From: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To: Dongli Zhang <dongli.zhang@oracle.com>,
Christoph Hellwig <hch@lst.de>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>, Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Robin Murphy <robin.murphy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"tboot-devel@lists.sourceforge.net"
<tboot-devel@lists.sourceforge.net>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: RE: [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
Date: Sun, 6 Mar 2022 17:01:27 +0000 [thread overview]
Message-ID: <MN0PR21MB3098558B83B5A520FFCCE6D1D7079@MN0PR21MB3098.namprd21.prod.outlook.com> (raw)
In-Reply-To: <556312e4-da86-b980-475c-1cfd7818ffdc@oracle.com>
From: Dongli Zhang <dongli.zhang@oracle.com> Sent: Friday, March 4, 2022 10:28 AM
>
> Hi Michael,
>
> On 3/4/22 10:12 AM, Michael Kelley (LINUX) wrote:
> > From: Christoph Hellwig <hch@lst.de> Sent: Tuesday, March 1, 2022 2:53 AM
> >>
> >> Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for
> >> the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init
> >> interface by adding a new flag.
> >
> > Hyper-V Isolated VMs want to do the same thing of not restricting the swiotlb
> > buffer to low memory. That's what Tianyu Lan's patch set[1] is proposing.
> > Hyper-V synthetic devices have no DMA addressing limitations, and the
> > likelihood of using a PCI pass-thru device with addressing limitations in an
> > Isolated VM seems vanishingly small.
> >
> > So could use of the SWIOTLB_ANY flag be generalized? Let Hyper-V init
> > code set the flag before swiotlb_init() is called. Or provide a CONFIG
> > variable that Hyper-V Isolated VMs could set.
>
> I used to send 64-bit swiotlb, while at that time people thought it was the same
> as Restricted DMA patchset.
>
> https://lore.kernel.org/all/20210203233709.19819-1-dongli.zhang@oracle.com/
>
> However, I do not think Restricted DMA patchset is going to supports 64-bit (or
> high memory) DMA. Is this what you are looking for?
Yes, it looks like your patchset would do what we want for Hyper-V Isolated
VMs, but it is a more complex solution than is needed. My assertion is that
in some environments, such as Hyper-V Isolated VMs, we're willing to assume
all devices are 64-bit DMA capable, and to stop carrying the legacy baggage.
Bounce buffering is used for a different scenario (memory encryption), and
the bounce buffers can be allocated in high memory. There's no need for a
2nd swiotlb buffer.
Michael
WARNING: multiple messages have this Message-ID (diff)
From: "Michael Kelley \(LINUX\) via iommu" <iommu@lists.linux-foundation.org>
To: Dongli Zhang <dongli.zhang@oracle.com>,
Christoph Hellwig <hch@lst.de>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
Stefano Stabellini <sstabellini@kernel.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Robin Murphy <robin.murphy@arm.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"tboot-devel@lists.sourceforge.net"
<tboot-devel@lists.sourceforge.net>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
David Woodhouse <dwmw2@infradead.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
Date: Sun, 6 Mar 2022 17:01:27 +0000 [thread overview]
Message-ID: <MN0PR21MB3098558B83B5A520FFCCE6D1D7079@MN0PR21MB3098.namprd21.prod.outlook.com> (raw)
In-Reply-To: <556312e4-da86-b980-475c-1cfd7818ffdc@oracle.com>
From: Dongli Zhang <dongli.zhang@oracle.com> Sent: Friday, March 4, 2022 10:28 AM
>
> Hi Michael,
>
> On 3/4/22 10:12 AM, Michael Kelley (LINUX) wrote:
> > From: Christoph Hellwig <hch@lst.de> Sent: Tuesday, March 1, 2022 2:53 AM
> >>
> >> Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for
> >> the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init
> >> interface by adding a new flag.
> >
> > Hyper-V Isolated VMs want to do the same thing of not restricting the swiotlb
> > buffer to low memory. That's what Tianyu Lan's patch set[1] is proposing.
> > Hyper-V synthetic devices have no DMA addressing limitations, and the
> > likelihood of using a PCI pass-thru device with addressing limitations in an
> > Isolated VM seems vanishingly small.
> >
> > So could use of the SWIOTLB_ANY flag be generalized? Let Hyper-V init
> > code set the flag before swiotlb_init() is called. Or provide a CONFIG
> > variable that Hyper-V Isolated VMs could set.
