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Subject[PATCH 03/16] xen dom0: Set up basic IO permissions for dom0.
Date
From: Juan Quintela <quintela@redhat.com>

Add the direct mapping area for ISA bus access, and enable IO space
access for the guest when running as dom0.

[ Impact: set iopl for dom0 kernel; map ISA ]

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
arch/x86/xen/enlighten.c | 8 ++++++++
arch/x86/xen/mmu.c | 24 ++++++++++++++++++++++++
arch/x86/xen/setup.c | 6 +++++-
arch/x86/xen/xen-ops.h | 1 +
4 files changed, 38 insertions(+), 1 deletions(-)
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 0a1700a..50580fc 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1045,6 +1045,7 @@ 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;

@@ -1054,6 +1055,13 @@ asmlinkage void __init xen_start_kernel(void)
if (xen_feature(XENFEAT_supervisor_mode_kernel))
pv_info.kernel_rpl = 0;

+ if (xen_initial_domain()) {
+ struct physdev_set_iopl set_iopl;
+ set_iopl.iopl = 1;
+ if (HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl) == -1)
+ BUG();
+ }
+
/* set the limit of our address space */
xen_reserve_top();

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 760e3a5..dc840ed 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1615,6 +1615,7 @@ 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;
@@ -1840,6 +1841,29 @@ 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();
+}
+
__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 ad0047f..dc55171 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -51,6 +51,9 @@ 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);
@@ -188,7 +191,8 @@ void __init xen_arch_setup(void)

pm_idle = xen_idle;

- paravirt_disable_iospace();
+ if (!xen_initial_domain())
+ paravirt_disable_iospace();

fiddle_vdso();
}
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 5c50a10..6ff6203 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -29,6 +29,7 @@ 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);
+void xen_ident_map_ISA(void);

void xen_post_allocator_init(void);

--
1.6.0.6


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