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micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="uurQj1kwzf6TNO7b" Content-Disposition: inline In-Reply-To: <93c7230a-bd2a-4763-a90a-89e02a169b1d@suse.com> --uurQj1kwzf6TNO7b Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Wed, 22 May 2024 17:22:23 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: Jan Beulich Cc: Andrew Cooper , Roger Pau =?utf-8?B?TW9ubsOp?= , xen-devel@lists.xenproject.org Subject: Re: [PATCH v3 1/2] x86/mm: add API for marking only part of a MMIO page read only On Wed, May 22, 2024 at 03:29:51PM +0200, Jan Beulich wrote: > On 22.05.2024 15:22, Marek Marczykowski-G=C3=B3recki wrote: > > On Wed, May 22, 2024 at 09:52:44AM +0200, Jan Beulich wrote: > >> On 21.05.2024 04:54, Marek Marczykowski-G=C3=B3recki wrote: > >>> +static void subpage_mmio_write_emulate( > >>> + mfn_t mfn, > >>> + unsigned int offset, > >>> + const void *data, > >>> + unsigned int len) > >>> +{ > >>> + struct subpage_ro_range *entry; > >>> + void __iomem *addr; > >> > >> Wouldn't this better be pointer-to-volatile, with ... > >=20 > > Shouldn't then most other uses of __iomem in the code base be this way > > too? I see volatile only in few places... >=20 > Quite likely, yet being consistent at least in new code is going to be > at least desirable. I tried. Build fails because iounmap() doesn't declare its argument as volatile, so it triggers -Werror=3Ddiscarded-qualifiers... I'll change it just in subpage_mmio_write_emulate(), but leave subpage_mmio_map_page() (was _get_page) without volatile. --=20 Best Regards, Marek Marczykowski-G=C3=B3recki Invisible Things Lab --uurQj1kwzf6TNO7b Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmZODbAACgkQ24/THMrX 1yyN5Af+OMhdFfQA18mjMg7vv7WCWIURPTVXlCsHUvpCnnXxlrkrhT6NCUwMimgW M1hS+jkbUHogu9rCxwad6hQ6Ex+OKat4qIVGep03NYoXFk+CyZJ0Ebv/QaLKTG27 8J4bqN3WHcaQxl6mTNB8S82iK1kpLdEaRWJJ4K8uhWdnL7Wg9FU6Rkce+wrqSH8m QF6xaGGrGo2MEHBKSQfi2KFsnu/gfSZlV8u5jm/FeUQJLK1WacrnYpG2GU6AmxoL x6J25dmVHG0Lr4z3v0KL0OrZX++pHcpW4ZQ14KQFv6zjA42IOSbAxSAi5zmrJOvj f2sydZ0SiiisCaCt3GC38i8EN5oZfA== =C0BQ -----END PGP SIGNATURE----- --uurQj1kwzf6TNO7b--