From: Jason Gunthorpe <jgg@nvidia.com>
To: Alexey Kardashevskiy <aik@amd.com>
Cc: "David Hildenbrand" <david@redhat.com>,
"Chenyi Qiang" <chenyi.qiang@intel.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Peter Xu" <peterx@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>,
"Michael Roth" <michael.roth@amd.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
"Williams Dan J" <dan.j.williams@intel.com>,
"Peng Chao P" <chao.p.peng@intel.com>,
"Gao Chao" <chao.gao@intel.com>, "Xu Yilun" <yilun.xu@intel.com>
Subject: Re: [PATCH 0/7] Enable shared device assignment
Date: Wed, 15 Jan 2025 08:49:33 -0400 [thread overview]
Message-ID: <20250115124933.GL5556@nvidia.com> (raw)
In-Reply-To: <9d925eaa-ba32-41f4-8845-448d26cef4c7@amd.com>
On Wed, Jan 15, 2025 at 02:39:55PM +1100, Alexey Kardashevskiy wrote:
> > The thread was talking about the built-in support in iommufd to split
> > mappings.
>
> Just to clarify - I am talking about splitting only "iommufd areas", not
> large pages.
In generality it is the same thing as you cannot generally guarantee
that an area split doesn't also cross a large page.
> If all IOMMU PTEs are 4k and areas are bigger than 4K => the hw
> support is not needed to allow splitting. The comments above and below seem
> to confuse large pages with large areas (well, I am consufed, at least).
Yes, in that special case yes.
> > That built-in support is only accessible through legacy APIs
> > and should never be used in new qemu code. To use that built in
> > support in new code we need to build new APIs.
>
> Why would not IOMMU_IOAS_MAP/UNMAP uAPI work? Thanks,
I don't want to overload those APIs, I prefer to see a new API that is
just about splitting areas. Splitting is a special operation that can
fail depending on driver support.
Jason
next prev parent reply other threads:[~2025-01-15 12:49 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-13 7:08 [PATCH 0/7] Enable shared device assignment Chenyi Qiang
2024-12-13 7:08 ` [PATCH 1/7] memory: Export a helper to get intersection of a MemoryRegionSection with a given range Chenyi Qiang
2024-12-18 12:33 ` David Hildenbrand
2025-01-08 4:47 ` Alexey Kardashevskiy
2025-01-08 6:41 ` Chenyi Qiang
2025-01-20 12:50 ` David Hildenbrand
2024-12-13 7:08 ` [PATCH 2/7] guest_memfd: Introduce an object to manage the guest-memfd with RamDiscardManager Chenyi Qiang
2024-12-18 6:45 ` Chenyi Qiang
2025-01-08 4:48 ` Alexey Kardashevskiy
2025-01-08 10:56 ` Chenyi Qiang
2025-01-08 11:20 ` Alexey Kardashevskiy
2025-01-09 2:11 ` Chenyi Qiang
2025-01-09 2:55 ` Alexey Kardashevskiy
2025-01-09 4:29 ` Chenyi Qiang
2025-01-10 0:58 ` Alexey Kardashevskiy
2025-01-10 6:38 ` Chenyi Qiang
2025-01-09 21:00 ` Xu Yilun
2025-01-09 21:50 ` Xu Yilun
2025-01-13 3:34 ` Chenyi Qiang
2025-01-12 22:23 ` Xu Yilun
2025-01-14 1:14 ` Chenyi Qiang
2025-01-15 4:06 ` Alexey Kardashevskiy
2025-01-15 6:15 ` Chenyi Qiang
2025-01-20 10:22 ` Alexey Kardashevskiy
2025-01-20 20:46 ` Peter Xu
2024-06-24 16:31 ` Xu Yilun
2025-01-21 15:18 ` Peter Xu
2025-01-22 4:30 ` Alexey Kardashevskiy
