From: Stefano Stabellini <sstabellini@kernel.org> To: Julien Grall <julien.grall@gmail.com> Cc: xen-devel <xen-devel@lists.xenproject.org>, Julien Grall <julien.grall@arm.com>, Stefano Stabellini <sstabellini@kernel.org>, nd <nd@arm.com>, Stefano Stabellini <stefanos@xilinx.com> Subject: Re: [PATCH 5/6] xen/arm: map reserved-memory regions as normal memory in dom0 Date: Tue, 23 Apr 2019 14:34:44 -0700 (PDT) [thread overview] Message-ID: <alpine.DEB.2.10.1904231356000.24598@sstabellini-ThinkPad-X260> (raw) In-Reply-To: <CAF3u54CD7O0swVyTwMshxUhxnLg56=iF9S1xb5vKjuZq-F9BKQ@mail.gmail.com> [-- Attachment #1: Type: TEXT/PLAIN, Size: 2876 bytes --] On Tue, 23 Apr 2019, Julien Grall wrote: > Hi, > > Sorry for the formatting. > > On Tue, 23 Apr 2019, 18:34 Stefano Stabellini, <sstabellini@kernel.org> wrote: > On Tue, 23 Apr 2019, Julien Grall wrote: > > Hi Stefano, > > > > On 4/22/19 11:42 PM, Stefano Stabellini wrote: > > > On Tue, 26 Feb 2019, Julien Grall wrote: > > > I am not sure about the suggestion of re-using the libfdt concept of > > > "mem_rsv", which is meant to be for the old /memreserve/. Today, libfdt > > > (at least our version of it) is not able to parse the new > > > reserved-memory bindings. I don't think it is a good idea to modify > > > libfdt for that. Also, the way we want to handle the old memreserve > > > regions is quite different from the way we want to handle > > > reserved-memory, right? I cannot see a way to improve this code using > > > mem_rsv at the moment. > > > > I didn't mean to extend mem_rsv in libfdt but extend consider_modules and > > dt_unreserved_regions to deal with /reserved-memory. Otherwise you > > may miss some cases (for instance you left out discard_initial_modules). > > > > By extending those two functions you don't have to teach everyone how to skip > > /reserved-memory. > > I think I get your point now. Although I don't think it should be > correct for a bootloader to use a reserved-memory area to store a boot > module, I wouldn't be suprised if that happens, so it is better to be > prepared and extend dt_unreserved_regions. I'll do that. > > However, we would still need something like check_reserved_memory, > because we don't want setup_xenheap_mappings to be called on the > reserved-memory area (or a memory region including the reserved memory > area) in setup_mm. I don't think we can get away without it, but I can > simplify it. > > > Hmmm, setup_xenheap_mappings is only doing the mapping in page-tables allowing direct access in Xen. Are you worried of the > memory attributes to be different in Xen? Yes; also we don't need the mappings in Xen. > This would makes sense however setup_xenheap_mappings may still map the reserved-memory because it is using 1G mapping... This is > pretty wrong and I have patches that should help to fix it. I didn't notice it :-/ > Also if you are concerned with /reserved-memory, then it should also be fixed for /mem-reserve as they are not different. I understand. > However, this may break free_initmem as because we try to give back page to xenheap even if they are reserved. > > The memory management is quite a mess today. I hope to make it better with my upcoming series. I am going to follow your original suggestion of dropping most of the changes from this patch and rely on the existing functions. [-- Attachment #2: Type: text/plain, Size: 157 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
