Re: [PATCH] x86: extend e820 ealy_res support 32bit - fix #2

[Jeremy Fitzhardinge]

Yinghai Lu wrote:
> On Thu, May 29, 2008 at 11:52 AM, Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
>   
> > On Thu, May 29, 2008 at 6:37 AM, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
> >     
> > > Yinghai Lu wrote:
> > >       
> > > > can we use e820 entries for that? So the domain builder could have
> > > > several entries for E820_RAM and E820_RESERVED...
> > > >
> > > >         
> > > I tried this, but it doesn't work; the kernel crashes during boot,
> > > presumably because it's trying to use the reserved memory as heap.  I
> > > suspect the e820 maps are not registered early enough or something...
> > >
> > > (One thought: if reserving in the E820 map were enough, then couldn't we use
> > > it for all the early reservations?)
> > >
> > > I've attached the non-working patch below.
> > >
> > > The working kernel reports:
> > >
> > > (early) BIOS-provided physical RAM map:
> > > (early)  Xen: 0000000000000000 - 000000000009f000 (usable)
> > > (early)  Xen: 0000000000100000 - 0000000010000000 (usable)
> > > (early) console [xenboot0] enabled
> > > (early) debug: ignoring loglevel setting.
> > > (early) 0MB HIGHMEM available.
> > > (early) 256MB LOWMEM available.
> > > (early)   low ram: 018fd000 - 10000000
> > > (early)   bootmap 018fd000 - 018ff000
> > > (early)   early res: 0 [0-fff] BIOS data page
> > > (early)   early res: 1 [1000-1fff] EX TRAMPOLINE
> > > (early)   early res: 2 [6000-6fff] TRAMPOLINE
> > > (early)   early res: 3 [18aa000-18ecfff] XEN
> > > (early)   early res: 4 [1000000-18a9303] TEXT DATA BSS
> > > (early)   early res: 5 [18ed000-18fcfff] INIT_PG_TABLE
> > > (early)   early res: 6 [18fd000-18fefff] BOOTMAP
> > >
> > > But the non-working one says:
> > >
> > > (early) BIOS-provided physical RAM map:
> > > (early)  Xen: 0000000000000000 - 000000000009f000 (usable)
> > > (early)  Xen: 0000000000100000 - 0000000010000000 (usable)
> > > (early)  Xen: 00000000018aa000 - 00000000018ed000 (reserved)
> > >       
> > it seems we miss to call sanitize_e820_map for 32 bit. we should get
> > (early)  Xen: 0000000000000000 - 000000000009f000 (usable)
> > (early)  Xen: 0000000000100000 - 00000000018aa000 (usable)
> > (early)  Xen: 00000000018aa000 - 00000000018ed000 (reserved)
> > (early)  Xen: 00000000018ed000 - 0000000010000000 (usable)
> >     
>
> xen pv override the memory_setup. and default one is
> machine_specific_memory_setup(), and it does call sanitize_e820_map...
>
> so you may need to add sanitize_e820_map to xen_memory_setup, or re
> arrange your add_memory_range parameter...

Yes, adding

       sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

after the Xen reservation made everything happy.

   J

Subject: xen: reserve Xen-specific memory in e820 map

Make sure that the start_info and pfn->mfn translation array are reserved.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
arch/x86/xen/setup.c |   13 +++++++++++++
1 file changed, 13 insertions(+)

===================================================================
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -40,8 +40,21 @@
	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);

	e820.nr_map = 0;
+
	add_memory_region(0, LOWMEMSIZE(), E820_RAM);
	add_memory_region(HIGH_MEMORY, PFN_PHYS(max_pfn)-HIGH_MEMORY, E820_RAM);
+
+	/*
+	 * Reserve Xen bits:
+	 *  - mfn_list
+	 *  - xen_start_info
+	 * See comment above "struct start_info" in <xen/interface/xen.h>
+	 */
+	add_memory_region(__pa(xen_start_info->mfn_list),
+			  xen_start_info->pt_base - xen_start_info->mfn_list,
+			  E820_RESERVED);
+
+	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

	return "Xen";
}


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