From: Jason Gunthorpe <jgg@nvidia.com>
To: Andrew Jones <andrew.jones@oss.qualcomm.com>
Cc: linux-riscv@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, tomasz.jeznach@linux.dev,
tjeznach@rivosinc.com, joro@8bytes.org, will@kernel.org,
robin.murphy@arm.com, pjw@kernel.org, palmer@dabbelt.com,
anup@brainfault.org, tglx@kernel.org, kevin.tian@intel.com,
fangyu.yu@linux.alibaba.com
Subject: Re: [PATCH v4 02/21] iommufd: Add iommufd_sw_map_msi()
Date: Thu, 27 Aug 2026 09:11:05 -0300 [thread overview]
Message-ID: <20260827121105.GQ3325090@nvidia.com> (raw)
In-Reply-To: <lxrej2bonrvt5ew7e6wjupcaptj7nxpesnzwvktjusawg3od2u@v3zb2bdjdilo>
On Thu, Aug 27, 2026 at 10:47:47AM +0200, Andrew Jones wrote:
> I think it should be possible to follow AMD's model more closely. I'll
> create one IOMMU-owned irqdomain and install it as each device's MSI
> parent at probe time, provided the device currently uses the expected
> IMSIC MSI domain, which will be the IOMMU irqdomain's parent. The
> irqdomain will contain no per-device or MSI-table state and its callbacks
> can recover the device and operate on its currently attached S2 domain.
> This is better than the per-device irqdomain since sharing it avoids
> redundant domains.
I would still like to go over this with Thomas. It does feel more
logical to me that there would be one irqdomain per MSI table.
I dislike this implicit weak coupling between the iommufd viommu
operating the S2 and representing the VM and the irqdomain then
"magically" discovering what VM it is part of and what MSI table the
device is supposed to us.
I also don't want the iommu side to be managing msi tables. It would
be more reasonable for the generic viommu world to create irqdomains
per-VM...
Jason
next prev parent reply other threads:[~2026-08-27 12:11 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-20 21:41 [PATCH v4 00/21] iommu/riscv: Enable MSI remapping, IOMMU_DMA and VFIO Andrew Jones
2026-08-20 21:41 ` [PATCH v4 01/21] iommufd: Convert struct iommufd_sw_msi_maps to a growable bitmap Andrew Jones
2026-08-20 21:41 ` [PATCH v4 02/21] iommufd: Add iommufd_sw_map_msi() Andrew Jones
2026-08-20 22:09 ` Jason Gunthorpe
2026-08-21 11:07 ` Andrew Jones
2026-08-21 12:02 ` Jason Gunthorpe
2026-08-21 13:47 ` Andrew Jones
2026-08-21 14:00 ` Jason Gunthorpe
2026-08-21 14:23 ` Andrew Jones
2026-08-21 14:31 ` Jason Gunthorpe
2026-08-21 15:18 ` Andrew Jones
2026-08-21 16:12 ` Jason Gunthorpe
2026-08-21 17:12 ` Andrew Jones
2026-08-21 17:20 ` Jason Gunthorpe
2026-08-22 13:50 ` Andrew Jones
2026-08-22 14:06 ` Jason Gunthorpe
2026-08-24 8:50 ` Andrew Jones
2026-08-24 12:52 ` Jason Gunthorpe
2026-08-24 15:43 ` Andrew Jones
2026-08-24 17:04 ` Jason Gunthorpe
2026-08-25 13:24 ` Andrew Jones
2026-08-25 14:03 ` Jason Gunthorpe
2026-08-25 16:14 ` Andrew Jones
2026-08-25 16:52 ` Jason Gunthorpe
2026-08-25 17:38 ` Andrew Jones
2026-08-25 17:59 ` Jason Gunthorpe
2026-08-26 8:23 ` Andrew Jones
2026-08-26 14:48 ` Andrew Jones
2026-08-26 16:32 ` Jason Gunthorpe
2026-08-26 18:11 ` Andrew Jones
2026-08-27 8:47 ` Andrew Jones
2026-08-27 12:11 ` Jason Gunthorpe [this message]
2026-08-20 21:41 ` [PATCH v4 03/21] iommu/dma: Add iommu_dma_sw_map_msi() Andrew Jones
2026-08-20 21:41 ` [PATCH v4 04/21] iommu/dma: Add iommu_dma_map_msi() Andrew Jones
2026-08-20 21:41 ` [PATCH v4 05/21] iommu: Document MSI mapping during domain replacement Andrew Jones
2026-08-20 21:41 ` [PATCH v4 06/21] genirq/msi: Provide DOMAIN_BUS_MSI_REMAP Andrew Jones
2026-08-20 21:41 ` [PATCH v4 07/21] irqchip/riscv-imsic: Compose MSI updates through the hierarchy Andrew Jones
2026-08-20 21:41 ` [PATCH v4 08/21] iommu/riscv: Add IRQ domain for interrupt remapping Andrew Jones
2026-08-20 21:41 ` [PATCH v4 09/21] iommu/riscv: Refresh platform MSI domain before IR setup Andrew Jones
2026-08-20 21:41 ` [PATCH v4 10/21] iommu/riscv: Prepare info->domain for concurrent RCU read access Andrew Jones
2026-08-20 21:41 ` [PATCH v4 11/21] iommu/riscv: Reserve an MSI IOVA window for iommufd Andrew Jones
2026-08-20 21:41 ` [PATCH v4 12/21] iommu/riscv: Pre-map IMSIC MSI targets Andrew Jones
2026-08-20 21:41 ` [PATCH v4 13/21] iommu/riscv: Preserve MSI IOVA state across domain replacement Andrew Jones
2026-08-20 21:52 ` Jason Gunthorpe
2026-08-21 11:14 ` Andrew Jones
2026-08-21 13:22 ` Jason Gunthorpe
2026-08-21 13:56 ` Andrew Jones
2026-08-20 21:41 ` [PATCH v4 14/21] iommu/riscv: Gate direct identity boundary switches with live MSIs Andrew Jones
2026-08-20 21:41 ` [PATCH v4 15/21] iommu/riscv: Remap IMSIC targets during MSI composition Andrew Jones
2026-08-20 21:41 ` [PATCH v4 16/21] iommu/dma: Enable IOMMU_DMA for 64-bit RISC-V Andrew Jones
2026-08-20 21:41 ` [PATCH v4 17/21] iommu/riscv: Report cache coherency capability Andrew Jones
2026-08-20 21:47 ` Jason Gunthorpe
2026-08-21 11:15 ` Andrew Jones
2026-08-20 21:41 ` [PATCH v4 18/21] vfio: enable IOMMU_TYPE1 for RISC-V Andrew Jones
2026-08-20 21:41 ` [PATCH v4 19/21] RISC-V: KVM: Enable KVM_VFIO interfaces on RISC-V arch Andrew Jones
2026-08-20 21:41 ` [PATCH v4 20/21] riscv: defconfig: Enable IOMMUFD and VFIO Andrew Jones
2026-08-20 21:41 ` [PATCH v4 21/21] selftests/vfio: Allow building on RISC-V Andrew Jones
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