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
| ||
|
Message-ID: <468df11c-fe2a-2584-7306-185531653331@arm.com> Date: Tue, 23 Apr 2019 14:19:45 +0100 From: Robin Murphy <robin.murphy@....com> To: Marc Zyngier <marc.zyngier@....com>, Julien Grall <julien.grall@....com>, linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org Cc: logang@...tatee.com, douliyangs@...il.com, miquel.raynal@...tlin.com, jason@...edaemon.net, tglx@...utronix.de, joro@...tes.org, bigeasy@...utronix.de, linux-rt-users@...r.kernel.org Subject: Re: [PATCH 1/7] genirq/msi: Add a new field in msi_desc to store an IOMMU cookie On 23/04/2019 12:46, Marc Zyngier wrote: > On 23/04/2019 11:51, Julien Grall wrote: >> On 4/23/19 11:23 AM, Marc Zyngier wrote: >>> Hi Julien, >> >> Hi Marc, >> >>> On 18/04/2019 18:26, Julien Grall wrote: >>>> When an MSI doorbell is located downstream of an IOMMU, it is required >>>> to swizzle the physical address with an appropriately-mapped IOVA for any >>>> device attached to one of our DMA ops domain. >>>> >>>> At the moment, the allocation of the mapping may be done when composing >>>> the message. However, the composing may be done in non-preemtible >>>> context while the allocation requires to be called from preemptible >>>> context. >>>> >>>> A follow-up patch will split the current logic in two functions >>>> requiring to keep an IOMMU cookie per MSI. >>>> >>>> This patch introduces a new field in msi_desc to store an IOMMU cookie >>>> when CONFIG_IOMMU_DMA is selected. >>>> >>>> Signed-off-by: Julien Grall <julien.grall@....com> >>>> --- >>>> include/linux/msi.h | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/include/linux/msi.h b/include/linux/msi.h >>>> index 7e9b81c3b50d..d7907feef1bb 100644 >>>> --- a/include/linux/msi.h >>>> +++ b/include/linux/msi.h >>>> @@ -77,6 +77,9 @@ struct msi_desc { >>>> struct device *dev; >>>> struct msi_msg msg; >>>> struct irq_affinity_desc *affinity; >>>> +#ifdef CONFIG_IOMMU_DMA >>>> + const void *iommu_cookie; >>>> +#endif >>>> >>>> union { >>>> /* PCI MSI/X specific data */ >>>> >>> >>> Given that this is the only member in this structure that is dependent >>> on a config option, you could also add a couple of accessors that would >>> do nothing when IOMMU_DMA is not selected (and use that in the DMA code). >> >> I haven't seen any use of the helpers so far because the DMA code is >> also protected by IOMMU_DMA. >> >> I can add the helpers in the next version if you see any use outside of >> the DMA code. > > There may not be any user user yet, but I'd surely like to see the > accessors. This isn't very different from the stub functions you add in > patch #2. If you foresee this being useful in general, do you reckon it would be worth decoupling it under its own irqchip-layer Kconfig which can then be selected by IOMMU_DMA? Robin.
Powered by blists - more mailing lists