xen/grant-table: Refactor gnttab_[un]map_refs to avoid m2p_override
The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
for blkback and future netback patches it just cause a lock contention, as
those pages never go to userspace. Therefore this series does the following:
- the bulk of the original function (everything after the mapping hypercall)
is moved to arch-dependent set/clear_foreign_p2m_mapping
- the "if (xen_feature(XENFEAT_auto_translated_physmap))" branch goes to ARM
- therefore the ARM function could be much smaller, the m2p_override stubs
could be also removed
- on x86 the set_phys_to_machine calls were moved up to this new funcion
from m2p_override functions
- and m2p_override functions are only called when there is a kmap_ops param
It also removes a stray space from arch/x86/include/asm/xen/page.h.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: Anthony Liguori <aliguori@amazon.com>
Suggested-by: David Vrabel <david.vrabel@citrix.com>
Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index b84e3ab..6d325bd 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -933,9 +933,6 @@
struct page **pages, unsigned int count)
{
int i, ret;
- bool lazy = false;
- pte_t *pte;
- unsigned long mfn;
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
if (ret)
@@ -947,45 +944,7 @@
gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
&map_ops[i].status, __func__);
- /* this is basically a nop on x86 */
- if (xen_feature(XENFEAT_auto_translated_physmap)) {
- for (i = 0; i < count; i++) {
- if (map_ops[i].status)
- continue;
- set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
- map_ops[i].dev_bus_addr >> PAGE_SHIFT);
- }
- return ret;
- }
-
- if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
- arch_enter_lazy_mmu_mode();
- lazy = true;
- }
-
- for (i = 0; i < count; i++) {
- /* Do not add to override if the map failed. */
- if (map_ops[i].status)
- continue;
-
- if (map_ops[i].flags & GNTMAP_contains_pte) {
- pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
- (map_ops[i].host_addr & ~PAGE_MASK));
- mfn = pte_mfn(*pte);
- } else {
- mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
- }
- ret = m2p_add_override(mfn, pages[i], kmap_ops ?
- &kmap_ops[i] : NULL);
- if (ret)
- goto out;
- }
-
- out:
- if (lazy)
- arch_leave_lazy_mmu_mode();
-
- return ret;
+ return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
}
EXPORT_SYMBOL_GPL(gnttab_map_refs);
@@ -993,39 +952,13 @@
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count)
{
- int i, ret;
- bool lazy = false;
+ int ret;
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
if (ret)
return ret;
- /* this is basically a nop on x86 */
- if (xen_feature(XENFEAT_auto_translated_physmap)) {
- for (i = 0; i < count; i++) {
- set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
- INVALID_P2M_ENTRY);
- }
- return ret;
- }
-
- if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
- arch_enter_lazy_mmu_mode();
- lazy = true;
- }
-
- for (i = 0; i < count; i++) {
- ret = m2p_remove_override(pages[i], kmap_ops ?
- &kmap_ops[i] : NULL);
- if (ret)
- goto out;
- }
-
- out:
- if (lazy)
- arch_leave_lazy_mmu_mode();
-
- return ret;
+ return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count);
}
EXPORT_SYMBOL_GPL(gnttab_unmap_refs);