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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alexander Graf <agraf@suse.de>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
	kvm@vger.kernel.org
Subject: Re: [PATCH 12/13] kvm/powerpc: Accelerate H_PUT_TCE by implementing it in real mode
Date: Tue, 17 May 2011 19:11:50 +1000	[thread overview]
Message-ID: <1305623510.2781.20.camel@pasglop> (raw)
In-Reply-To: <E9A07C6B-00BC-490F-95E7-5B025A626C98@suse.de>

On Tue, 2011-05-17 at 10:01 +0200, Alexander Graf wrote:
> I'm not sure I fully understand how this is supposed to work. If the
> tables are kept inside the kernel, how does userspace get to know
> where to DMA to?

The guest gets a dma range from the device-tree which is the range of
device-side dma addresses it can use that correspond to the table.

The guest kernel uses the normal linux iommu space allocator to allocate
space in that region and uses H_PUT_TCE to populate the corresponding
table entries.

This is the same interface that is used for "real" iommu's with PCI
devices btw.

Cheers,
Ben.

WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>,
	linuxppc-dev@ozlabs.org, kvm@vger.kernel.org
Subject: Re: [PATCH 12/13] kvm/powerpc: Accelerate H_PUT_TCE by implementing it in real mode
Date: Tue, 17 May 2011 19:11:50 +1000	[thread overview]
Message-ID: <1305623510.2781.20.camel@pasglop> (raw)
In-Reply-To: <E9A07C6B-00BC-490F-95E7-5B025A626C98@suse.de>

On Tue, 2011-05-17 at 10:01 +0200, Alexander Graf wrote:
> I'm not sure I fully understand how this is supposed to work. If the
> tables are kept inside the kernel, how does userspace get to know
> where to DMA to?

The guest gets a dma range from the device-tree which is the range of
device-side dma addresses it can use that correspond to the table.

The guest kernel uses the normal linux iommu space allocator to allocate
space in that region and uses H_PUT_TCE to populate the corresponding
table entries.

This is the same interface that is used for "real" iommu's with PCI
devices btw.

Cheers,
Ben.



  reply	other threads:[~2011-05-17  9:11 UTC|newest]

