Merge tag 'for-linus-4.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull xen fixes from Juergen Gross:
 "This contains two fixes for running under Xen:

   - a fix avoiding resource conflicts between adding mmio areas and
     memory hotplug

   - a fix setting NX bits in page table entries copied from Xen when
     running a PV guest"

* tag 'for-linus-4.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: Mark unallocated host memory as UNUSABLE
  x86-64/Xen: eliminate W+X mappings

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index d669e9d..c9081c6 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1,8 +1,12 @@
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+#include <linux/bootmem.h>
+#endif
 #include <linux/cpu.h>
 #include <linux/kexec.h>
 
 #include <xen/features.h>
 #include <xen/page.h>
+#include <xen/interface/memory.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
@@ -331,3 +335,80 @@ void xen_arch_unregister_cpu(int num)
 }
 EXPORT_SYMBOL(xen_arch_unregister_cpu);
 #endif
+
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+void __init arch_xen_balloon_init(struct resource *hostmem_resource)
+{
+       struct xen_memory_map memmap;
+       int rc;
+       unsigned int i, last_guest_ram;
+       phys_addr_t max_addr = PFN_PHYS(max_pfn);
+       struct e820_table *xen_e820_table;
+       const struct e820_entry *entry;
+       struct resource *res;
+
+       if (!xen_initial_domain())
+               return;
+
+       xen_e820_table = kmalloc(sizeof(*xen_e820_table), GFP_KERNEL);
+       if (!xen_e820_table)
+               return;
+
+       memmap.nr_entries = ARRAY_SIZE(xen_e820_table->entries);
+       set_xen_guest_handle(memmap.buffer, xen_e820_table->entries);
+       rc = HYPERVISOR_memory_op(XENMEM_machine_memory_map, &memmap);
+       if (rc) {
+               pr_warn("%s: Can't read host e820 (%d)\n", __func__, rc);
+               goto out;
+       }
+
+       last_guest_ram = 0;
+       for (i = 0; i < memmap.nr_entries; i++) {
+               if (xen_e820_table->entries[i].addr >= max_addr)
+                       break;
+               if (xen_e820_table->entries[i].type == E820_TYPE_RAM)
+                       last_guest_ram = i;
+       }
+
+       entry = &xen_e820_table->entries[last_guest_ram];
+       if (max_addr >= entry->addr + entry->size)
+               goto out; /* No unallocated host RAM. */
+
+       hostmem_resource->start = max_addr;
+       hostmem_resource->end = entry->addr + entry->size;
+
+       /*
+        * Mark non-RAM regions between the end of dom0 RAM and end of host RAM
+        * as unavailable. The rest of that region can be used for hotplug-based
+        * ballooning.
+        */
+       for (; i < memmap.nr_entries; i++) {
+               entry = &xen_e820_table->entries[i];
+
+               if (entry->type == E820_TYPE_RAM)
+                       continue;
+
+               if (entry->addr >= hostmem_resource->end)
+                       break;
+
+               res = kzalloc(sizeof(*res), GFP_KERNEL);
+               if (!res)
+                       goto out;
+
+               res->name = "Unavailable host RAM";
+               res->start = entry->addr;
+               res->end = (entry->addr + entry->size < hostmem_resource->end) ?
+                           entry->addr + entry->size : hostmem_resource->end;
+               rc = insert_resource(hostmem_resource, res);
+               if (rc) {
+                       pr_warn("%s: Can't insert [%llx - %llx) (%d)\n",
+                               __func__, res->start, res->end, rc);
+                       kfree(res);
+                       goto  out;
+               }
+       }
+
+ out:
+       kfree(xen_e820_table);
+}
+#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 7beeee1..c047f42 100644 (file)
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -88,6 +88,8 @@
 #include "multicalls.h"
 #include "pmu.h"
 
+#include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
+
 void *xen_initial_gdt;
 
 static int xen_cpu_up_prepare_pv(unsigned int cpu);
@@ -1258,6 +1260,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
        __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
 
        /* Work out if we support NX */
+       get_cpu_cap(&boot_cpu_data);
        x86_configure_nx();
 
        /* Get mfn list */

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 6cf801c..69145ea 100644 (file)
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -1902,6 +1902,18 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
        /* Graft it onto L4[511][510] */
        copy_page(level2_kernel_pgt, l2);
 
+       /*
+        * Zap execute permission from the ident map. Due to the sharing of
+        * L1 entries we need to do this in the L2.
+        */
+       if (__supported_pte_mask & _PAGE_NX) {
+               for (i = 0; i < PTRS_PER_PMD; ++i) {
+                       if (pmd_none(level2_ident_pgt[i]))
+                               continue;
+                       level2_ident_pgt[i] = pmd_set_flags(level2_ident_pgt[i], _PAGE_NX);
+               }
+       }
+
        /* Copy the initial P->M table mappings if necessary. */
        i = pgd_index(xen_start_info->mfn_list);
        if (i && i < pgd_index(__START_KERNEL_map))

