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authorAlex Nixon <alex.nixon@citrix.com>2010-02-19 13:31:06 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2010-06-07 14:33:13 -0400
commit7347b4082e55ac4a673f06a0a0ce25c37273c9ec (patch)
treeb39ef6d8aaf3081b97a12fa06ca86ffb668d1b68 /arch/x86/xen/mmu.c
parentc0011dbfce69467b23b08fb4a64c39a409a935fb (diff)
downloadlinux-linaro-android-7347b4082e55ac4a673f06a0a0ce25c37273c9ec.tar.gz
xen: Allow unprivileged Xen domains to create iomap pages
PV DomU domains are allowed to map hardware MFNs for PCI passthrough, but are not generally allowed to map raw machine pages. In particular, various pieces of code try to map DMI and ACPI tables in the ISA ROM range. We disallow _PAGE_IOMAP for those mappings, so that they are redirected to a set of local zeroed pages we reserve for that purpose. [ Impact: prevent passthrough of ISA space, as we only allow PCI ] Signed-off-by: Alex Nixon <alex.nixon@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch/x86/xen/mmu.c')
-rw-r--r--arch/x86/xen/mmu.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index a4dea9df0cc..a5577f59416 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -51,6 +51,7 @@
#include <asm/mmu_context.h>
#include <asm/setup.h>
#include <asm/paravirt.h>
+#include <asm/e820.h>
#include <asm/linkage.h>
#include <asm/xen/hypercall.h>
@@ -381,7 +382,7 @@ static bool xen_page_pinned(void *ptr)
static bool xen_iomap_pte(pte_t pte)
{
- return xen_initial_domain() && (pte_flags(pte) & _PAGE_IOMAP);
+ return pte_flags(pte) & _PAGE_IOMAP;
}
static void xen_set_iomap_pte(pte_t *ptep, pte_t pteval)
@@ -583,10 +584,21 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
pte_t xen_make_pte(pteval_t pte)
{
- if (unlikely(xen_initial_domain() && (pte & _PAGE_IOMAP)))
+ phys_addr_t addr = (pte & PTE_PFN_MASK);
+
+ /*
+ * Unprivileged domains are allowed to do IOMAPpings for
+ * PCI passthrough, but not map ISA space. The ISA
+ * mappings are just dummy local mappings to keep other
+ * parts of the kernel happy.
+ */
+ if (unlikely(pte & _PAGE_IOMAP) &&
+ (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
pte = iomap_pte(pte);
- else
+ } else {
+ pte &= ~_PAGE_IOMAP;
pte = pte_pfn_to_mfn(pte);
+ }
return native_make_pte(pte);
}