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xen/setup: update VA mapping when releasing memory during setup

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In xen_memory_setup(), if a page that is being released has a VA
mapping this must also be updated.  Otherwise, the page will be not
released completely -- it will still be referenced in Xen and won't be
freed util the mapping is removed and this prevents it from being
reallocated at a different PFN.

This was already being done for the ISA memory region in
xen_ident_map_ISA() but on many systems this was omitting a few pages
as many systems marked a few pages below the ISA memory region as
reserved in the e820 map.

This fixes errors such as:

(XEN) page_alloc.c:1148:d0 Over-allocation for domain 0: 2097153 > 2097152
(XEN) memory.c:133:d0 Could not allocate order=0 extent: id=0 memflags=0 (0 of 17)

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
David Vrabel 2012-05-03 16:15:42 +01:00 committed by Konrad Rzeszutek Wilk
parent 96dc08b35c
commit 83d51ab473
4 changed files with 34 additions and 32 deletions
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1
arch/x86/xen/enlighten.c
View file

@ -1308,7 +1308,6 @@ asmlinkage void __init xen_start_kernel(void)
xen_raw_console_write("mapping kernel into physical memory\n");
pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
xen_ident_map_ISA();
/* Allocate and initialize top and mid mfn levels for p2m structure */
xen_build_mfn_list_list();

23
arch/x86/xen/mmu.c
View file

@ -1929,29 +1929,6 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
#endif
}
void __init xen_ident_map_ISA(void)
{
unsigned long pa;
/*
* If we're dom0, then linear map the ISA machine addresses into
* the kernel's address space.
*/
if (!xen_initial_domain())
return;
xen_raw_printk("Xen: setup ISA identity maps\n");
for (pa = ISA_START_ADDRESS; pa < ISA_END_ADDRESS; pa += PAGE_SIZE) {
pte_t pte = mfn_pte(PFN_DOWN(pa), PAGE_KERNEL_IO);
if (HYPERVISOR_update_va_mapping(PAGE_OFFSET + pa, pte, 0))
BUG();
}
xen_flush_tlb();
}
static void __init xen_post_allocator_init(void)
{
pv_mmu_ops.set_pte = xen_set_pte;

41
arch/x86/xen/setup.c
View file

@ -139,6 +139,13 @@ static unsigned long __init xen_do_chunk(unsigned long start,
return len;
}
static unsigned long __init xen_release_chunk(unsigned long start,
unsigned long end)
{
return xen_do_chunk(start, end, true);
}
static unsigned long __init xen_populate_chunk(
const struct e820entry *list, size_t map_size,
unsigned long max_pfn, unsigned long *last_pfn,
@ -197,6 +204,29 @@ static unsigned long __init xen_populate_chunk(
}
return done;
}
static void __init xen_set_identity_and_release_chunk(
unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
unsigned long *released, unsigned long *identity)
{
unsigned long pfn;
/*
* If the PFNs are currently mapped, the VA mapping also needs
* to be updated to be 1:1.
*/
for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
(void)HYPERVISOR_update_va_mapping(
(unsigned long)__va(pfn << PAGE_SHIFT),
mfn_pte(pfn, PAGE_KERNEL_IO), 0);
if (start_pfn < nr_pages)
*released += xen_release_chunk(
start_pfn, min(end_pfn, nr_pages));
*identity += set_phys_range_identity(start_pfn, end_pfn);
}
static unsigned long __init xen_set_identity_and_release(
const struct e820entry *list, size_t map_size, unsigned long nr_pages)
{
@ -226,14 +256,11 @@ static unsigned long __init xen_set_identity_and_release(
if (entry->type == E820_RAM)
end_pfn = PFN_UP(entry->addr);
if (start_pfn < end_pfn) {
if (start_pfn < nr_pages)
released += xen_do_chunk(
start_pfn, min(end_pfn, nr_pages), true);
if (start_pfn < end_pfn)
xen_set_identity_and_release_chunk(
start_pfn, end_pfn, nr_pages,
&released, &identity);
identity += set_phys_range_identity(
start_pfn, end_pfn);
}
start = end;
}
}

1
arch/x86/xen/xen-ops.h
View file

@ -28,7 +28,6 @@ void xen_setup_shared_info(void);
void xen_build_mfn_list_list(void);
void xen_setup_machphys_mapping(void);
pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn);
void xen_ident_map_ISA(void);
void xen_reserve_top(void);
extern unsigned long xen_max_p2m_pfn;