>
> I used to send 64-bit swiotlb, while at that time people thought it was the same
> as Restricted DMA patchset.
>
> https://lore.kernel.org/all/20210203233709.19819-1-dongli.zhang@oracle.com/
>
> However, I do not think Restricted DMA patchset is going to supports 64-bit (or
> high memory) DMA. Is this what you are looking for?
Yes, it looks like your patchset would do what we want for Hyper-V Isolated
VMs, but it is a more complex solution than is needed. My assertion is that
in some environments, such as Hyper-V Isolated VMs, we're willing to assume
all devices are 64-bit DMA capable, and to stop carrying the legacy baggage.
Bounce buffering is used for a different scenario (memory encryption), and
the bounce buffers can be allocated in high memory. There's no need for a
2nd swiotlb buffer.
Michael
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To: Dongli Zhang <dongli.zhang@oracle.com>,
Christoph Hellwig <hch@lst.de>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
Stefano Stabellini <sstabellini@kernel.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>, "x86@kernel.org" <x86@kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"tboot-devel@lists.sourceforge.net"
<tboot-devel@lists.sourceforge.net>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
David Woodhouse <dwmw2@infradead.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>
Subject: RE: [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
Date: Sun, 6 Mar 2022 17:01:27 +0000 [thread overview]
Message-ID: <MN0PR21MB3098558B83B5A520FFCCE6D1D7079@MN0PR21MB3098.namprd21.prod.outlook.com> (raw)
In-Reply-To: <556312e4-da86-b980-475c-1cfd7818ffdc@oracle.com>
From: Dongli Zhang <dongli.zhang@oracle.com> Sent: Friday, March 4, 2022 10:28 AM
>
> Hi Michael,
>
> On 3/4/22 10:12 AM, Michael Kelley (LINUX) wrote:
> > From: Christoph Hellwig <hch@lst.de> Sent: Tuesday, March 1, 2022 2:53 AM
> >>
> >> Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for
> >> the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init
> >> interface by adding a new flag.
> >
> > Hyper-V Isolated VMs want to do the same thing of not restricting the swiotlb
> > buffer to low memory. That's what Tianyu Lan's patch set[1] is proposing.
> > Hyper-V synthetic devices have no DMA addressing limitations, and the
> > likelihood of using a PCI pass-thru device with addressing limitations in an
> > Isolated VM seems vanishingly small.
> >
> > So could use of the SWIOTLB_ANY flag be generalized? Let Hyper-V init
> > code set the flag before swiotlb_init() is called. Or provide a CONFIG
> > variable that Hyper-V Isolated VMs could set.
>
> I used to send 64-bit swiotlb, while at that time people thought it was the same
> as Restricted DMA patchset.
>
> https://lore.kernel.org/all/20210203233709.19819-1-dongli.zhang@oracle.com/
>
> However, I do not think Restricted DMA patchset is going to supports 64-bit (or
> high memory) DMA. Is this what you are looking for?
Yes, it looks like your patchset would do what we want for Hyper-V Isolated
VMs, but it is a more complex solution than is needed. My assertion is that
in some environments, such as Hyper-V Isolated VMs, we're willing to assume
all devices are 64-bit DMA capable, and to stop carrying the legacy baggage.
Bounce buffering is used for a different scenario (memory encryption), and
the bounce buffers can be allocated in high memory. There's no need for a
2nd swiotlb buffer.
Michael
WARNING: multiple messages have this Message-ID (diff)
From: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To: Dongli Zhang <dongli.zhang@oracle.com>,
Christoph Hellwig <hch@lst.de>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>, Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Robin Murphy <robin.murphy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"tboot-devel@lists.sourceforge.net"
<tboot-devel@lists.sourceforge.net>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: RE: [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
Date: Sun, 6 Mar 2022 17:01:27 +0000 [thread overview]
Message-ID: <MN0PR21MB3098558B83B5A520FFCCE6D1D7079@MN0PR21MB3098.namprd21.prod.outlook.com> (raw)
In-Reply-To: <556312e4-da86-b980-475c-1cfd7818ffdc@oracle.com>
From: Dongli Zhang <dongli.zhang@oracle.com> Sent: Friday, March 4, 2022 10:28 AM
>
> Hi Michael,
>
> On 3/4/22 10:12 AM, Michael Kelley (LINUX) wrote:
> > From: Christoph Hellwig <hch@lst.de> Sent: Tuesday, March 1, 2022 2:53 AM
> >>
> >> Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for
> >> the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init
> >> interface by adding a new flag.
