The code in question runs after module ranges got already removed from
the E820 table, so when determining the new maximum page/PDX we need to
explicitly take them into account.
Furthermore we need to round up the ending addresses here, in order to
fully cover eventual partial trailing pages.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1013,9 +1013,17 @@ void __init __start_xen(unsigned long mb
ASSERT(j);
}
map_e = boot_e820.map[j].addr + boot_e820.map[j].size;
- if ( (map_e >> PAGE_SHIFT) < max_page )
+ for ( j = 0; j < mbi->mods_count; ++j )
{
- max_page = map_e >> PAGE_SHIFT;
+ uint64_t end = pfn_to_paddr(mod[j].mod_start) +
+ mod[j].mod_end;
+
+ if ( map_e < end )
+ map_e = end;
+ }
+ if ( PFN_UP(map_e) < max_page )
+ {
+ max_page = PFN_UP(map_e);
max_pdx = pfn_to_pdx(max_page - 1) + 1;
}
printk(XENLOG_WARNING "Ignoring inaccessible memory
range"
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Keir Fraser
2013-Nov-18 11:32 UTC
Re: [PATCH] x86: consider modules when cutting off memory
On 18/11/2013 00:37, "Jan Beulich" <JBeulich@suse.com> wrote:> The code in question runs after module ranges got already removed from > the E820 table, so when determining the new maximum page/PDX we need to > explicitly take them into account. > > Furthermore we need to round up the ending addresses here, in order to > fully cover eventual partial trailing pages.Is rounding up the right thing to do? We round down in find_max_pfn()?> Signed-off-by: Jan Beulich <jbeulich@suse.com> > > --- a/xen/arch/x86/setup.c > +++ b/xen/arch/x86/setup.c > @@ -1013,9 +1013,17 @@ void __init __start_xen(unsigned long mb > ASSERT(j); > } > map_e = boot_e820.map[j].addr + boot_e820.map[j].size; > - if ( (map_e >> PAGE_SHIFT) < max_page ) > + for ( j = 0; j < mbi->mods_count; ++j ) > { > - max_page = map_e >> PAGE_SHIFT; > + uint64_t end = pfn_to_paddr(mod[j].mod_start) + > + mod[j].mod_end; > + > + if ( map_e < end ) > + map_e = end; > + } > + if ( PFN_UP(map_e) < max_page ) > + { > + max_page = PFN_UP(map_e); > max_pdx = pfn_to_pdx(max_page - 1) + 1; > } > printk(XENLOG_WARNING "Ignoring inaccessible memory range" > > >
Jan Beulich
2013-Nov-18 12:11 UTC
Re: [PATCH] x86: consider modules when cutting off memory
>>> On 18.11.13 at 12:32, Keir Fraser <keir.xen@gmail.com> wrote: > On 18/11/2013 00:37, "Jan Beulich" <JBeulich@suse.com> wrote: > >> The code in question runs after module ranges got already removed from >> the E820 table, so when determining the new maximum page/PDX we need to >> explicitly take them into account. >> >> Furthermore we need to round up the ending addresses here, in order to >> fully cover eventual partial trailing pages. > > Is rounding up the right thing to do? We round down in find_max_pfn()?Yes, it is - we''re trying to determine a new max_page/max_pdx here, so we should include the trailing part of a partial page. This is particularly necessary for the modules, as otherwise the last few bytes of a module may end up being in memory not satisfying mfn_valid(). If anything, we''d need to round down after the E820 loop, and round up after the modules one. But I don''t think the two max_p* being one too big here would matter much, so uniformly rounding up seems sufficient. Jan>> Signed-off-by: Jan Beulich <jbeulich@suse.com> >> >> --- a/xen/arch/x86/setup.c >> +++ b/xen/arch/x86/setup.c >> @@ -1013,9 +1013,17 @@ void __init __start_xen(unsigned long mb >> ASSERT(j); >> } >> map_e = boot_e820.map[j].addr + boot_e820.map[j].size; >> - if ( (map_e >> PAGE_SHIFT) < max_page ) >> + for ( j = 0; j < mbi->mods_count; ++j ) >> { >> - max_page = map_e >> PAGE_SHIFT; >> + uint64_t end = pfn_to_paddr(mod[j].mod_start) + >> + mod[j].mod_end; >> + >> + if ( map_e < end ) >> + map_e = end; >> + } >> + if ( PFN_UP(map_e) < max_page ) >> + { >> + max_page = PFN_UP(map_e); >> max_pdx = pfn_to_pdx(max_page - 1) + 1; >> } >> printk(XENLOG_WARNING "Ignoring inaccessible memory range" >> >> >>
Keir Fraser
2013-Nov-18 12:26 UTC
Re: [PATCH] x86: consider modules when cutting off memory
On 18/11/2013 04:11, "Jan Beulich" <JBeulich@suse.com> wrote:>>>> On 18.11.13 at 12:32, Keir Fraser <keir.xen@gmail.com> wrote: >> On 18/11/2013 00:37, "Jan Beulich" <JBeulich@suse.com> wrote: >> >>> The code in question runs after module ranges got already removed from >>> the E820 table, so when determining the new maximum page/PDX we need to >>> explicitly take them into account. >>> >>> Furthermore we need to round up the ending addresses here, in order to >>> fully cover eventual partial trailing pages. >> >> Is rounding up the right thing to do? We round down in find_max_pfn()? > > Yes, it is - we''re trying to determine a new max_page/max_pdx > here, so we should include the trailing part of a partial page. This > is particularly necessary for the modules, as otherwise the last > few bytes of a module may end up being in memory not satisfying > mfn_valid(). > > If anything, we''d need to round down after the E820 loop, and > round up after the modules one. But I don''t think the two max_p* > being one too big here would matter much, so uniformly rounding > up seems sufficient.Okay makes sense. Acked-by: Keir Fraser <keir@xen.org>> Jan > >>> Signed-off-by: Jan Beulich <jbeulich@suse.com> >>> >>> --- a/xen/arch/x86/setup.c >>> +++ b/xen/arch/x86/setup.c >>> @@ -1013,9 +1013,17 @@ void __init __start_xen(unsigned long mb >>> ASSERT(j); >>> } >>> map_e = boot_e820.map[j].addr + boot_e820.map[j].size; >>> - if ( (map_e >> PAGE_SHIFT) < max_page ) >>> + for ( j = 0; j < mbi->mods_count; ++j ) >>> { >>> - max_page = map_e >> PAGE_SHIFT; >>> + uint64_t end = pfn_to_paddr(mod[j].mod_start) + >>> + mod[j].mod_end; >>> + >>> + if ( map_e < end ) >>> + map_e = end; >>> + } >>> + if ( PFN_UP(map_e) < max_page ) >>> + { >>> + max_page = PFN_UP(map_e); >>> max_pdx = pfn_to_pdx(max_page - 1) + 1; >>> } >>> printk(XENLOG_WARNING "Ignoring inaccessible memory range" >>> >>> >>> > > >