[PATCH 06/12] xen: add the direct mapping area for ISA bus access

stefano.stabellini
2010-09-28T12:18:42Z

From: Juan Quintela <quintela@redhat.com>

add the direct mapping area for ISA bus access when running as initial
domain

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
arch/x86/xen/enlighten.c | 1 +
arch/x86/xen/mmu.c | 24 ++++++++++++++++++++++++
arch/x86/xen/setup.c | 3 +++
3 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 1ccfa1b..9efb004 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1186,6 +1186,7 @@ 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();

init_mm.pgd = pgd;

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index ffc5e24..eed9c7c 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1682,6 +1682,7 @@ static void *m2v(phys_addr_t maddr)
return __ka(m2p(maddr));
}

+/* Set the page permissions on an identity-mapped pages */
static void set_page_prot(void *addr, pgprot_t prot)
{
unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
@@ -1929,6 +1930,29 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
#endif
}

+__init void 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 __init void xen_post_allocator_init(void)
{
pv_mmu_ops.set_pte = xen_set_pte;
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index c413132..62ceb78 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -119,6 +119,9 @@ char * __init xen_memory_setup(void)
* Even though this is normal, usable memory under Xen, reserve
* ISA memory anyway because too many things think they can poke
* about in there.
+ *
+ * In a dom0 kernel, this region is identity mapped with the
+ * hardware ISA area, so it really is out of bounds.
*/
e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
E820_RESERVED);
--
1.5.6.5