From: Hongyan Xia <hx242@xen.org>
To: Jan Beulich <jbeulich@suse.com>, Wei Liu <wl@xen.org>
Cc: xen-devel@lists.xenproject.org,
"Roger Pau Monné" <roger.pau@citrix.com>,
julien@xen.org, "Andrew Cooper" <andrew.cooper3@citrix.com>
Subject: Re: [PATCH 5/6] x86/pv: map and unmap page tables in mark_pv_pt_pages_rdonly
Date: Wed, 29 Apr 2020 10:26:19 +0100 [thread overview]
Message-ID: <e18871ea997a304394adbbc92e724ae0ec56d87a.camel@xen.org> (raw)
In-Reply-To: <c33dcaee9c8796da8816de9168f91ce90de61fc5.camel@xen.org>
On Tue, 2020-04-28 at 16:59 +0100, Hongyan Xia wrote:
> On Tue, 2020-04-28 at 16:55 +0100, Hongyan Xia wrote:
> > On Tue, 2020-04-28 at 17:33 +0200, Jan Beulich wrote:
> > > On 17.04.2020 11:52, Hongyan Xia wrote:
> > > > --- a/xen/arch/x86/pv/dom0_build.c
> > > > +++ b/xen/arch/x86/pv/dom0_build.c
> > > > @@ -50,17 +50,17 @@ static __init void
> > > > mark_pv_pt_pages_rdonly(struct domain *d,
> > > > unsigned long count;
> > > > struct page_info *page;
> > > > l4_pgentry_t *pl4e;
> > > > - l3_pgentry_t *pl3e;
> > > > - l2_pgentry_t *pl2e;
> > > > - l1_pgentry_t *pl1e;
> > > > + l3_pgentry_t *pl3e, *l3t;
> > > > + l2_pgentry_t *pl2e, *l2t;
> > > > + l1_pgentry_t *pl1e, *l1t;
> > >
> > > I don't quite see why the new local variables get introduced:
> > > unmap_domain_page(), iirc, is quite fine with a non-page-
> > > aligned argument.
> >
> > You are right, although in this function, where plXe points to may
> > not
> > be the page we want to unmap. When plXe becomes aligned and points
> > to
> > a
> > new page, we actually want to unmap the page before it increments
> > to
> > an
> > aligned value.
>
> Hmm, we can just unmap(plXe - 1) if my logic is correct, and save 3
> local variables.
Sorry for monologuing, but I still prefer separating plXe and lXt
because it makes it clear what we are unmapping. Unmapping plXe - 1 is
a bit hackish.
But if people do not have a problem with plXe - 1, I will post a new
revision for that.
Hongyan
next prev parent reply other threads:[~2020-04-29 9:26 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-17 9:52 [PATCH 0/6] convert more Xen page table code to the new API Hongyan Xia
2020-04-17 9:52 ` [PATCH 1/6] x86_64/mm: map and unmap page tables in cleanup_frame_table Hongyan Xia
2020-04-24 8:58 ` Julien Grall
2020-04-24 8:59 ` Julien Grall
2020-04-24 8:59 ` Julien Grall
2020-04-24 9:21 ` Hongyan Xia
2020-04-24 9:24 ` Julien Grall
2020-04-24 9:02 ` Julien Grall
2020-04-24 11:12 ` Jan Beulich
2020-04-28 15:11 ` Jan Beulich
2020-04-17 9:52 ` [PATCH 2/6] x86_64/mm: map and unmap page tables in subarch_init_memory Hongyan Xia
2020-04-24 9:04 ` Julien Grall
2020-04-28 15:12 ` Jan Beulich
2020-04-17 9:52 ` [PATCH 3/6] x86_64/mm: map and unmap page tables in subarch_memory_op Hongyan Xia
2020-04-24 9:06 ` Julien Grall
2020-04-28 15:23 ` Jan Beulich
2020-04-17 9:52 ` [PATCH 4/6] x86/smpboot: map and unmap page tables in cleanup_cpu_root_pgt Hongyan Xia
2020-04-24 9:13 ` Julien Grall
2020-04-28 15:26 ` Jan Beulich
2020-04-17 9:52 ` [PATCH 5/6] x86/pv: map and unmap page tables in mark_pv_pt_pages_rdonly Hongyan Xia
2020-04-24 9:16 ` Julien Grall
2020-04-28 15:33 ` Jan Beulich
2020-04-28 15:49 ` Wei Liu
2020-04-28 15:55 ` Hongyan Xia
2020-04-28 15:59 ` Hongyan Xia
2020-04-29 9:26 ` Hongyan Xia [this message]
2020-04-29 11:04 ` Jan Beulich
2020-04-29 12:29 ` Hongyan Xia
2020-04-29 13:31 ` Jan Beulich
2020-04-17 9:52 ` [PATCH 6/6] x86/pv: map and unmap page table in dom0_construct_pv Hongyan Xia
2020-04-24 9:18 ` Julien Grall
2020-04-28 15:34 ` Jan Beulich
2020-04-24 8:07 ` [PATCH 0/6] convert more Xen page table code to the new API Hongyan Xia
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