From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lu Baolu Subject: Re: [PATCH v2 3/7] iommu/vt-d: Expose ISA direct mapping region via iommu_get_resv_regions Date: Thu, 4 Apr 2019 14:49:05 +0800 Message-ID: References: <0F0C82BE-86E5-4BAC-938C-6F7629E18D27@arista.com> <83B82113-8AE5-4B0C-A079-F389520525BD@arista.com> <445F31EA-20F3-481C-B1DF-8B163791FF8C@arista.com> <6C211BF1-B5A0-4821-AB42-092B573DE667@arista.com> <8B1FC0C7-9BAC-498D-B1F0-0138EACF75C2@arista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <8B1FC0C7-9BAC-498D-B1F0-0138EACF75C2@arista.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: James Sewart Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org, Tom Murphy , Dmitry Safonov , Jacob Pan , linux-kernel@vger.kernel.org List-Id: iommu@lists.linux-foundation.org Hi James, I did a sanity test from my end. The test machine fails to boot. I haven't seen any valuable kernel log. It results in a purple screen. Best regards, Lu Baolu On 3/29/19 11:26 PM, James Sewart wrote: > Hey Lu, > > I’ve attached a preliminary v3, if you could take a look and run some tests > that would be great. > > Since v2 i’ve added your default domain type patches, the new device_group > handler, and incorporated Jacob’s feedback. > >> On 28 Mar 2019, at 18:37, James Sewart wrote: >> >> Hey Lu, >> >>> On 26 Mar 2019, at 01:24, Lu Baolu wrote: >>> >>> Hi James, >>> >>> On 3/25/19 8:57 PM, James Sewart wrote: >>>>>> Theres an issue that if we choose to alloc a new resv_region with type >>>>>> IOMMU_RESV_DIRECT, we will need to refactor intel_iommu_put_resv_regions >>>>>> to free this entry type which means refactoring the rmrr regions in >>>>>> get_resv_regions. Should this work be in this patchset? >>>>> Do you mean the rmrr regions are not allocated in get_resv_regions, but >>>>> are freed in put_resv_regions? I think we should fix this in this patch >>>>> set since this might impact the device passthrough if we don't do it. >>>> They’re not allocated and not freed currently, only type IOMMU_RESV_MSI is >>>> freed in put_resv_regions. If we allocate a new resv_region with type >>>> IOMMU_RESV_DIRECT for the isa region, then it won’t be freed. If we modify >>>> put_resv_regions to free type IOMMU_RESV_DIRECT, then we will try to free >>>> the static RMRR regions. >>>> Either the ISA region is static and not freed as with my implementation, >>>> or the RMRR regions are converted to be allocated on each call to >>>> get_resv_regions and freed in put_resv_regions. >>> >>> By the way, there's another way in my mind. Let's add a new region type >>> for LPC devices, e.x. IOMMU_RESV_LPC, and then handle it in the same way >>> as those MSI regions. Just FYI. >> >> This solution would require adding some extra code to >> iommu_group_create_direct_mappings as currently only type >> IOMMU_RESV_DIRECT is identity mapped, other types are only reserved. >> >> >>> >>> Best regards, >>> Lu Baolu >> >> Cheers, >> James. > > Cheers, > James. >