[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [RFC PATCH 68/84] page_alloc: actually do the mapping and unmapping on xenheap.



Hi,

NIT Title: Please remove full stop.

On 9/26/19 10:46 AM, hongyax@xxxxxxxxxx wrote:
From: Hongyan Xia <hongyax@xxxxxxxxxx>

Please provide a description of what/why you are doing this in the commit message.

Also, IIRC, x86 always have !CONFIG_SEPARATE_XENHEAP. So can you explain why the path with separate xenheap is also modified?


Signed-off-by: Hongyan Xia <hongyax@xxxxxxxxxx>
---
  xen/common/page_alloc.c | 18 ++++++++++++++++--
  1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 7cb1bd368b..4ec6299ba8 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -2143,6 +2143,7 @@ void init_xenheap_pages(paddr_t ps, paddr_t pe)
  void *alloc_xenheap_pages(unsigned int order, unsigned int memflags)
  {
      struct page_info *pg;
+    void *ret;
ASSERT(!in_irq()); @@ -2151,7 +2152,10 @@ void *alloc_xenheap_pages(unsigned int order, unsigned int memflags)
      if ( unlikely(pg == NULL) )
          return NULL;
- memguard_unguard_range(page_to_virt(pg), 1 << (order + PAGE_SHIFT));
+    ret = page_to_virt(pg);
+    memguard_unguard_range(ret, 1 << (order + PAGE_SHIFT));
+    map_pages_to_xen((unsigned long)ret, page_to_mfn(pg),
+                     1UL << order, PAGE_HYPERVISOR);

As mentioned earlier on for Arm, xenheap will always be mapped. So unless you have plan to tackle the Arm side as well, we should make sure that the behavior is not changed for Arm.

It feels to me we want to introduce a new Kconfig that is selected by x86 to tell whether the direct map is mapped. I would then implement maybe in xen/mm.h two stub (one for when the config is selected, the other when it is not).

return page_to_virt(pg);
  }
@@ -2165,6 +2169,8 @@ void free_xenheap_pages(void *v, unsigned int order)
          return;
memguard_guard_range(v, 1 << (order + PAGE_SHIFT));
+    ASSERT((unsigned long)v >= DIRECTMAP_VIRT_START);

This define does not exist for Arm32 so it will break compilation.

+    map_pages_to_xen((unsigned long)v, INVALID_MFN, 1UL << order, _PAGE_NONE);
free_heap_pages(virt_to_page(v), order, false);
  }
@@ -2189,6 +2195,7 @@ void *alloc_xenheap_pages(unsigned int order, unsigned 
int memflags)
  {
      struct page_info *pg;
      unsigned int i;
+    void *ret;
ASSERT(!in_irq()); @@ -2204,7 +2211,11 @@ void *alloc_xenheap_pages(unsigned int order, unsigned int memflags)
      for ( i = 0; i < (1u << order); i++ )
          pg[i].count_info |= PGC_xen_heap;
- return page_to_virt(pg);
+    ret = page_to_virt(pg);
+    map_pages_to_xen((unsigned long)ret, page_to_mfn(pg),
+                     1UL << order, PAGE_HYPERVISOR);
+
+    return ret;
  }
void free_xenheap_pages(void *v, unsigned int order)
@@ -2222,6 +2233,9 @@ void free_xenheap_pages(void *v, unsigned int order)
      for ( i = 0; i < (1u << order); i++ )
          pg[i].count_info &= ~PGC_xen_heap;
+ ASSERT((unsigned long)v >= DIRECTMAP_VIRT_START);
+    map_pages_to_xen((unsigned long)v, INVALID_MFN, 1UL << order, _PAGE_NONE);
+
      free_heap_pages(pg, order, true);
  }

Cheers,

--
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.