lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 7 Mar 2019 11:42:59 +0000 From: Jean-Philippe Brucker <jean-philippe.brucker@....com> To: Jacob Pan <jacob.jun.pan@...ux.intel.com> Cc: Eric Auger <eric.auger@...hat.com>, "eric.auger.pro@...il.com" <eric.auger.pro@...il.com>, "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "kvmarm@...ts.cs.columbia.edu" <kvmarm@...ts.cs.columbia.edu>, "joro@...tes.org" <joro@...tes.org>, "alex.williamson@...hat.com" <alex.williamson@...hat.com>, "yi.l.liu@...ux.intel.com" <yi.l.liu@...ux.intel.com>, Will Deacon <Will.Deacon@....com>, Robin Murphy <Robin.Murphy@....com>, Marc Zyngier <Marc.Zyngier@....com>, "peter.maydell@...aro.org" <peter.maydell@...aro.org>, "kevin.tian@...el.com" <kevin.tian@...el.com>, "ashok.raj@...el.com" <ashok.raj@...el.com>, Christoffer Dall <Christoffer.Dall@....com> Subject: Re: [PATCH v4 03/22] iommu: introduce device fault report API On 06/03/2019 23:46, Jacob Pan wrote: > On Tue, 5 Mar 2019 15:03:41 +0000 > Jean-Philippe Brucker <jean-philippe.brucker@....com> wrote: > >> On 18/02/2019 13:54, Eric Auger wrote: >> [...]> +/** >> > + * iommu_register_device_fault_handler() - Register a device fault >> > handler >> > + * @dev: the device >> > + * @handler: the fault handler >> > + * @data: private data passed as argument to the handler >> > + * >> > + * When an IOMMU fault event is received, call this handler with >> > the fault event >> > + * and data as argument. The handler should return 0 on success. >> > If the fault is >> > + * recoverable (IOMMU_FAULT_PAGE_REQ), the handler can also >> > complete >> > + * the fault by calling iommu_page_response() with one of the >> > following >> > + * response code: >> > + * - IOMMU_PAGE_RESP_SUCCESS: retry the translation >> > + * - IOMMU_PAGE_RESP_INVALID: terminate the fault >> > + * - IOMMU_PAGE_RESP_FAILURE: terminate the fault and stop >> > reporting >> > + * page faults if possible. >> >> The comment refers to function and values that haven't been defined >> yet. Either the page_response() patch should come before, or we need >> to split this patch. >> >> Something I missed before: if the handler fails (returns != 0) it >> should complete the fault by calling iommu_page_response(), if we're >> not doing it in iommu_report_device_fault(). It should be indicated >> in this comment. It's safe for the handler to call page_response() >> since we're not holding fault_param->lock when calling the handler. >> > If the page request fault is to be reported to a guest, the report > function cannot wait for the completion status. As long as the fault is > injected into the guest, the handler should complete with success. If > the PRQ report fails, IMHO, the caller of iommu_report_device_fault() > should send page_response, perhaps after clean up all partial response > of the group too. Ok, the caller (IOMMU driver) sending the page_response if iommu_report_device_fault() fails does make more sense. Agreed on the partial cleanup as well, we don't keep track of them here, but I need to add that to the io-pgfault layer. However some cleanup should probably happen in here... >> > + /* we only report device fault if there is a handler >> > registered */ >> > + mutex_lock(&dev->iommu_param->lock); >> > + if (!dev->iommu_param->fault_param || >> > + !dev->iommu_param->fault_param->handler) { >> > + ret = -EINVAL; >> > + goto done_unlock; >> > + } >> > + fparam = dev->iommu_param->fault_param; >> > + if (evt->fault.type == IOMMU_FAULT_PAGE_REQ && >> > + evt->fault.prm.flags & >> > IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE) { >> > + evt_pending = kmemdup(evt, sizeof(struct >> > iommu_fault_event), >> > + GFP_KERNEL); >> > + if (!evt_pending) { >> > + ret = -ENOMEM; >> > + goto done_unlock; >> > + } >> > + mutex_lock(&fparam->lock); >> > + list_add_tail(&evt_pending->list, &fparam->faults); >> > + mutex_unlock(&fparam->lock); >> > + } >> > + ret = fparam->handler(evt, fparam->data); ... if ret != 0, removing and freeing the pending event seems more appropriate here than asking our caller to do it Thanks, Jean >> > +done_unlock: >> > + mutex_unlock(&dev->iommu_param->lock); >> > + return ret; >> > +} >> > +EXPORT_SYMBOL_GPL(iommu_report_device_fault); >> [...] > > [Jacob Pan]
Powered by blists - more mailing lists