From: Jason Gunthorpe <jgg@ziepe.ca>
To: Demi Marie Obenour <demiobenour@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"Jason Wang" <jasowang@redhat.com>,
"Xuan Zhuo" <xuanzhuo@linux.alibaba.com>,
"Eugenio Pérez" <eperezma@redhat.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Len Brown" <lenb@kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Joerg Roedel" <joro@8bytes.org>, "Will Deacon" <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Alyssa Ross" <hi@alyssa.is>,
virtualization@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-acpi@vger.kernel.org, iommu@lists.linux.dev,
x86@kernel.org, "Spectrum OS Development" <devel@spectrum-os.org>
Subject: Re: Virtio-IOMMU interrupt remapping design
Date: Mon, 16 Jun 2025 10:20:31 -0300 [thread overview]
Message-ID: <20250616132031.GB1354058@ziepe.ca> (raw)
In-Reply-To: <a65d955c-192b-4e79-ab11-8e2af78b62af@gmail.com>
On Sun, Jun 15, 2025 at 02:47:15PM -0400, Demi Marie Obenour wrote:
> Is a paravirtualized IOMMU with interrupt remapping something that makes
> sense?
IMHO linking interrupt remapping to the iommu is a poor design,
interrupt routing belongs in the irq subsystem, not in the iommu.
The fact AMD and Intel both coupled their interrupt routing to their
iommu hardware is just a weird design decision. ARM didn't do this,
for instance.
So I would not try to do this at all, you should have a
para-virtualized IRQ interface, not an extension to virtio-iommu
adding interrupt handling. :\
AFAIK hyperv shows how to build something like this.
Jason
next prev parent reply other threads:[~2025-06-16 13:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-15 18:47 Virtio-IOMMU interrupt remapping design Demi Marie Obenour
2025-06-16 13:20 ` Jason Gunthorpe [this message]
2025-06-16 16:53 ` Demi Marie Obenour
2025-06-16 17:33 ` Jason Gunthorpe
2025-06-17 19:44 ` Michael S. Tsirkin
2025-06-17 19:57 ` Jason Gunthorpe
2025-06-17 20:01 ` Michael S. Tsirkin
2025-06-17 23:03 ` Jason Gunthorpe
2025-06-17 19:46 ` Michael S. Tsirkin
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