> >
> > Hyper-V Isolated VMs want to do the same thing of not restricting the swiotlb
> > buffer to low memory. That's what Tianyu Lan's patch set[1] is proposing.
> > Hyper-V synthetic devices have no DMA addressing limitations, and the
> > likelihood of using a PCI pass-thru device with addressing limitations in an
> > Isolated VM seems vanishingly small.
> >
> > So could use of the SWIOTLB_ANY flag be generalized? Let Hyper-V init
> > code set the flag before swiotlb_init() is called. Or provide a CONFIG
> > variable that Hyper-V Isolated VMs could set.
>
> I used to send 64-bit swiotlb, while at that time people thought it was the same
> as Restricted DMA patchset.
>
> https://lore.kernel.org/all/20210203233709.19819-1-dongli.zhang@oracle.com/
>
> However, I do not think Restricted DMA patchset is going to supports 64-bit (or
> high memory) DMA. Is this what you are looking for?
Yes, it looks like your patchset would do what we want for Hyper-V Isolated
VMs, but it is a more complex solution than is needed. My assertion is that
in some environments, such as Hyper-V Isolated VMs, we're willing to assume
all devices are 64-bit DMA capable, and to stop carrying the legacy baggage.
Bounce buffering is used for a different scenario (memory encryption), and
the bounce buffers can be allocated in high memory. There's no need for a
2nd swiotlb buffer.
Michael
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
WARNING: multiple messages have this Message-ID (diff)
From: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To: Dongli Zhang <dongli.zhang@oracle.com>,
Christoph Hellwig <hch@lst.de>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>, Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Robin Murphy <robin.murphy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"tboot-devel@lists.sourceforge.net"
<tboot-devel@lists.sourceforge.net>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: RE: [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
Date: Sun, 6 Mar 2022 17:01:27 +0000 [thread overview]
Message-ID: <MN0PR21MB3098558B83B5A520FFCCE6D1D7079@MN0PR21MB3098.namprd21.prod.outlook.com> (raw)
In-Reply-To: <556312e4-da86-b980-475c-1cfd7818ffdc@oracle.com>
From: Dongli Zhang <dongli.zhang@oracle.com> Sent: Friday, March 4, 2022 10:28 AM
>
> Hi Michael,
>
> On 3/4/22 10:12 AM, Michael Kelley (LINUX) wrote:
> > From: Christoph Hellwig <hch@lst.de> Sent: Tuesday, March 1, 2022 2:53 AM
> >>
> >> Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for
> >> the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init
> >> interface by adding a new flag.
> >
> > Hyper-V Isolated VMs want to do the same thing of not restricting the swiotlb
> > buffer to low memory. That's what Tianyu Lan's patch set[1] is proposing.
> > Hyper-V synthetic devices have no DMA addressing limitations, and the
> > likelihood of using a PCI pass-thru device with addressing limitations in an
> > Isolated VM seems vanishingly small.
> >
> > So could use of the SWIOTLB_ANY flag be generalized? Let Hyper-V init
> > code set the flag before swiotlb_init() is called. Or provide a CONFIG
> > variable that Hyper-V Isolated VMs could set.
>
> I used to send 64-bit swiotlb, while at that time people thought it was the same
> as Restricted DMA patchset.
>
> https://lore.kernel.org/all/20210203233709.19819-1-dongli.zhang@oracle.com/
>
> However, I do not think Restricted DMA patchset is going to supports 64-bit (or
> high memory) DMA. Is this what you are looking for?
Yes, it looks like your patchset would do what we want for Hyper-V Isolated
VMs, but it is a more complex solution than is needed. My assertion is that
in some environments, such as Hyper-V Isolated VMs, we're willing to assume
all devices are 64-bit DMA capable, and to stop carrying the legacy baggage.
Bounce buffering is used for a different scenario (memory encryption), and
the bounce buffers can be allocated in high memory. There's no need for a
2nd swiotlb buffer.
