Date: Sat, 15 Aug 2015 10:30:27 -0500 From: Jason Harmening <jason.harmening@gmail.com> To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <royger@FreeBSD.org>, "Jason A. Harmening" <jah@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r286787 - head/sys/x86/x86 Message-ID: <55CF5B13.1040501@gmail.com> In-Reply-To: <55CF390F.5010407@FreeBSD.org> References: <201508142008.t7EK8Hkt037329@repo.freebsd.org> <55CF390F.5010407@FreeBSD.org>
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On 08/15/15 08:05, Roger Pau Monné wrote: > El 14/08/15 a les 22.08, Jason A. Harmening ha escrit: >> Author: jah >> Date: Fri Aug 14 20:08:16 2015 >> New Revision: 286787 >> URL: https://svnweb.freebsd.org/changeset/base/286787 >> >> Log: >> Use pmap_quick_enter_page() to handle bouncing of unmapped buffers in the x86 busdma_bounce implementation. Also treat user buffers as unmapped. >> This allows two things: >> 1. Sync'ing bounced maps in non-sleepable contexts. The physcopy* calls previously used could sleep on sf_buf operations in some cases. >> 2. Sync'ing user buffers outside the context of the owning process > > AFAICT this will break the Xen port. physcopy* uses uiomove_fromphys > that on the amd64 port is able to deal with pages outside of the DMAP. > OTOH pmap_quick_enter_page is not able to deal with pages outside of the > DMAP, and will simply panic. > > Roger. > Is it actually possible for those non-dom0 pages to be used for I/O that passes through busdma? If it is, then it would be easy to make pmap_quick_enter_page() handle them by adding a pcpu pageframe similar to what we do for i386.
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