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From: Stefano Stabellini <sstabellini@kernel.org> To: Julien Grall <julien.grall@gmail.com> Cc: xen-devel <xen-devel@lists.xenproject.org>, Julien Grall <julien.grall@arm.com>, Stefano Stabellini <sstabellini@kernel.org>, nd <nd@arm.com>, Stefano Stabellini <stefanos@xilinx.com> Subject: Re: [Xen-devel] [PATCH 5/6] xen/arm: map reserved-memory regions as normal memory in dom0 Date: Tue, 23 Apr 2019 14:34:44 -0700 (PDT) [thread overview] Message-ID: <alpine.DEB.2.10.1904231356000.24598@sstabellini-ThinkPad-X260> (raw) Message-ID: <20190423213444.MSF2jyGr4ASjKMAKS68isu7MxOphGrXsZZWnjHOyxGM@z> (raw) In-Reply-To: <CAF3u54CD7O0swVyTwMshxUhxnLg56=iF9S1xb5vKjuZq-F9BKQ@mail.gmail.com> [-- Attachment #1: Type: TEXT/PLAIN, Size: 2876 bytes --] On Tue, 23 Apr 2019, Julien Grall wrote: > Hi, > > Sorry for the formatting. > > On Tue, 23 Apr 2019, 18:34 Stefano Stabellini, <sstabellini@kernel.org> wrote: > On Tue, 23 Apr 2019, Julien Grall wrote: > > Hi Stefano, > > > > On 4/22/19 11:42 PM, Stefano Stabellini wrote: > > > On Tue, 26 Feb 2019, Julien Grall wrote: > > > I am not sure about the suggestion of re-using the libfdt concept of > > > "mem_rsv", which is meant to be for the old /memreserve/. Today, libfdt > > > (at least our version of it) is not able to parse the new > > > reserved-memory bindings. I don't think it is a good idea to modify > > > libfdt for that. Also, the way we want to handle the old memreserve > > > regions is quite different from the way we want to handle > > > reserved-memory, right? I cannot see a way to improve this code using > > > mem_rsv at the moment. > > > > I didn't mean to extend mem_rsv in libfdt but extend consider_modules and > > dt_unreserved_regions to deal with /reserved-memory. Otherwise you > > may miss some cases (for instance you left out discard_initial_modules). > > > > By extending those two functions you don't have to teach everyone how to skip > > /reserved-memory. > > I think I get your point now. Although I don't think it should be > correct for a bootloader to use a reserved-memory area to store a boot > module, I wouldn't be suprised if that happens, so it is better to be > prepared and extend dt_unreserved_regions. I'll do that. > > However, we would still need something like check_reserved_memory, > because we don't want setup_xenheap_mappings to be called on the > reserved-memory area (or a memory region including the reserved memory > area) in setup_mm. I don't think we can get away without it, but I can > simplify it. > > > Hmmm, setup_xenheap_mappings is only doing the mapping in page-tables allowing direct access in Xen. Are you worried of the > memory attributes to be different in Xen? Yes; also we don't need the mappings in Xen. > This would makes sense however setup_xenheap_mappings may still map the reserved-memory because it is using 1G mapping... This is > pretty wrong and I have patches that should help to fix it. I didn't notice it :-/ > Also if you are concerned with /reserved-memory, then it should also be fixed for /mem-reserve as they are not different. I understand. > However, this may break free_initmem as because we try to give back page to xenheap even if they are reserved. > > The memory management is quite a mess today. I hope to make it better with my upcoming series. I