Thread overview: 103+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-11 10:34 [PATCH 0/13] Hypervisor-mode KVM on POWER7 Paul Mackerras
2011-05-11 10:36 ` [PATCH 01/13] kvm/powerpc: Move fields between struct kvm_vcpu_arch and kvmppc_vcpu_book3s Paul Mackerras
2011-05-11 10:38 ` [PATCH 02/13] kvm/powerpc: Fix kvmppc_core_pending_dec Paul Mackerras
2011-05-11 10:39 ` [PATCH 03/13] kvm/powerpc: Fix the build for 32-bit Book 3S (classic) processors Paul Mackerras
2011-05-12  9:33   ` Alexander Graf
2011-05-12  9:33     ` Alexander Graf
2011-05-12 11:15     ` Paul Mackerras
2011-05-12 11:15       ` Paul Mackerras
2011-05-12 11:16     ` Benjamin Herrenschmidt
2011-05-12 11:16       ` Benjamin Herrenschmidt
2011-05-12 11:57       ` Alexander Graf
2011-05-12 11:57         ` Alexander Graf
2011-05-11 10:40 ` [PATCH 04/13] kvm/powerpc: Split out code from book3s.c into book3s_pr.c Paul Mackerras
2011-05-11 10:41 ` [PATCH 05/13] powerpc, kvm: Rework KVM checks in first-level interrupt handlers Paul Mackerras
2011-05-11 10:42 ` [PATCH 06/13] kvm/powerpc: Deliver program interrupts right away instead of queueing them Paul Mackerras
2011-05-11 10:42 ` [PATCH 07/13] kvm/powerpc: Pass init/destroy vm and prepare/commit memory region ops down Paul Mackerras
2011-05-11 10:43 ` [PATCH 08/13] kvm/powerpc: Move guest enter/exit down into subarch-specific code Paul Mackerras
2011-05-17 18:05   ` Marcelo Tosatti
2011-05-17 18:05     ` Marcelo Tosatti
2011-05-17 18:10     ` Marcelo Tosatti
2011-05-17 18:10       ` Marcelo Tosatti
2011-05-11 10:44 ` [PATCH 09/13] powerpc: Set up LPCR for running guest partitions Paul Mackerras
2011-05-11 10:44 ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in hypervisor mode Paul Mackerras
2011-05-12  9:07   ` Avi Kivity
2011-05-12  9:07     ` Avi Kivity
2011-05-16  1:07     ` Paul Mackerras
2011-05-16  1:07       ` Paul Mackerras
2011-05-15 21:58   ` Alexander Graf
2011-05-15 21:58     ` Alexander Graf
2011-05-15 21:58     ` Alexander Graf
2011-05-16  5:58     ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in Paul Mackerras
2011-05-16  5:58       ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in hypervisor mode Paul Mackerras
2011-05-16  5:58       ` Paul Mackerras
2011-05-17 10:17       ` Alexander Graf
2011-05-17 10:17         ` Alexander Graf
2011-05-17 10:17         ` Alexander Graf
2011-05-27 10:33         ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in Paul Mackerras
2011-05-27 10:33           ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in hypervisor mode Paul Mackerras
2011-05-27 10:33           ` Paul Mackerras
2011-05-27 10:43           ` Alexander Graf
2011-05-27 10:43             ` Alexander Graf
2011-05-27 10:43             ` Alexander Graf
2011-05-27 20:59           ` Segher Boessenkool
2011-05-27 20:59             ` Segher Boessenkool
2011-05-27 20:59             ` Segher Boessenkool
2011-05-27 23:19             ` Alexander Graf
2011-05-27 23:19               ` Alexander Graf
2011-05-27 23:19               ` Alexander Graf
2011-05-28  1:07               ` Segher Boessenkool
2011-05-28  1:07                 ` Segher Boessenkool
2011-05-28  1:07                 ` Segher Boessenkool
2011-05-31 20:26                 ` Jimi Xenidis
2011-05-31 20:26                   ` Jimi Xenidis
2011-05-31 20:26                   ` Jimi Xenidis
2011-05-31 22:34                   ` Segher Boessenkool
2011-05-31 22:34                     ` Segher Boessenkool
2011-05-31 22:34                     ` Segher Boessenkool
2011-06-01  5:11                     ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in Paul Mackerras
2011-06-01  5:11                       ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in hypervisor mode Paul Mackerras
2011-06-01  5:11                       ` Paul Mackerras
2011-05-11 10:45 ` [PATCH 11/13] kvm/powerpc: Handle some PAPR hcalls in the kernel Paul Mackerras
2011-05-17  7:54   ` Alexander Graf
2011-05-17  7:54     ` Alexander Graf
2011-05-17 10:28     ` Paul Mackerras
2011-05-11 10:46 ` [PATCH 12/13] kvm/powerpc: Accelerate H_PUT_TCE by implementing it in real mode Paul Mackerras
2011-05-17  8:01   ` Alexander Graf
2011-05-17  8:01     ` Alexander Graf
2011-05-17  9:11     ` Benjamin Herrenschmidt [this message]
2011-05-17  9:11       ` Benjamin Herrenschmidt
2011-05-17  9:31       ` Alexander Graf
2011-05-17  9:31         ` Alexander Graf
2011-05-17  9:35         ` Benjamin Herrenschmidt
2011-05-17  9:35           ` Benjamin Herrenschmidt
2011-05-17  9:39           ` Alexander Graf
2011-05-17  9:39             ` Alexander Graf
2011-05-11 10:46 ` [PATCH 13/13] kvm/powerpc: Allow book3s_hv guests to use SMT processor modes Paul Mackerras
2011-05-11 13:44   ` Christoph Hellwig
2011-05-11 21:17     ` Paul Mackerras
2011-05-11 21:17       ` Paul Mackerras
2011-05-17  8:21   ` Alexander Graf
2011-05-17  8:21     ` Alexander Graf
2011-05-17 10:44     ` Paul Mackerras
2011-05-17 11:36       ` Alexander Graf
2011-05-17 11:36         ` Alexander Graf
2011-05-19  6:06         ` Paul Mackerras
2011-05-17  9:46 ` [PATCH 0/13] Hypervisor-mode KVM on POWER7 Alexander Graf
2011-05-17  9:46   ` Alexander Graf
2011-05-17 11:15   ` Paul Mackerras
2011-05-17 11:38     ` Alexander Graf
2011-05-17 11:38       ` Alexander Graf
2011-05-17 11:42       ` Avi Kivity
2011-05-17 11:42         ` Avi Kivity
2011-05-19  5:22         ` Paul Mackerras
2011-05-19  5:22           ` Paul Mackerras
2011-05-19  6:01           ` Alexander Graf
2011-05-19  6:01             ` Alexander Graf
2011-05-19  6:01             ` Alexander Graf
2011-05-21 16:41           ` Alexander Graf
2011-05-21 16:41             ` Alexander Graf
2011-05-21 17:00             ` Alexander Graf
2011-05-21 17:00               ` Alexander Graf
2011-05-21 18:15               ` Alexander Graf
2011-05-21 18:15                 ` Alexander Graf

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