBicmVhay1kb3duIHRoZSBwYWdlIGZvciB5 b3UsIHNlZSAKZ250dGFiX2Zvcl9vbmVfZ3JhbnQsIGdudHRhYl9mb3JlYWNoX2dyYW50LCBnbnR0 YWJfY291bnRfZ3JhbnQsIAp4ZW5fZm9yX2VhY2hfZ2ZuICh0aG91Z2ggdGhpcyBvbmUgaXQgaXMg aW50ZXJuYWwgdG8geGxhdGVfbW11LmMgc28gZmFyKQoKUGxlYXNlIHVzZSB0aGVtIHRvIGF2b2lk IGFueSBmdXJ0aGVyLgoKPiArCXJpbmctPnJlZiA9IGdudHRhYl9ncmFudF9mb3JlaWduX2FjY2Vz cyhkZXYtPm90aGVyZW5kX2lkLCBwZm5fdG9fZ2ZuKHZpcnRfdG9fcGZuKCh2b2lkKilyaW5nLT5p bnRmKSksIDApOwoKUGxlYXNlIHVzZSB2aXJ0X3RvX2dmbiByYXRoZXIgdGhhbiBwZm5fdG9fZ2Zu KHZpcnRfdG9fcGZuKS4KCj4gKwlyaW5nLT5yaW5nLmluID0gcmluZy0+Ynl0ZXM7Cj4gKwlyaW5n LT5yaW5nLm91dCA9IHJpbmctPmJ5dGVzICsgWEVOXzlQRlNfUklOR19TSVpFOwo+ICsKPiArCXJl dCA9IHhlbmJ1c19hbGxvY19ldnRjaG4oZGV2LCAmcmluZy0+ZXZ0Y2huKTsKPiArCWlmIChyZXQp Cj4gKwkJZ290byBlcnJvcjsKPiArCXJpbmctPmlycSA9IGJpbmRfZXZ0Y2huX3RvX2lycWhhbmRs ZXIocmluZy0+ZXZ0Y2huLCB4ZW5fOXBmc19mcm9udF9ldmVudF9oYW5kbGVyLAo+ICsJCQkJCTAs ICJ4ZW5fOXBmcy1mcm9udGVuZCIsIHJpbmcpOwo+ICsJaWYgKHJpbmctPmlycSA8IDApIHsKPiAr CQl4ZW5idXNfZnJlZV9ldnRjaG4oZGV2LCByaW5nLT5ldnRjaG4pOwo+ICsJCXJldCA9IHJpbmct PmlycTsKPiArCQlnb3RvIGVycm9yOwo+ICsJfQo+ICAJcmV0dXJuIDA7Cj4gKwo+ICtlcnJvcjoK PiArCWlmIChyaW5nLT5pbnRmICE9IE5VTEwpCj4gKwkJa2ZyZWUocmluZy0+aW50Zik7Cj4gKwlp ZiAocmluZy0+Ynl0ZXMgIT0gTlVMTCkKPiArCQlrZnJlZShyaW5nLT5ieXRlcyk7Cj4gKwlyZXR1 cm4gcmV0Owo+ICB9CgpDaGVlcnMsCgotLSAKSnVsaWVuIEdyYWxsCgpfX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpYZW4tZGV2ZWwgbWFpbGluZyBsaXN0Clhl bi1kZXZlbEBsaXN0cy54ZW4ub3JnCmh0dHBzOi8vbGlzdHMueGVuLm9yZy94ZW4tZGV2ZWwK