From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59560) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bwKXs-0003vN-Dv for qemu-devel@nongnu.org; Mon, 17 Oct 2016 22:54:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bwKXp-0003mp-BJ for qemu-devel@nongnu.org; Mon, 17 Oct 2016 22:54:28 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:58530) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1bwKXp-0003mE-30 for qemu-devel@nongnu.org; Mon, 17 Oct 2016 22:54:25 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u9I2sMhh007708 for ; Mon, 17 Oct 2016 22:54:22 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0a-001b2d01.pphosted.com with ESMTP id 26579uh94r-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 17 Oct 2016 22:54:22 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 17 Oct 2016 20:54:17 -0600 Date: Tue, 18 Oct 2016 10:54:11 +0800 From: Dong Jia Shi References: <1476739332-4911-1-git-send-email-kwankhede@nvidia.com> <1476739332-4911-13-git-send-email-kwankhede@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1476739332-4911-13-git-send-email-kwankhede@nvidia.com> Message-Id: <20161018025411.GA22572@bjsdjshi@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH v9 12/12] docs: Sample driver to demonstrate how to use Mediated device framework. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kirti Wankhede Cc: alex.williamson@redhat.com, pbonzini@redhat.com, kraxel@redhat.com, cjia@nvidia.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, kevin.tian@intel.com, jike.song@intel.com, bjsdjshi@linux.vnet.ibm.com, linux-kernel@vger.kernel.org * Kirti Wankhede [2016-10-18 02:52:12 +0530]: ...snip... > +static ssize_t mdev_access(struct mdev_device *mdev, char *buf, > + size_t count, loff_t pos, bool is_write) > +{ > + struct mdev_state *mdev_state; > + unsigned int index; > + loff_t offset; > + int ret = 0; > + > + if (!mdev || !buf) > + return -EINVAL; > + > + mdev_state = mdev_get_drvdata(mdev); > + if (!mdev_state) { > + pr_err("%s mdev_state not found\n", __func__); > + return -EINVAL; > + } > + > + mutex_lock(&mdev_state->ops_lock); > + > + index = MTTY_VFIO_PCI_OFFSET_TO_INDEX(pos); > + offset = pos & MTTY_VFIO_PCI_OFFSET_MASK; > + switch (index) { > + case VFIO_PCI_CONFIG_REGION_INDEX: > + > +#if defined(DEBUG) > + pr_info("%s: PCI config space %s at offset 0x%llx\n", > + __func__, is_write ? "write" : "read", offset); > +#endif > + if (is_write) { > + dump_buffer(buf, count); > + handle_pci_cfg_write(mdev_state, offset, buf, count); > + } else { > + memcpy(buf, (mdev_state->vconfig + offset), count); > + dump_buffer(buf, count); Dear Kirti: Shouldn't we use copy_from_user instead of memcpy on @buf here? And I'm wondering if dump_buffer could really work since it tries to dereference a *__user* marked pointor. Otherwise, this is a good example driver. Thanks! > + } > + > + break; > + > + case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX: > + if (!mdev_state->region_info[index].start) > + mdev_read_base(mdev_state); > + > + if (is_write) { > + dump_buffer(buf, count); > + > +#if defined(DEBUG_REGS) > + pr_info("%s: BAR%d WR @0x%llx %s val:0x%02x dlab:%d\n", > + __func__, index, offset, wr_reg[offset], > + (u8)*buf, mdev_state->s[index].dlab); > +#endif > + handle_bar_write(index, mdev_state, offset, buf, count); > + } else { > + handle_bar_read(index, mdev_state, offset, buf, count); > + dump_buffer(buf, count); > + > +#if defined(DEBUG_REGS) > + pr_info("%s: BAR%d RD @0x%llx %s val:0x%02x dlab:%d\n", > + __func__, index, offset, rd_reg[offset], > + (u8)*buf, mdev_state->s[index].dlab); > +#endif > + } > + break; > + > + default: > + ret = -1; > + goto accessfailed; > + } > + > + ret = count; > + > + > +accessfailed: > + mutex_unlock(&mdev_state->ops_lock); > + > + return ret; > +} > + ...snip... > +ssize_t mtty_read(struct mdev_device *mdev, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + return mdev_access(mdev, buf, count, *ppos, false); > +} > + > +ssize_t mtty_write(struct mdev_device *mdev, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + return mdev_access(mdev, (char *)buf, count, *ppos, true); > +} > + ...snip... -- Dong Jia