From: Jason Gunthorpe <jgg@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Cornelia Huck <cohuck@redhat.com>,
David Woodhouse <dwmw2@infradead.org>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
Kevin Tian <kevin.tian@intel.com>,
kvm@vger.kernel.org, linux-s390@vger.kernel.org,
Marc Zyngier <maz@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
Bharat Bhushan <bharat.bhushan@nxp.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Eric Auger <eric.auger@redhat.com>,
Eric Farman <farman@linux.ibm.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Matthew Rosato <mjrosato@linux.ibm.com>,
Tomasz Nowicki <tomasz.nowicki@caviumnetworks.com>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH iommufd 2/9] vfio/type1: Check that every device supports IOMMU_CAP_INTR_REMAP
Date: Thu, 8 Dec 2022 20:44:46 -0400 [thread overview]
Message-ID: <Y5KE/ikRGKnuaFAQ@nvidia.com> (raw)
In-Reply-To: <20221208144825.33823739.alex.williamson@redhat.com>
On Thu, Dec 08, 2022 at 02:48:25PM -0700, Alex Williamson wrote:
> On Thu, 8 Dec 2022 16:26:29 -0400
> Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> > iommu_group_for_each_dev() exits the loop at the first callback that
> > returns 1 - thus returning 1 fails to check the rest of the devices in the
> > group.
> >
> > msi_remap (aka secure MSI) requires that all the devices in the group
> > support it, not just any one. This is only a theoretical problem as no
> > current drivers will have different secure MSI properties within a group.
>
> Which is exactly how Robin justified the behavior in the referenced
> commit:
>
> As with domains, any capability must in practice be consistent for
> devices in a given group - and after all it's still the same
> capability which was expected to be consistent across an entire bus!
> - so there's no need for any complicated validation.
>
> That suggests to me that it's intentional that we break if any device
> supports the capability and therefore this isn't so much a "Fixes:", as
> it is a refactoring expressly to support msi_device_has_secure_msi(),
> which cannot make these sort of assumptions as a non-group API. Thanks,
Sure, lets drop the fixes and your analysis seems correct
Jason
next prev parent reply other threads:[~2022-12-09 0:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-08 20:26 [PATCH iommufd 0/9] Remove IOMMU_CAP_INTR_REMAP Jason Gunthorpe
2022-12-08 20:26 ` [PATCH iommufd 1/9] irq: Add msi_device_has_secure_msi() Jason Gunthorpe
2022-12-09 13:59 ` Marc Zyngier
2022-12-09 14:10 ` Jason Gunthorpe
2022-12-09 14:18 ` Marc Zyngier
2022-12-08 20:26 ` [PATCH iommufd 2/9] vfio/type1: Check that every device supports IOMMU_CAP_INTR_REMAP Jason Gunthorpe
2022-12-08 21:48 ` Alex Williamson
2022-12-09 0:44 ` Jason Gunthorpe [this message]
2022-12-09 10:24 ` Robin Murphy
2022-12-08 20:26 ` [PATCH iommufd 3/9] vfio/type1: Convert to msi_device_has_secure_msi() Jason Gunthorpe
2022-12-08 20:26 ` [PATCH iommufd 4/9] iommufd: " Jason Gunthorpe
2022-12-09 6:01 ` Tian, Kevin
2022-12-09 14:47 ` Jason Gunthorpe
2022-12-09 16:44 ` Robin Murphy
2022-12-09 17:38 ` Jason Gunthorpe
2022-12-12 15:17 ` Thomas Gleixner
2022-12-12 15:47 ` Jason Gunthorpe
2022-12-12 16:25 ` Thomas Gleixner
2022-12-08 20:26 ` [PATCH iommufd 5/9] irq: Remove unused irq_domain_check_msi_remap() code Jason Gunthorpe
2022-12-08 20:26 ` [PATCH iommufd 6/9] irq: Rename MSI_REMAP to SECURE_MSI Jason Gunthorpe
2022-12-08 20:26 ` [PATCH iommufd 7/9] iommu/x86: Replace IOMMU_CAP_INTR_REMAP with IRQ_DOMAIN_FLAG_SECURE_MSI Jason Gunthorpe
2022-12-08 20:26 ` [PATCH iommufd 8/9] irq/s390: Add arch_is_secure_msi() for s390 Jason Gunthorpe
2022-12-08 20:26 ` [PATCH iommufd 9/9] iommu: Remove IOMMU_CAP_INTR_REMAP Jason Gunthorpe
2022-12-08 23:37 ` [PATCH iommufd 0/9] " Matthew Rosato
2022-12-09 0:42 ` Jason Gunthorpe
2022-12-09 5:54 ` Tian, Kevin
2022-12-09 14:38 ` Jason Gunthorpe
2022-12-09 15:21 ` Jason Gunthorpe
2022-12-09 19:57 ` Thomas Gleixner
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