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Re: [Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very l
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region |
Date: |
Tue, 24 Jan 2017 09:32:07 -0700 |
On Tue, 24 Jan 2017 18:25:56 +0800
Peter Xu <address@hidden> wrote:
> Linux vfio driver supports to do VFIO_IOMMU_UNMAP_DMA for a very big
> region. This can be leveraged by QEMU IOMMU implementation to cleanup
> existing page mappings for an entire iova address space (by notifying
> with an IOTLB with extremely huge addr_mask). However current
> vfio_iommu_map_notify() does not allow that. It make sure that all the
> translated address in IOTLB is falling into RAM range.
>
> The check makes sense, but it should only be a sensible checker for
> mapping operations, and mean little for unmap operations.
>
> This patch moves this check into map logic only, so that we'll get
> faster unmap handling (no need to translate again), and also we can then
> better support unmapping a very big region when it covers non-ram ranges
> or even not-existing ranges.
>
> Signed-off-by: Peter Xu <address@hidden>
> ---
> hw/vfio/common.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index ce55dff..4d90844 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -354,11 +354,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n,
> IOMMUTLBEntry *iotlb)
> return;
> }
>
> - if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> - return;
> - }
> -
> if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> + if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> + return;
> + }
David, is SPAPR going to freak out if it sees unmaps to ranges that
extend beyond individual mappings, or perhaps include no mappings?
This effectively allows unmapping the entire address space of the iommu
in one pass, without validating or translating the backing.
> ret = vfio_dma_map(container, iova,
> iotlb->addr_mask + 1, vaddr,
> read_only);
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), (continued)
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Alex Williamson, 2017/01/25
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Paolo Bonzini, 2017/01/25
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Alex Williamson, 2017/01/25
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Paolo Bonzini, 2017/01/25
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Alex Williamson, 2017/01/25
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Peter Xu, 2017/01/26
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Peter Xu, 2017/01/26
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Paolo Bonzini, 2017/01/26
- Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr(), Peter Xu, 2017/01/26
[Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region, Peter Xu, 2017/01/24
- Re: [Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region,
Alex Williamson <=
[Qemu-devel] [PATCH v5 04/18] intel_iommu: add "caching-mode" option, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 05/18] intel_iommu: simplify irq region translation, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 06/18] intel_iommu: renaming gpa to iova where proper, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 07/18] intel_iommu: fix trace for inv desc handling, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 09/18] intel_iommu: vtd_slpt_level_shift check level, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 08/18] intel_iommu: fix trace for addr translation, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 10/18] memory: add section range info for IOMMU notifier, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 11/18] memory: provide IOMMU_NOTIFIER_FOREACH macro, Peter Xu, 2017/01/24
[Qemu-devel] [PATCH v5 12/18] memory: provide iommu_replay_all(), Peter Xu, 2017/01/24