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Tue, 03 Aug 2021 13:30:22 +0000 (UTC) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id BD7A35C0189; Tue, 3 Aug 2021 09:30:21 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Tue, 03 Aug 2021 09:30:21 -0400 Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 3 Aug 2021 09:30:20 -0400 (EDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 2c1a54ea-2dae-4866-a66e-4f27d75ddee9 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=njCeVW Hkp3+kQIDTRaLIg71XMaVis2WbAirdeXdxvAU=; b=MVVHjQpfLoRbR04Ne5OM1w Khp4xyRd4mNpPbZqSBPzsxbQwPVhkjoXCj6MrH7g/fcf4T+i3v54NATxr1+oJxV2 V7VSBSp4FkN1V3iXYJSiQulurvE5BD8oQihJjcYfu5HoYM8Vui79q0nXNGYqJMYq HnktnetKzfXVhgv1Ksdtt6ZSgq89yuuJpwSODA6cp6ZeAxvxbHIk4kquppEHBiZK yjOblYuDtMtHBArrQu6eG5BDBmLBwqEkDMCjiOMrBlM0f8nPLgUvaAVF1K73OcyT 31S6PBFtojwjFjMPrV9KZ8/mEHcI8zinxO00HDjm133qxO6ONppM0UA7quLgXf0g == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvtddrieeggdeivdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvuffkfhggtggujgesghdtreertddtjeenucfhrhhomhepofgrrhgvkhcu ofgrrhgtiiihkhhofihskhhiqdfikphrvggtkhhiuceomhgrrhhmrghrvghksehinhhvih hsihgslhgvthhhihhnghhslhgrsgdrtghomheqnecuggftrfgrthhtvghrnhepteevffei gffhkefhgfegfeffhfegveeikeettdfhheevieehieeitddugeefteffnecuvehluhhsth gvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepmhgrrhhmrghrvghksehi nhhvihhsihgslhgvthhhihhnghhslhgrsgdrtghomh X-ME-Proxy: Date: Tue, 3 Aug 2021 15:30:17 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Jan Beulich Cc: "xen-devel@lists.xenproject.org" , Kevin Tian , Andrew Cooper Subject: Re: [PATCH] VT-d: Tylersburg errata apply to further steppings Message-ID: References: <07ded368-5c12-c06e-fd94-d7ae52d18836@suse.com> <10425176-438f-370b-9d60-183d6e0f5441@suse.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="1nzrRTmZWqHMh/1X" Content-Disposition: inline In-Reply-To: --1nzrRTmZWqHMh/1X Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Tue, 3 Aug 2021 15:30:17 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Jan Beulich Cc: "xen-devel@lists.xenproject.org" , Kevin Tian , Andrew Cooper Subject: Re: [PATCH] VT-d: Tylersburg errata apply to further steppings On Tue, Aug 03, 2021 at 03:16:14PM +0200, Jan Beulich wrote: > On 03.08.2021 15:12, Marek Marczykowski-G=C3=B3recki wrote: > > On Tue, Aug 03, 2021 at 03:06:50PM +0200, Jan Beulich wrote: > >> On 03.08.2021 15:01, Marek Marczykowski-G=C3=B3recki wrote: > >>> Ok, then, just setting iommu_intremap=3Dfalse should do the right thi= ng, > >> > >> ... if "iommu=3Dforce" is in use (but not otherwise), ... > >=20 > > But that's the purpose of iommu=3Dforce, no? > > With "iommu=3Dforce": strictly require IOMMU > > Without "iommu=3Dforce": use IOMMU on best-effort basis > >=20 > > It makes sense to refuse the boot if intremap is broken in the first > > case. But also, it makes sense to allow using IOMMU without intremp in > > the second case. >=20 > I agree with both statements. What I disagree with is that the latter > happens by default (instead of only upon admin override), including > the case of intremap being unavailable in the first place. "upon admin override" - do I read the code right, that iommu=3Dno-intremap will actually achieve this effect? Will that allow to use IOMMU without interrupt remapping on a hardware where it's broken? In that case, maybe at least add this info to the log message? IMO an option to strictly require interrupt remapping would be useful thing to have, but that's getting even more unrelated to this bug fix. --=20 Best Regards, Marek Marczykowski-G=C3=B3recki Invisible Things Lab --1nzrRTmZWqHMh/1X Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmEJROkACgkQ24/THMrX 1yyYigf9GhHUnocbjQxWGp5xyepJV7B/P4bsjRH9H0ZFKFCqV35sqr3D5W4UwkIu 1pQtXLuTC657U6WeSCoe3tlgKkVwYm/vQ++XRnUqwqBYpvcQgBODgKmGBl8oEif1 Qn8R2WgpYaqUFIdOJvIH01tI8nKzZrU1pL9hE7fsfKLTeUQt/wOScAUJqqUV1trh DqtD0YAytv9zNiuVXBmREMrfR0tqk3mkRWxR2I1q08yh+UsftOXJFwXGhe72dxiB zYsJFECUSp/1JOTd+xEGOKN+kqFx5zCaS1NcgFJP5ziTDpWS4aHxyAb+4xKEeok3 VDM9ta4BuHUwBlTOnLe0jFrW1AUMaw== =e2X7 -----END PGP SIGNATURE----- --1nzrRTmZWqHMh/1X--