From: Paolo Bonzini <pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Graham Neville
<grahamneville-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"Bridgman, John" <John.Bridgman-5C7GfCeVMHo@public.gmane.org>
Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org"
<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
"kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Matthias Ehrenfeuchter
<efeu-5Zrl/DuVEGLQT0dZR+AlfA@public.gmane.org>
Subject: Re: AMD Ryzen KVM/NPT/IOMMU issue
Date: Wed, 28 Jun 2017 22:33:45 +0200 [thread overview]
Message-ID: <ecfb6f20-6f74-3d46-b3fb-696d36ab4008@redhat.com> (raw)
In-Reply-To: <CAEk7i1-Ar0ES8ekmSGiRrrWzTz8gFb2RDTW6KsbuNdDubVerww-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On 28/06/2017 21:52, Graham Neville wrote:
> Although not related to graphics card performance, there is definitely
> another issue with regards to running KVM nested L2 guests when npt=1.
>
> Thought I'd mention this in case it helps with identifying performance
> issues with NPT.
>
> I'm unable to start any L2 guests with KVM acceleration (--enable-kvm).
> As soon as it attempts to bring up the L2 guest the L1 host crashes, L0
> host remains online. Nothing is printed in either L1 or L0's dmesg.
>
> My L0 is running Arch with 4.11.0-rc6, with qemu 2.8.0. I've tried
> different L1 hosts (Ubuntu,Arch) and different kernels right to 4.12-rc5
> kernel, along with different qemu versions.
>
> This used to work fine with my Intel i7-4770s setup.
>
> With npt=0, L2 guests can start but performance is dier.
Nested AMD needs some care. It's known, but time has been lacking...
Paolo
next prev parent reply other threads:[~2017-06-28 20:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <575f8fbc-0fdc-f336-e3da-53f27da4b2e1@markju.com>
[not found] ` <CAOcCaLbdi9KZoXiV5htjShc_mYvZ5jK2B3Ot7NeM=3v_ZA39aA@mail.gmail.com>
2017-05-05 17:27 ` AMD Ryzen KVM/NPT/IOMMU issue Alex Williamson
[not found] ` <20170505112706.7785948c-1yVPhWWZRC1BDLzU/O5InQ@public.gmane.org>
2017-06-25 5:55 ` Nick Sarnie
[not found] ` <CAOcCaLbAS0FkRrG8YZNM5rYUtCFeUGkdgdy=4o16Njufdy8Gag-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-28 17:23 ` Suravee Suthikulpanit
2017-06-28 17:26 ` Steven Walter
[not found] ` <CAK8d-aJ+XHi+5sr6bHj3D2BaG94v6Lyk1C_ZuA4erDVhEyp-uQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-28 18:53 ` Suravee Suthikulpanit
[not found] ` <5d2ea709-8f90-bfaa-975d-48aed39e75ad-5C7GfCeVMHo@public.gmane.org>
2017-06-28 19:08 ` Alex Williamson
[not found] ` <20170628130855.76c2b700-DGNDKt5SQtizQB+pC5nmwQ@public.gmane.org>
2017-06-28 19:28 ` Bridgman, John
2017-06-28 19:29 ` Bridgman, John
[not found] ` <BN6PR12MB13481A39CD3EA714754FEE49E8DD0-/b2+HYfkarQX0pEhCR5T8QdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-06-28 19:52 ` Graham Neville
[not found] ` <CAEk7i1-Ar0ES8ekmSGiRrrWzTz8gFb2RDTW6KsbuNdDubVerww-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-28 20:33 ` Paolo Bonzini [this message]
2017-06-28 22:34 ` Nick Sarnie
[not found] ` <CAOcCaLao_Y-8KP60baoSehtCu7C5CVnuuZNEom-zi54Fa2h+sQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-29 0:21 ` Thiago Padilha
[not found] ` <CAAq2Xdpu_rv7FgVfGCv-nYttGzH6hZujqdYvcf4qgXetkOGLzw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-29 1:50 ` Thiago Padilha
[not found] ` <CAAq2XdppNcKcmbJhPQ9WfTowKSmp76jhDa9JHM1rc92Enx=1Zg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-29 1:54 ` Nick Sarnie
2017-07-01 14:15 ` Thiago Padilha
2017-10-17 4:16 ` Nick Sarnie
[not found] ` <545f19a3-4923-cdec-4ce9-2a4155a04f6a-5C7GfCeVMHo@public.gmane.org>
2017-06-28 17:31 ` Alex Williamson
[not found] <b88fc14b230d7ecac6066bdd9e95be19@hostfission.com>
[not found] ` <cb2b1ee0a3b705e668ac3cf19cfa1ecc@hostfission.com>
[not found] ` <1b4a39530fde35783be63470003f0911@hostfission.com>
[not found] ` <f0680cfe52b9196ee4a1d3ab28a7aefa@hostfission.com>
2017-10-24 21:31 ` Alex Williamson
[not found] ` <20171024233137.295a6b39-1yVPhWWZRC1BDLzU/O5InQ@public.gmane.org>
2017-10-24 21:39 ` geoff--- via iommu
[not found] ` <a909bd77b381f5beef6d74c97307265d-9M2dFRIgpjGrDvn5mFPilA@public.gmane.org>
2017-10-24 23:39 ` Nick Sarnie
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