From: Julien Grall <julien.grall@arm.com>
The current implementation of setup_xenheap_mappings() is using 1GB
mappings. This can lead to unexpected result because the mapping
may alias a non-cachable region (such as device or reserved regions).
For more details see B2.8 in ARM DDI 0487H.a.
map_pages_to_xen() was recently reworked to allow superpage mappings,
support contiguous mapping and deal with the use of pagge-tables before
they are mapped.
Most of the code in setup_xenheap_mappings() is now replaced with a
single call to map_pages_to_xen().
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Julien Grall <jgrall@amazon.com>
---
Changes in v3:
- Don't use 1GB mapping
- Re-order code in setup_mm() in a separate patch
Changes in v2:
- New patch
---
xen/arch/arm/mm.c | 87 ++++++++++-------------------------------------
1 file changed, 18 insertions(+), 69 deletions(-)
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 11b6b60a2bc1..4af59375d998 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -138,17 +138,6 @@ static DEFINE_PAGE_TABLE(cpu0_pgtable);
static DEFINE_PAGE_TABLES(cpu0_dommap, DOMHEAP_SECOND_PAGES);
#endif
-#ifdef CONFIG_ARM_64
-/* The first page of the first level mapping of the xenheap. The
- * subsequent xenheap first level pages are dynamically allocated, but
- * we need this one to bootstrap ourselves. */
-static DEFINE_PAGE_TABLE(xenheap_first_first);
-/* The zeroeth level slot which uses xenheap_first_first. Used because
- * setup_xenheap_mappings otherwise relies on mfn_to_virt which isn't
- * valid for a non-xenheap mapping. */
-static __initdata int xenheap_first_first_slot = -1;
-#endif
-
/* Common pagetable leaves */
/* Second level page tables.
*
@@ -815,77 +804,37 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
void __init setup_xenheap_mappings(unsigned long base_mfn,
unsigned long nr_mfns)
{
- lpae_t *first, pte;
- unsigned long mfn, end_mfn;
- vaddr_t vaddr;
-
- /* Align to previous 1GB boundary */
- mfn = base_mfn & ~((FIRST_SIZE>>PAGE_SHIFT)-1);
+ int rc;
/* First call sets the xenheap physical and virtual offset. */
if ( mfn_eq(xenheap_mfn_start, INVALID_MFN) )
{
+ unsigned long mfn_gb = base_mfn & ~((FIRST_SIZE >> PAGE_SHIFT) - 1);
+
xenheap_mfn_start = _mfn(base_mfn);
xenheap_base_pdx = mfn_to_pdx(_mfn(base_mfn));
+ /*
+ * The base address may not be aligned to the first level
+ * size (e.g. 1GB when using 4KB pages). This would prevent
+ * superpage mappings for all the regions because the virtual
+ * address and machine address should both be suitably aligned.
+ *
+ * Prevent that by offsetting the start of the xenheap virtual
+ * address.
+ */
xenheap_virt_start = DIRECTMAP_VIRT_START +
- (base_mfn - mfn) * PAGE_SIZE;
+ (base_mfn - mfn_gb) * PAGE_SIZE;
}
if ( base_mfn < mfn_x(xenheap_mfn_start) )
panic("cannot add xenheap mapping at %lx below heap start %lx\n",
base_mfn, mfn_x(xenheap_mfn_start));
- end_mfn = base_mfn + nr_mfns;
-
- /*
- * Virtual address aligned to previous 1GB to match physical
- * address alignment done above.
- */
- vaddr = (vaddr_t)__mfn_to_virt(base_mfn) & FIRST_MASK;
-
- while ( mfn < end_mfn )
- {
- int slot = zeroeth_table_offset(vaddr);
- lpae_t *p = &xen_pgtable[slot];
-
- if ( p->pt.valid )
- {
- /* mfn_to_virt is not valid on the 1st 1st mfn, since it
- * is not within the xenheap. */
- first = slot == xenheap_first_first_slot ?
- xenheap_first_first : mfn_to_virt(lpae_get_mfn(*p));
- }
- else if ( xenheap_first_first_slot == -1)
- {
- /* Use xenheap_first_first to bootstrap the mappings */
- first = xenheap_first_first;
-
- pte = pte_of_xenaddr((vaddr_t)xenheap_first_first);
- pte.pt.table = 1;
- write_pte(p, pte);
-
- xenheap_first_first_slot = slot;
- }
- else
- {
- mfn_t first_mfn = alloc_boot_pages(1, 1);
-
- clear_page(mfn_to_virt(first_mfn));
- pte = mfn_to_xen_entry(first_mfn, MT_NORMAL);
- pte.pt.table = 1;
- write_pte(p, pte);
- first = mfn_to_virt(first_mfn);
- }
-
- pte = mfn_to_xen_entry(_mfn(mfn), MT_NORMAL);
- /* TODO: Set pte.pt.contig when appropriate. */
- write_pte(&first[first_table_offset(vaddr)], pte);
-
- mfn += FIRST_SIZE>>PAGE_SHIFT;
- vaddr += FIRST_SIZE;
- }
-
- flush_xen_tlb_local();
+ rc = map_pages_to_xen((vaddr_t)__mfn_to_virt(base_mfn),
+ _mfn(base_mfn), nr_mfns,
+ PAGE_HYPERVISOR_RW | _PAGE_BLOCK);
+ if ( rc )
+ panic("Unable to setup the xenheap mappings.\n");
}
#endif
--
2.32.0