Michael
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To: Dongli Zhang <dongli.zhang@oracle.com>,
Christoph Hellwig <hch@lst.de>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>, Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Robin Murphy <robin.murphy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"tboot-devel@lists.sourceforge.net"
<tboot-devel@lists.sourceforge.net>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: RE: [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
Date: Sun, 06 Mar 2022 17:01:27 +0000 [thread overview]
Message-ID: <MN0PR21MB3098558B83B5A520FFCCE6D1D7079@MN0PR21MB3098.namprd21.prod.outlook.com> (raw)
In-Reply-To: <556312e4-da86-b980-475c-1cfd7818ffdc@oracle.com>
From: Dongli Zhang <dongli.zhang@oracle.com> Sent: Friday, March 4, 2022 10:28 AM
>
> Hi Michael,
>
> On 3/4/22 10:12 AM, Michael Kelley (LINUX) wrote:
> > From: Christoph Hellwig <hch@lst.de> Sent: Tuesday, March 1, 2022 2:53 AM
> >>
> >> Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for
> >> the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init
> >> interface by adding a new flag.
> >
> > Hyper-V Isolated VMs want to do the same thing of not restricting the swiotlb
> > buffer to low memory. That's what Tianyu Lan's patch set[1] is proposing.
> > Hyper-V synthetic devices have no DMA addressing limitations, and the
> > likelihood of using a PCI pass-thru device with addressing limitations in an
> > Isolated VM seems vanishingly small.
> >
> > So could use of the SWIOTLB_ANY flag be generalized? Let Hyper-V init
> > code set the flag before swiotlb_init() is called. Or provide a CONFIG
> > variable that Hyper-V Isolated VMs could set.
>
> I used to send 64-bit swiotlb, while at that time people thought it was the same
> as Restricted DMA patchset.
>
> https://lore.kernel.org/all/20210203233709.19819-1-dongli.zhang@oracle.com/
>
> However, I do not think Restricted DMA patchset is going to supports 64-bit (or
> high memory) DMA. Is this what you are looking for?
Yes, it looks like your patchset would do what we want for Hyper-V Isolated
VMs, but it is a more complex solution than is needed. My assertion is that
in some environments, such as Hyper-V Isolated VMs, we're willing to assume
all devices are 64-bit DMA capable, and to stop carrying the legacy baggage.
Bounce buffering is used for a different scenario (memory encryption), and
the bounce buffers can be allocated in high memory. There's no need for a
2nd swiotlb buffer.
Michael
next prev parent reply other threads:[~2022-03-06 17:01 UTC|newest]
Thread overview: 228+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-01 10:52 cleanup swiotlb initialization v4 Christoph Hellwig
2022-03-01 10:52 ` Christoph Hellwig
2022-03-01 10:52 ` Christoph Hellwig
2022-03-01 10:52 ` Christoph Hellwig
2022-03-01 10:52 ` Christoph Hellwig
2022-03-01 10:52 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 01/12] dma-direct: use is_swiotlb_active in dma_direct_map_page Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 02/12] swiotlb: make swiotlb_exit a no-op if SWIOTLB_FORCE is set Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 03/12] swiotlb: simplify swiotlb_max_segment Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 04/12] swiotlb: rename swiotlb_late_init_with_default_size Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 05/12] swiotlb: pass a gfp_mask argument to swiotlb_init_late Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 06/12] MIPS/octeon: use swiotlb_init instead of open coding it Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-03 16:39 ` Thomas Bogendoerfer
