[Xen-devel] [PATCH v5 1/6] xen/arm: remove handling of XENFEAT_grant_map_identity

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

The feature has been removed from Xen. Also Linux cannot use it on ARM32
without CONFIG_ARM_LPAE.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

---
Changes in v2:

- remove the definition of XENFEAT_grant_map_identity.
---
 arch/arm/xen/enlighten.c         |    5 ---
 arch/arm/xen/mm32.c              |   85 +-------------------------------------
 include/xen/interface/features.h |    3 --
 3 files changed, 1 insertion(+), 92 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 0e15f01..c7ca936 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -261,11 +261,6 @@ static int __init xen_guest_init(void)
 
        xen_setup_features();
 
-       if (!xen_feature(XENFEAT_grant_map_identity)) {
-               pr_warn("Please upgrade your Xen.\n"
-                               "If your platform has any non-coherent DMA 
devices, they won't work properly.\n");
-       }
-
        if (xen_feature(XENFEAT_dom0))
                xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
        else
diff --git a/arch/arm/xen/mm32.c b/arch/arm/xen/mm32.c
index 3b99860..a5a93fc 100644
--- a/arch/arm/xen/mm32.c
+++ b/arch/arm/xen/mm32.c
@@ -5,70 +5,6 @@
 
 #include <xen/features.h>
 
-static DEFINE_PER_CPU(unsigned long, xen_mm32_scratch_virt);
-static DEFINE_PER_CPU(pte_t *, xen_mm32_scratch_ptep);
-
-static int alloc_xen_mm32_scratch_page(int cpu)
-{
-       struct page *page;
-       unsigned long virt;
-       pmd_t *pmdp;
-       pte_t *ptep;
-
-       if (per_cpu(xen_mm32_scratch_ptep, cpu) != NULL)
-               return 0;
-
-       page = alloc_page(GFP_KERNEL);
-       if (page == NULL) {
-               pr_warn("Failed to allocate xen_mm32_scratch_page for cpu 
%d\n", cpu);
-               return -ENOMEM;
-       }
-
-       virt = (unsigned long)__va(page_to_phys(page));
-       pmdp = pmd_offset(pud_offset(pgd_offset_k(virt), virt), virt);
-       ptep = pte_offset_kernel(pmdp, virt);
-
-       per_cpu(xen_mm32_scratch_virt, cpu) = virt;
-       per_cpu(xen_mm32_scratch_ptep, cpu) = ptep;
-
-       return 0;
-}
-
-static int xen_mm32_cpu_notify(struct notifier_block *self,
-                                   unsigned long action, void *hcpu)
-{
-       int cpu = (long)hcpu;
-       switch (action) {
-       case CPU_UP_PREPARE:
-               if (alloc_xen_mm32_scratch_page(cpu))
-                       return NOTIFY_BAD;
-               break;
-       default:
-               break;
-       }
-       return NOTIFY_OK;
-}
-
-static struct notifier_block xen_mm32_cpu_notifier = {
-       .notifier_call  = xen_mm32_cpu_notify,
-};
-
-static void* xen_mm32_remap_page(dma_addr_t handle)
-{
-       unsigned long virt = get_cpu_var(xen_mm32_scratch_virt);
-       pte_t *ptep = __get_cpu_var(xen_mm32_scratch_ptep);
-
-       *ptep = pfn_pte(handle >> PAGE_SHIFT, PAGE_KERNEL);
-       local_flush_tlb_kernel_page(virt);
-
-       return (void*)virt;
-}
-
-static void xen_mm32_unmap(void *vaddr)
-{
-       put_cpu_var(xen_mm32_scratch_virt);
-}
-
 
 /* functions called by SWIOTLB */
 
@@ -88,13 +24,7 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long 
offset,
        
                if (!pfn_valid(pfn))
                {
-                       /* Cannot map the page, we don't know its physical 
address.
-                        * Return and hope for the best */
-                       if (!xen_feature(XENFEAT_grant_map_identity))
-                               return;
-                       vaddr = xen_mm32_remap_page(handle) + offset;
-                       op(vaddr, len, dir);
-                       xen_mm32_unmap(vaddr - offset);
+                       /* TODO: cache flush */
                } else {
                        struct page *page = pfn_to_page(pfn);
 
@@ -181,22 +111,9 @@ void xen_dma_sync_single_for_device(struct device *hwdev,
 
 int __init xen_mm32_init(void)
 {
-       int cpu;
-
        if (!xen_initial_domain())
                return 0;
 
-       register_cpu_notifier(&xen_mm32_cpu_notifier);
-       get_online_cpus();
-       for_each_online_cpu(cpu) {
-               if (alloc_xen_mm32_scratch_page(cpu)) {
-                       put_online_cpus();
-                       unregister_cpu_notifier(&xen_mm32_cpu_notifier);
-                       return -ENOMEM;
-               }
-       }
-       put_online_cpus();
-
        return 0;
 }
 arch_initcall(xen_mm32_init);
diff --git a/include/xen/interface/features.h b/include/xen/interface/features.h
index 14334d0..131a6cc 100644
--- a/include/xen/interface/features.h
+++ b/include/xen/interface/features.h
@@ -53,9 +53,6 @@
 /* operation as Dom0 is supported */
 #define XENFEAT_dom0                      11
 
-/* Xen also maps grant references at pfn = mfn */
-#define XENFEAT_grant_map_identity        12
-
 #define XENFEAT_NR_SUBMAPS 1
 
 #endif /* __XEN_PUBLIC_FEATURES_H__ */
-- 
1.7.10.4


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