[PATCH 03/12] xen: map a dummy page for local apic and ioapic in xen_set_fixmap

stefano.stabellini
2010-09-28T12:19:24Z

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
arch/x86/xen/mmu.c | 23 ++++++++++++++++++++---
1 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 42086ac..ffc5e24 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1861,6 +1861,8 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
}
#endif /* CONFIG_X86_64 */

+static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
+
static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
{
pte_t pte;
@@ -1881,15 +1883,28 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
#else
case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
#endif
-#ifdef CONFIG_X86_LOCAL_APIC
- case FIX_APIC_BASE: /* maps dummy local APIC */
-#endif
case FIX_TEXT_POKE0:
case FIX_TEXT_POKE1:
/* All local page mappings */
pte = pfn_pte(phys, prot);
break;

+#ifdef CONFIG_X86_LOCAL_APIC
+ case FIX_APIC_BASE: /* maps dummy local APIC */
+ pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+ break;
+#endif
+
+#ifdef CONFIG_X86_IO_APIC
+ case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
+ /*
+ * We just don't map the IO APIC - all access is via
+ * hypercalls. Keep the address in the pte for reference.
+ */
+ pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+ break;
+#endif
+
case FIX_PARAVIRT_BOOTMAP:
/* This is an MFN, but it isn't an IO mapping from the
IO domain */
@@ -2027,6 +2042,8 @@ void __init xen_init_mmu_ops(void)
pv_mmu_ops = xen_mmu_ops;

vmap_lazy_unmap = false;
+
+ memset(dummy_mapping, 0xff, PAGE_SIZE);
}

/* Protected by xen_reservation_lock. */
--
1.5.6.5