2022-03-03 16:39 ` Thomas Bogendoerfer
2022-03-03 16:39 ` Thomas Bogendoerfer
2022-03-03 16:39 ` Thomas Bogendoerfer
2022-03-03 16:39 ` Thomas Bogendoerfer
2022-03-03 16:39 ` Thomas Bogendoerfer
2022-03-01 10:53 ` [PATCH 07/12] x86: remove the IOMMU table infrastructure Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 08/12] x86: centralize setting SWIOTLB_FORCE when guest memory encryption is enabled Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 11:39 ` Andrew Cooper
2022-03-01 11:39 ` Andrew Cooper
2022-03-01 11:39 ` Andrew Cooper via iommu
2022-03-01 11:39 ` Andrew Cooper
2022-03-01 11:39 ` Andrew Cooper
2022-03-01 11:39 ` Andrew Cooper
2022-03-01 11:43 ` Christoph Hellwig
2022-03-01 11:43 ` Christoph Hellwig
2022-03-01 11:43 ` Christoph Hellwig
2022-03-01 11:43 ` Christoph Hellwig
2022-03-01 11:43 ` Christoph Hellwig
2022-03-01 11:43 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 09/12] swiotlb: make the swiotlb_init interface more useful Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` [PATCH 10/12] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-04 18:12 ` Michael Kelley (LINUX)
2022-03-04 18:12 ` Michael Kelley (LINUX)
2022-03-04 18:12 ` Michael Kelley (LINUX)
2022-03-04 18:12 ` Michael Kelley (LINUX)
2022-03-04 18:12 ` Michael Kelley (LINUX)
2022-03-04 18:12 ` Michael Kelley (LINUX) via iommu
2022-03-04 18:27 ` Dongli Zhang
2022-03-04 18:27 ` Dongli Zhang
2022-03-04 18:27 ` Dongli Zhang
2022-03-04 18:27 ` Dongli Zhang
2022-03-04 18:27 ` Dongli Zhang
2022-03-04 18:27 ` Dongli Zhang
2022-03-06 17:01 ` Michael Kelley (LINUX) [this message]
2022-03-06 17:01 ` Michael Kelley (LINUX)
2022-03-06 17:01 ` Michael Kelley (LINUX)
2022-03-06 17:01 ` Michael Kelley (LINUX)
2022-03-06 17:01 ` Michael Kelley (LINUX)
2022-03-06 17:01 ` Michael Kelley (LINUX) via iommu
2022-03-01 10:53 ` [PATCH 11/12] swiotlb: merge swiotlb-xen initialization into swiotlb Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-02 2:55 ` Stefano Stabellini
2022-03-02 2:55 ` Stefano Stabellini
2022-03-02 2:55 ` Stefano Stabellini
2022-03-02 2:55 ` Stefano Stabellini
2022-03-02 2:55 ` Stefano Stabellini
2022-03-02 2:55 ` Stefano Stabellini
2022-03-02 8:15 ` Christoph Hellwig
2022-03-02 8:15 ` Christoph Hellwig
2022-03-02 8:15 ` Christoph Hellwig
2022-03-02 8:15 ` Christoph Hellwig
2022-03-02 8:15 ` Christoph Hellwig
2022-03-02 8:15 ` Christoph Hellwig
2022-03-03 1:25 ` Stefano Stabellini
2022-03-03 1:25 ` Stefano Stabellini
2022-03-03 1:25 ` Stefano Stabellini
2022-03-03 1:25 ` Stefano Stabellini
2022-03-03 1:25 ` Stefano Stabellini
2022-03-03 1:25 ` Stefano Stabellini
2022-03-03 10:59 ` Christoph Hellwig
2022-03-03 10:59 ` Christoph Hellwig
2022-03-03 10:59 ` Christoph Hellwig
2022-03-03 10:59 ` Christoph Hellwig
2022-03-03 10:59 ` Christoph Hellwig
2022-03-03 10:59 ` Christoph Hellwig
2022-03-03 22:49 ` Stefano Stabellini
2022-03-03 22:49 ` Stefano Stabellini
2022-03-03 22:49 ` Stefano Stabellini
2022-03-03 22:49 ` Stefano Stabellini
