Messages in this thread | | | Date | Tue, 31 May 2022 13:27:24 -0400 | Subject | Re: [PATCH] xen: replace xen_remap() with memremap() | From | Boris Ostrovsky <> |
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On 5/30/22 4:26 AM, Juergen Gross wrote: > xen_remap() is used to establish mappings for frames not under direct > control of the kernel: for Xenstore and console ring pages, and for > grant pages of non-PV guests. > > Today xen_remap() is defined to use ioremap() on x86 (doing uncached > mappings), and ioremap_cache() on Arm (doing cached mappings). > > Uncached mappings for those use cases are bad for performance, so they > should be avoided if possible. As all use cases of xen_remap() don't > require uncached mappings (the mapped area is always physical RAM), > a mapping using the standard WB cache mode is fine. > > As sparse is flagging some of the xen_remap() use cases to be not > appropriate for iomem(), as the result is not annotated with the > __iomem modifier, eliminate xen_remap() completely and replace all > use cases with memremap() specifying the MEMREMAP_WB caching mode. > > xen_unmap() can be replaced with memunmap(). > > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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