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index c114ca7..6e0d208 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -808,7 +808,6 @@ char * __init xen_memory_setup(void)
        addr = xen_e820_table.entries[0].addr;
        size = xen_e820_table.entries[0].size;
        while (i < xen_e820_table.nr_entries) {
-               bool discard = false;
 
                chunk_size = size;
                type = xen_e820_table.entries[i].type;
@@ -824,11 +823,10 @@ char * __init xen_memory_setup(void)
                                xen_add_extra_mem(pfn_s, n_pfns);
                                xen_max_p2m_pfn = pfn_s + n_pfns;
                        } else
-                               discard = true;
+                               type = E820_TYPE_UNUSABLE;
                }
 
-               if (!discard)
-                       xen_align_and_add_e820_region(addr, chunk_size, type);
+               xen_align_and_add_e820_region(addr, chunk_size, type);
 
                addr += chunk_size;
                size -= chunk_size;

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index f77e499..065f0b6 100644 (file)
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -257,10 +257,25 @@ static void release_memory_resource(struct resource *resource)
        kfree(resource);
 }
 
+/*
+ * Host memory not allocated to dom0. We can use this range for hotplug-based
+ * ballooning.
+ *
+ * It's a type-less resource. Setting IORESOURCE_MEM will make resource
+ * management algorithms (arch_remove_reservations()) look into guest e820,
+ * which we don't want.
+ */
+static struct resource hostmem_resource = {
+       .name   = "Host RAM",
+};
+
+void __attribute__((weak)) __init arch_xen_balloon_init(struct resource *res)
+{}
+
 static struct resource *additional_memory_resource(phys_addr_t size)
 {
-       struct resource *res;
-       int ret;
+       struct resource *res, *res_hostmem;
+       int ret = -ENOMEM;
 
        res = kzalloc(sizeof(*res), GFP_KERNEL);
        if (!res)
@@ -269,13 +284,42 @@ static struct resource *additional_memory_resource(phys_addr_t size)
        res->name = "System RAM";
        res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 
-       ret = allocate_resource(&iomem_resource, res,
-                               size, 0, -1,
-                               PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
-       if (ret < 0) {
-               pr_err("Cannot allocate new System RAM resource\n");
-               kfree(res);
-               return NULL;
+       res_hostmem = kzalloc(sizeof(*res), GFP_KERNEL);
+       if (res_hostmem) {
+               /* Try to grab a range from hostmem */
+               res_hostmem->name = "Host memory";
+               ret = allocate_resource(&hostmem_resource, res_hostmem,
+                                       size, 0, -1,
+                                       PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
+       }
+
+       if (!ret) {
+               /*
+                * Insert this resource into iomem. Because hostmem_resource
+                * tracks portion of guest e820 marked as UNUSABLE noone else
+                * should try to use it.
+                */
+               res->start = res_hostmem->start;
+               res->end = res_hostmem->end;
+               ret = insert_resource(&iomem_resource, res);
+               if (ret < 0) {
+                       pr_err("Can't insert iomem_resource [%llx - %llx]\n",
+                               res->start, res->end);
+                       release_memory_resource(res_hostmem);
+                       res_hostmem = NULL;
+                       res->start = res->end = 0;
+               }
+       }
+
+       if (ret) {
+               ret = allocate_resource(&iomem_resource, res,
+                                       size, 0, -1,
+                                       PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
+               if (ret < 0) {
+                       pr_err("Cannot allocate new System RAM resource\n");
+                       kfree(res);
+                       return NULL;
+               }
        }
 
 #ifdef CONFIG_SPARSEMEM
@@ -287,6 +331,7 @@ static struct resource *additional_memory_resource(phys_addr_t size)
                        pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n",
                               pfn, limit);
                        release_memory_resource(res);
+                       release_memory_resource(res_hostmem);
                        return NULL;
                }
        }
@@ -765,6 +810,8 @@ static int __init balloon_init(void)
        set_online_page_callback(&xen_online_page);
        register_memory_notifier(&xen_memory_nb);
        register_sysctl_table(xen_root);
+
+       arch_xen_balloon_init(&hostmem_resource);
 #endif
 
 #ifdef CONFIG_XEN_PV

diff --git a/include/xen/balloon.h b/include/xen/balloon.h
index 4914b93..61f410f 100644 (file)
--- a/include/xen/balloon.h
+++ b/include/xen/balloon.h
@@ -44,3 +44,8 @@ static inline void xen_balloon_init(void)
 {
 }
 #endif
+
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+struct resource;
+void arch_xen_balloon_init(struct resource *hostmem_resource);
+#endif