From: Julien Grall <julien@xen.org>
To: Rahul Singh <Rahul.Singh@arm.com>,
Stefano Stabellini <sstabellini@kernel.org>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Bertrand Marquis <Bertrand.Marquis@arm.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Jan Beulich <jbeulich@suse.com>,
Wei Liu <wl@xen.org>, Paul Durrant <paul@xen.org>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: Re: [PATCH v5 10/10] xen/arm: smmuv3: Add support for SMMUv3 driver
Date: Thu, 21 Jan 2021 18:43:10 +0000 [thread overview]
Message-ID: <81104729-0354-f479-9329-04447df1b096@xen.org> (raw)
In-Reply-To: <9621B25B-E39A-4354-9AA3-1ECAED21B8B2@arm.com>
Hi Rahul,
Please try to trim the e-mail when quoting, otherwise it is quite
difficult to find the only couple of answer you wrote.
On 21/01/2021 17:10, Rahul Singh wrote:
>> On 20 Jan 2021, at 8:31 pm, Stefano Stabellini <sstabellini@kernel.org> wrote:
>>> -static void __iomem *arm_smmu_ioremap(struct device *dev, resource_size_t start,
>>> - resource_size_t size)
>>> +
>>> +static void arm_smmu_free_structures(struct arm_smmu_device *smmu)
>>> {
>>> - struct resource res = {
>>> - .flags = IORESOURCE_MEM,
>>> - .start = start,
>>> - .end = start + size - 1,
>>> - };
>>> + if (smmu->cmdq.q.base)
>>> + xfree(smmu->cmdq.q.base);
>>> +
>>> + if (smmu->evtq.q.base)
>>> + xfree(smmu->evtq.q.base);
>>>
>>> - return devm_ioremap_resource(dev, &res);
>>> + if (smmu->priq.q.base)
>>> + xfree(smmu->priq.q.base);
>>> +
>>> + if (smmu->strtab_cfg.strtab)
>>> + xfree(smmu->strtab_cfg.strtab);
>>> +
>>> + if (smmu->strtab_cfg.l1_desc)
>>> + xfree(smmu->strtab_cfg.l1_desc);
>>
>> From what I can tell we also need to free somewhere
>> smmu->strtab_cfg->l1_desc->l2ptr allocated by arm_smmu_init_l2_strtab
>
> "l1_desc->l2ptr" is a pointer to the Level 1 Stream Table Descriptor if 2-level Stream Table supported.
>
> If the device is protected by IOMMU, SMMUv3 driver will allocate the "l1_desc->l2ptr” when the device is added to the IOMMU via arm_smmu_add_device() function and device will be configured in bypass/abort mode.
>
> Once we assign the device to the domain(arm_smmu_assign_dev() ) smmuv3 hw will be configured correctly to match the StreamID. If there is a failure in assigning the device, that case also XEN will not remove the device and master device still be in bypass/abort mode.
I am a bit confused with this answer. Wouldn't this mean that we are
"leaking" memory if we fail to assign the device?
>
> As in XEN, there is no function to remove the master device from the IOMMU, because of that I feel there is no need to free the "l1_desc->l2ptr” in case of failure also.
Hmmm... Xen is able to remove device from the IOMMU. The reason this is
not implemented yet on Arm is because you can't hot-unplug "platform"
device.
I expect the removal function to be useful for PCI.
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2021-01-21 18:43 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 14:52 [PATCH v5 00/10] xen/arm: Add support for SMMUv3 driver Rahul Singh
2021-01-20 14:52 ` [PATCH v5 01/10] xen/arm: smmuv3: Import the SMMUv3 driver from Linux Rahul Singh
2021-01-20 14:52 ` [PATCH v5 02/10] xen/arm: Revert atomic operation related command-queue insertion patch Rahul Singh
2021-01-20 14:52 ` [PATCH v5 03/10] xen/arm: smmuv3: Revert patch related to XArray Rahul Singh
2021-01-20 14:52 ` [PATCH v5 04/10] xen/arm: smmuv3: Remove support for Stage-1 translation on SMMUv3 Rahul Singh
2021-01-20 14:52 ` [PATCH v5 05/10] xen/arm: smmuv3: Remove Linux specific code that is not usable in XEN Rahul Singh
2021-01-20 14:52 ` [PATCH v5 06/10] xen/device-tree: Add dt_property_match_string helper Rahul Singh
2021-01-20 14:52 ` [PATCH v5 07/10] xen/compiler: import 'fallthrough' keyword from linux Rahul Singh
2021-01-20 14:52 ` [PATCH v5 08/10] xen/arm: smmuv3: Use fallthrough pseudo-keyword Rahul Singh
2021-01-20 15:36 ` Bertrand Marquis
2021-01-20 19:56 ` Stefano Stabellini
2021-01-20 14:52 ` [PATCH v5 09/10] xen/arm: smmuv3: Replace linux functions with xen functions Rahul Singh
2021-01-20 14:52 ` [PATCH v5 10/10] xen/arm: smmuv3: Add support for SMMUv3 driver Rahul Singh
2021-01-20 15:35 ` Bertrand Marquis
2021-01-20 20:31 ` Stefano Stabellini
2021-01-21 17:10 ` Rahul Singh
2021-01-21 18:43 ` Julien Grall [this message]
2021-01-21 20:28 ` Rahul Singh
2021-01-21 21:20 ` Stefano Stabellini
2021-01-20 21:33 ` Oleksandr
2021-01-21 17:18 ` Rahul Singh
2021-01-21 18:31 ` Julien Grall
2021-01-21 18:50 ` Rahul Singh
2021-01-21 20:19 ` Julien Grall
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