am going to follow your original suggestion of dropping most of the changes from this patch and rely on the existing functions. [-- Attachment #2: Type: text/plain, Size: 157 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2019-04-23 21:34 UTC|newest] Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-02-26 23:06 [PATCH 0/6] iomem cacheability Stefano Stabellini 2019-02-26 23:07 ` [PATCH 1/6] xen: extend XEN_DOMCTL_memory_mapping to handle cacheability Stefano Stabellini 2019-02-26 23:18 ` Julien Grall 2019-04-20 0:02 ` Stefano Stabellini 2019-04-20 0:02 ` [Xen-devel] " Stefano Stabellini 2019-04-21 17:32 ` Julien Grall 2019-04-21 17:32 ` [Xen-devel] " Julien Grall 2019-04-22 21:59 ` Stefano Stabellini 2019-04-22 21:59 ` [Xen-devel] " Stefano Stabellini 2019-04-24 10:42 ` Julien Grall 2019-04-24 10:42 ` [Xen-devel] " Julien Grall 2019-02-27 10:34 ` Jan Beulich 2019-04-17 21:12 ` Stefano Stabellini 2019-04-17 21:12 ` [Xen-devel] " Stefano Stabellini 2019-04-17 21:25 ` Julien Grall 2019-04-17 21:25 ` [Xen-devel] " Julien Grall 2019-04-17 21:55 ` Stefano Stabellini 2019-04-17 21:55 ` [Xen-devel] " Stefano Stabellini 2019-04-25 10:41 ` Jan Beulich 2019-04-25 10:41 ` [Xen-devel] " Jan Beulich 2019-04-25 22:31 ` Stefano Stabellini 2019-04-25 22:31 ` [Xen-devel] " Stefano Stabellini 2019-04-26 7:12 ` Jan Beulich 2019-04-26 7:12 ` [Xen-devel] " Jan Beulich 2019-02-27 19:28 ` Julien Grall 2019-04-19 23:20 ` Stefano Stabellini 2019-04-19 23:20 ` [Xen-devel] " Stefano Stabellini 2019-04-21 17:14 ` Julien Grall 2019-04-21 17:14 ` [Xen-devel] " Julien Grall 2019-04-22 17:33 ` Stefano Stabellini 2019-04-22 17:33 ` [Xen-devel] " Stefano Stabellini 2019-04-22 17:42 ` Julien Grall 2019-04-22 17:42 ` [Xen-devel] " Julien Grall 2019-02-27 21:02 ` Julien Grall 2019-02-26 23:07 ` [PATCH 2/6] libxc: xc_domain_memory_mapping, " Stefano Stabellini 2019-02-26 23:07 ` [PATCH 3/6] libxl/xl: add cacheability option to iomem Stefano Stabellini 2019-02-27 20:02 ` Julien Grall 2019-04-19 23:13 ` Stefano Stabellini 2019-04-19 23:13 ` [Xen-devel] " Stefano Stabellini 2019-02-26 23:07 ` [PATCH 4/6] xen/arm: keep track of reserved-memory regions Stefano Stabellini 2019-02-28 14:38 ` Julien Grall 2019-02-26 23:07 ` [PATCH 5/6] xen/arm: map reserved-memory regions as normal memory in dom0 Stefano Stabellini 2019-02-26 23:45 ` Julien Grall 2019-04-22 22:42 ` Stefano Stabellini 2019-04-22 22:42 ` [Xen-devel] " Stefano Stabellini 2019-04-23 8:09 ` Julien Grall 2019-04-23 8:09 ` [Xen-devel] " Julien Grall 2019-04-23 17:32 ` Stefano Stabellini 2019-04-23 17:32 ` [Xen-devel] " Stefano Stabellini 2019-04-23 18:37 ` Julien Grall 2019-04-23 18:37 ` [Xen-devel] " Julien Grall 2019-04-23 21:34 ` Stefano Stabellini [this message] 2019-04-23 21:34 ` Stefano Stabellini 2019-02-26 23:07 ` [PATCH 6/6] xen/docs: how to map a page between dom0 and domU using iomem Stefano Stabellini 2019-03-03 17:20 ` [PATCH 0/6] iomem cacheability Amit Tomer 2019-03-05 21:22 ` Stefano Stabellini 2019-03-05 22:45 ` Julien Grall 2019-03-06 11:46 ` Amit Tomer 2019-03-06 22:42 ` Stefano Stabellini 2019-03-06 22:59 ` Julien Grall 2019-03-07 8:42 ` Amit Tomer 2019-03-07 10:04 ` Julien Grall 2019-03-07 21:24 ` Stefano Stabellini 2019-03-08 10:10 ` Amit Tomer 2019-03-08 16:37 ` Julien Grall 2019-03-08 17:44 ` Amit Tomer 2019-03-06 11:30 ` Amit Tomer
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