[Xen-devel] [GIT PULL] Small Xen bugfixes

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

 Hi Linus,

Here are some small Xen bugfixes:

    * fix dom0 boot on systems whose E820 doesn't completely cover the
      ISA address space.  This fixes a crash on a Dell R310.
    * fix misallocation of initial pagetables on 32-bit systems
      (sizeof(pmd_t) != sizeof(pmd_t *)).  In practice this didn't cause
      a problem because the following allocation was page-aligned so the
      padding was big enough to make up the difference.
    * in xenfs, properly report put_user failures to write back error status

The changes are on two branches:

  git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git upstream/core

Ian Campbell (2):
      xen: do not release any memory under 1M in domain 0
      xen: correct size of level2_kernel_pgt

 arch/x86/xen/mmu.c   |    2 +-
 arch/x86/xen/setup.c |   31 ++++++++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)

  git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git upstream/xenfs

Vasiliy Kulikov (1):
      xen: xenfs: privcmd: check put_user() return code

 drivers/xen/xenfs/privcmd.c |    8 ++------
 1 files changed, 2 insertions(+), 6 deletions(-)

Thanks,
        J


diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index e41683c..13cd4eb 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2104,7 +2104,7 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
 {
        pmd_t *kernel_pmd;
 
-       level2_kernel_pgt = extend_brk(sizeof(pmd_t *) * PTRS_PER_PMD, 
PAGE_SIZE);
+       level2_kernel_pgt = extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
 
        max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
                                  xen_start_info->nr_pt_frames * PAGE_SIZE +
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 8e2c9f21..1f49951 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -84,6 +84,22 @@ static unsigned long __init xen_release_chunk(phys_addr_t 
start_addr,
        start = PFN_UP(start_addr);
        end = PFN_DOWN(end_addr);
 
+       /*
+        * Domain 0 maintains a 1-1 P2M mapping for the first megabyte
+        * so do not return such memory to the hypervisor.
+        *
+        * This region can contain various firmware tables and the
+        * like which are often assumed to be always mapped and
+        * available via phys_to_virt.
+        */
+       if (xen_initial_domain()) {
+               if (end < PFN_DOWN(ISA_END_ADDRESS))
+                       return 0;
+
+               if (start < PFN_DOWN(ISA_END_ADDRESS))
+                       start = PFN_DOWN(ISA_END_ADDRESS);
+       }
+
        if (end <= start)
                return 0;
 
@@ -163,6 +179,7 @@ char * __init xen_memory_setup(void)
                XENMEM_memory_map;
        rc = HYPERVISOR_memory_op(op, &memmap);
        if (rc == -ENOSYS) {
+               BUG_ON(xen_initial_domain());
                memmap.nr_entries = 1;
                map[0].addr = 0ULL;
                map[0].size = mem_end;
@@ -200,12 +217,16 @@ 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.
+        * Even though this is normal, usable memory in a Xen domU,
+        * reserve ISA memory anyway because too many things think
+        * they can poke about in there.
+        *
+        * In dom0 we use the host e820 and therefore do not need to
+        * specially reserved anything.
         */
-       e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
-                       E820_RESERVED);
+       if (!xen_initial_domain())
+               e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - 
ISA_START_ADDRESS,
+                               E820_RESERVED);
 
        /*
         * Reserve Xen bits:
diff --git a/drivers/xen/xenfs/privcmd.c b/drivers/xen/xenfs/privcmd.c
index f80be7f..2eb04c8 100644
--- a/drivers/xen/xenfs/privcmd.c
+++ b/drivers/xen/xenfs/privcmd.c
@@ -266,9 +266,7 @@ static int mmap_return_errors(void *data, void *state)
        xen_pfn_t *mfnp = data;
        struct mmap_batch_state *st = state;
 
-       put_user(*mfnp, st->user++);
-
-       return 0;
+       return put_user(*mfnp, st->user++);
 }
 
 static struct vm_operations_struct privcmd_vm_ops;
@@ -323,10 +321,8 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
        up_write(&mm->mmap_sem);
 
        if (state.err > 0) {
-               ret = 0;
-
                state.user = m.arr;
-               traverse_pages(m.num, sizeof(xen_pfn_t),
+               ret = traverse_pages(m.num, sizeof(xen_pfn_t),
                               &pagelist,
                               mmap_return_errors, &state);
        }



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