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Date:      Sun, 3 Nov 2024 18:02:38 +0200
From:      Konstantin Belousov <kostikbel@gmail.com>
To:        Mark Johnston <markj@freebsd.org>
Cc:        src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org
Subject:   Re: git: 0f5116d7efe3 - main - AMD IOMMU driver
Message-ID:  <Zyeenp2GsurYlw04@kib.kiev.ua>
In-Reply-To: <ZyeZRlgfPKb78NA5@nuc>
References:  <202411022346.4A2NkeBT097606@gitrepo.freebsd.org> <ZyeZRlgfPKb78NA5@nuc>

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On Sun, Nov 03, 2024 at 10:39:50AM -0500, Mark Johnston wrote:
> On Sat, Nov 02, 2024 at 11:46:40PM +0000, Konstantin Belousov wrote:
> > The branch main has been updated by kib:
> > 
> > URL: https://cgit.FreeBSD.org/src/commit/?id=0f5116d7efe33c81f0b24b56eec78af37898f500
> > 
> > commit 0f5116d7efe33c81f0b24b56eec78af37898f500
> > Author:     Konstantin Belousov <kib@FreeBSD.org>
> > AuthorDate: 2024-05-12 10:20:11 +0000
> > Commit:     Konstantin Belousov <kib@FreeBSD.org>
> > CommitDate: 2024-11-02 23:45:40 +0000
> > 
> >     AMD IOMMU driver
> >     
> >     This driver is functionally equivalent to the in-tree Intel DMAR code.
> >     It handles busdma and interrupt remapping from the host OS.  There is no
> >     integration with bhyve, and the stub iommu drivers in bhyve code cannot
> >     coexist with this driver (planned).
> >     
> >     The biggest architectural problem with the code is that the AMD IOMMU
> >     units are enumerated as PCIe-attached security devices, which is much
> >     later after HPET and IOAPIC drivers attached and actived interrupts.
> >     Because of this, HPET FSB interrupts and IOAPIC interrupts are always
> >     identity-mapped.
> >     
> >     The code is of late alpha quality.  By default the driver is disabled.
> >     To enable for testing, set in loader.conf:
> >     hw.amdiommu.enable=1
> >     hw.iommu.dma=1 <- to enable iommu busdma
> >     hw.iommu.ir=1 <- to enable interrupt remapping
> >     
> >     Discussed with: emaste
> >     Sponsored by:   Advanced Micro Devices (AMD)
> >     Sponsored by:   The FreeBSD Foundation
> >     MFC after:      1 week
> >     Differential revision:  https://reviews.freebsd.org/D47256
> 
> This appears to break loading of vmm.ko, as sys/amd64/vmm/amd/amdiommu.c
> already defines a driver called "amdiommu".  Perhaps the module in vmm
> should be renamed to amdviiommu or so?
Perhaps.

Will you commit this yourself?



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