2022-03-03 22:49 ` Stefano Stabellini
2022-03-03 22:49 ` Stefano Stabellini
2022-03-04 16:34 ` Christoph Hellwig
2022-03-04 16:34 ` Christoph Hellwig
2022-03-04 16:34 ` Christoph Hellwig
2022-03-04 16:34 ` Christoph Hellwig
2022-03-04 16:34 ` Christoph Hellwig
2022-03-04 16:34 ` Christoph Hellwig
2022-03-04 23:22 ` Stefano Stabellini
2022-03-04 23:22 ` Stefano Stabellini
2022-03-04 23:22 ` Stefano Stabellini
2022-03-04 23:22 ` Stefano Stabellini
2022-03-04 23:22 ` Stefano Stabellini
2022-03-04 23:22 ` Stefano Stabellini
2022-03-02 13:15 ` Boris Ostrovsky
2022-03-02 13:15 ` Boris Ostrovsky
2022-03-02 13:15 ` Boris Ostrovsky
2022-03-02 13:15 ` Boris Ostrovsky
2022-03-02 13:15 ` Boris Ostrovsky
2022-03-02 13:15 ` Boris Ostrovsky
2022-03-02 13:17 ` Boris Ostrovsky
2022-03-02 13:17 ` Boris Ostrovsky
2022-03-02 13:17 ` Boris Ostrovsky
2022-03-02 13:17 ` Boris Ostrovsky
2022-03-02 13:17 ` Boris Ostrovsky
2022-03-02 13:17 ` Boris Ostrovsky
2022-03-03 10:57 ` Christoph Hellwig
2022-03-03 10:57 ` Christoph Hellwig
2022-03-03 10:57 ` Christoph Hellwig
2022-03-03 10:57 ` Christoph Hellwig
2022-03-03 10:57 ` Christoph Hellwig
2022-03-03 10:57 ` Christoph Hellwig
2022-03-03 19:06 ` Boris Ostrovsky
2022-03-03 19:06 ` Boris Ostrovsky
2022-03-03 19:06 ` Boris Ostrovsky
2022-03-03 19:06 ` Boris Ostrovsky
2022-03-03 19:06 ` Boris Ostrovsky
2022-03-03 19:06 ` Boris Ostrovsky
2022-03-04 17:28 ` Christoph Hellwig
2022-03-04 17:28 ` Christoph Hellwig
2022-03-04 17:28 ` Christoph Hellwig
2022-03-04 17:28 ` Christoph Hellwig
2022-03-04 17:28 ` Christoph Hellwig
2022-03-04 17:28 ` Christoph Hellwig
2022-03-04 17:36 ` Boris Ostrovsky
2022-03-04 17:36 ` Boris Ostrovsky
2022-03-04 17:36 ` Boris Ostrovsky
2022-03-04 17:36 ` Boris Ostrovsky
2022-03-04 17:36 ` Boris Ostrovsky
2022-03-04 17:36 ` Boris Ostrovsky
2022-03-04 17:43 ` Christoph Hellwig
2022-03-04 17:43 ` Christoph Hellwig
2022-03-04 17:43 ` Christoph Hellwig
2022-03-04 17:43 ` Christoph Hellwig
2022-03-04 17:43 ` Christoph Hellwig
2022-03-04 17:43 ` Christoph Hellwig
2022-03-04 20:18 ` Boris Ostrovsky
2022-03-04 20:18 ` Boris Ostrovsky
2022-03-04 20:18 ` Boris Ostrovsky
2022-03-04 20:18 ` Boris Ostrovsky
2022-03-04 20:18 ` Boris Ostrovsky
2022-03-04 20:18 ` Boris Ostrovsky
2022-03-04 21:03 ` Christoph Hellwig
2022-03-04 21:03 ` Christoph Hellwig
2022-03-04 21:03 ` Christoph Hellwig
2022-03-04 21:03 ` Christoph Hellwig
2022-03-04 21:03 ` Christoph Hellwig
2022-03-04 21:03 ` Christoph Hellwig
2022-03-08 21:38 ` Boris Ostrovsky
2022-03-08 21:38 ` Boris Ostrovsky
2022-03-08 21:38 ` Boris Ostrovsky
2022-03-08 21:38 ` Boris Ostrovsky
2022-03-08 21:38 ` Boris Ostrovsky
2022-03-08 21:38 ` Boris Ostrovsky
2022-03-09 6:18 ` Christoph Hellwig
2022-03-09 6:18 ` Christoph Hellwig
2022-03-09 6:18 ` Christoph Hellwig
2022-03-09 6:18 ` Christoph Hellwig
2022-03-09 6:18 ` Christoph Hellwig
2022-03-09 6:18 ` Christoph Hellwig
2022-03-09 15:18 ` Boris Ostrovsky
2022-03-09 15:18 ` Boris Ostrovsky
2022-03-09 15:18 ` Boris Ostrovsky
2022-03-09 15:18 ` Boris Ostrovsky
2022-03-09 15:18 ` Boris Ostrovsky
2022-03-09 15:18 ` Boris Ostrovsky
2022-03-01 10:53 ` [PATCH 12/12] x86: remove cruft from <asm/dma-mapping.h> Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
2022-03-01 10:53 ` Christoph Hellwig
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