2025-01-22 9:41 ` Xu Yilun
2025-01-22 16:43 ` Peter Xu
2025-01-23 9:33 ` Xu Yilun
2025-01-23 16:47 ` Peter Xu
2025-01-24 9:47 ` Xu Yilun
2025-01-24 15:55 ` Peter Xu
2025-01-24 18:17 ` David Hildenbrand
2025-01-26 3:34 ` Xu Yilun
2025-01-30 16:28 ` Peter Xu
2025-01-30 16:51 ` David Hildenbrand
2025-02-06 10:41 ` Xu Yilun
2025-02-06 20:03 ` Peter Xu
2025-01-14 6:45 ` Chenyi Qiang
2025-01-13 10:54 ` David Hildenbrand
2025-01-14 1:10 ` Chenyi Qiang
2025-01-15 4:05 ` Alexey Kardashevskiy
2025-01-20 10:48 ` David Hildenbrand
2025-01-20 17:21 ` Peter Xu
2025-01-20 17:54 ` David Hildenbrand
2025-01-20 18:33 ` Peter Xu
2025-01-20 18:47 ` David Hildenbrand
2025-01-20 20:19 ` Peter Xu
2025-01-20 20:25 ` David Hildenbrand
2025-01-20 20:43 ` Peter Xu
2025-01-21 1:35 ` Chenyi Qiang
2025-01-21 16:35 ` Peter Xu
2025-01-22 3:28 ` Chenyi Qiang
2025-01-22 5:38 ` Xiaoyao Li
2025-01-24 0:15 ` Alexey Kardashevskiy
2025-01-24 3:09 ` Chenyi Qiang
2025-01-24 5:56 ` Alexey Kardashevskiy
2025-01-24 16:12 ` Peter Xu
2025-01-20 18:09 ` Peter Xu
2025-01-21 9:00 ` Chenyi Qiang
2025-01-21 9:26 ` David Hildenbrand
2025-01-21 10:16 ` Chenyi Qiang
2025-01-21 10:26 ` David Hildenbrand
2025-01-22 6:43 ` Chenyi Qiang
2025-01-21 15:38 ` Peter Xu
2025-01-24 3:40 ` Chenyi Qiang
2024-12-13 7:08 ` [PATCH 3/7] guest_memfd: Introduce a callback to notify the shared/private state change Chenyi Qiang
2024-12-13 7:08 ` [PATCH 4/7] KVM: Notify the state change event during shared/private conversion Chenyi Qiang
2024-12-13 7:08 ` [PATCH 5/7] memory: Register the RamDiscardManager instance upon guest_memfd creation Chenyi Qiang
2025-01-08 4:47 ` Alexey Kardashevskiy
2025-01-09 5:34 ` Chenyi Qiang
2025-01-09 9:32 ` Alexey Kardashevskiy
2025-01-10 5:13 ` Chenyi Qiang
2025-01-20 13:06 ` David Hildenbrand
2025-01-24 3:27 ` Alexey Kardashevskiy
2025-01-24 5:36 ` Chenyi Qiang
2025-01-09 8:14 ` Zhao Liu
2025-01-09 8:17 ` Chenyi Qiang
2024-12-13 7:08 ` [PATCH 6/7] RAMBlock: make guest_memfd require coordinate discard Chenyi Qiang
2025-01-13 10:56 ` David Hildenbrand
2025-01-14 1:38 ` Chenyi Qiang
2025-01-20 13:11 ` David Hildenbrand
2025-01-21 6:26 ` Chenyi Qiang
2025-01-21 8:05 ` David Hildenbrand
2024-12-13 7:08 ` [RFC PATCH 7/7] memory: Add a new argument to indicate the request attribute in RamDismcardManager helpers Chenyi Qiang
2025-01-08 4:47 ` [PATCH 0/7] Enable shared device assignment Alexey Kardashevskiy
2025-01-08 6:28 ` Chenyi Qiang
2025-01-08 11:38 ` Alexey Kardashevskiy
2025-01-09 7:52 ` Chenyi Qiang
2025-01-09 8:18 ` Alexey Kardashevskiy
2025-01-09 8:49 ` Chenyi Qiang
2025-01-10 1:42 ` Alexey Kardashevskiy
2025-01-10 7:06 ` Chenyi Qiang
2025-01-10 8:26 ` David Hildenbrand
2025-01-10 13:20 ` Jason Gunthorpe
2025-01-10 13:45 ` David Hildenbrand
2025-01-10 14:14 ` Jason Gunthorpe
2025-01-10 14:50 ` David Hildenbrand
2025-01-15 3:39 ` Alexey Kardashevskiy
2025-01-15 12:49 ` Jason Gunthorpe [this message]
2025-01-20 12:57 ` David Hildenbrand
2025-01-20 18:39 ` Jason Gunthorpe
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