All of lore.kernel.org
 help / color / mirror / Atom feed
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

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>
Cc: "iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>,
	"bp@alien8.de" <bp@alien8.de>, Joerg Roedel <jroedel@suse.de>
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


  reply	other threads:[~2019-08-09 20:32 UTC|newest]

Thread overview: 12+ 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 ` Joerg Roedel
2019-08-09 15:22 ` [PATCH 1/3] iommu: Print default domain type on boot Joerg Roedel
2019-08-09 15:22   ` Joerg Roedel
2019-08-09 15:22 ` [PATCH 2/3] iommu: Set default domain type at runtime Joerg Roedel
2019-08-09 15:22   ` Joerg Roedel
2019-08-09 15:22 ` [PATCH 3/3] iommu: Disable passthrough mode when SME is active Joerg Roedel
2019-08-09 15:22   ` Joerg Roedel
2019-08-09 16:50   ` Lendacky, Thomas
2019-08-09 16:50     ` Lendacky, Thomas
2019-08-09 20:32     ` Joerg Roedel [this message]
2019-08-09 20:32       ` Joerg Roedel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190809203208.GB1213@8bytes.org \
    --to=joro@8bytes.org \
    --cc=Thomas.Lendacky@amd.com \
    --cc=bp@alien8.de \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jroedel@suse.de \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.