From: Joerg Roedel <joro@8bytes.org>
To: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>
Cc: "iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Joerg Roedel <jroedel@suse.de>, "bp@alien8.de" <bp@alien8.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3] iommu: Disable passthrough mode when SME is active
Date: Fri, 9 Aug 2019 22:32:08 +0200 [thread overview]
Message-ID: <20190809203208.GB1213@8bytes.org> (raw)
In-Reply-To: <7f383631-ce2c-e7c2-ceff-e7418bf8ff29@amd.com>
Hey Tom,
On Fri, Aug 09, 2019 at 04:50:48PM +0000, Lendacky, Thomas wrote:
> On 8/9/19 10:22 AM, Joerg Roedel wrote:
> > + if ((iommu_def_domain_type == IOMMU_DOMAIN_IDENTITY) &&
> > + sme_active()) {
> > + pr_info("SME detected - Disabling default IOMMU passthrough\n");
> > + iommu_def_domain_type = IOMMU_DOMAIN_DMA;
>
> Should this also clear the iommu_pass_through variable (the one set by the
> iommu kernel parameter in arch/x86/kernel/pci-dma.c)?
This code is used on different architectures, so I can't cleanly access
architecture specific variables here.
> I guess this is more applicable to the original patchset that created the
> CONFIG_IOMMU_DEFAULT_PASSTHROUGH option, but should the default
> passthrough support be modified so that you don't have to specify multiple
> kernel parameters to change it?
>
> Right now, if CONFIG_IOMMU_DEFAULT_PASSTHROUGH is set to yes, you can't
> just specify iommu=nopt to enable the IOMMU. You have to also specify
> iommu.passthrough=0. Do we want to fix that so that just specifying
> iommu=nopt or iommu.passthrough=0 does what is needed?
Yeah, that is currently a mess and I think cleaning that up is at least
partly in the scope of this patch-set. I'll look into that next week.
Regards,
Joerg
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prev parent reply other threads:[~2019-08-09 20:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 15:22 [PATCH 0/3] Disable IOMMU Passthrough when SME is active Joerg Roedel
2019-08-09 15:22 ` [PATCH 1/3] iommu: Print default domain type on boot Joerg Roedel
2019-08-09 15:22 ` [PATCH 2/3] iommu: Set default domain type at runtime Joerg Roedel
2019-08-09 15:22 ` [PATCH 3/3] iommu: Disable passthrough mode when SME is active Joerg Roedel
2019-08-09 16:50 ` Lendacky, Thomas
2019-08-09 20:32 ` Joerg Roedel [this message]
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