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# HG changeset patch
# User kfraser@localhost.localdomain
# Date 1188311547 -3600
# Node ID c93e2a822d6f0232ff6f57787eb1c432641cffa1
# Parent b1c3b9df7d9a7edf0f70f8869fa05b30e77ddbe0
[xen, xencomm] xencomm multiple page support
Current implementation doesn't allow struct xencomm_desc::address
array to be more than single page. On IA64 it causes 64GB+ domain
creation failure. This patch generalizes xencomm to allow multipage

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
---
xen/common/xencomm.c | 97 +++++++++++++++++++++++++++++++++------------------
1 files changed, 63 insertions(+), 34 deletions(-)

diff -r b1c3b9df7d9a -r c93e2a822d6f xen/common/xencomm.c
--- a/xen/common/xencomm.c Tue Aug 28 15:31:56 2007 +0100
+++ b/xen/common/xencomm.c Tue Aug 28 15:32:27 2007 +0100
@@ -17,6 +17,7 @@
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
* Tristan Gingold <tristan.gingold@bull.net>
+ * Isaku Yamahata <yamahata@valinux.co.jp> multiple page support
*/

#include <xen/config.h>
@@ -82,10 +83,11 @@ xencomm_desc_cross_page_boundary(unsigne
}

struct xencomm_ctxt {
- struct xencomm_desc *desc;
-
+ struct xencomm_desc __user *desc_in_paddr;
uint32_t nr_addrs;
+
struct page_info *page;
+ unsigned long *address;
};

static uint32_t
@@ -95,21 +97,9 @@ xencomm_ctxt_nr_addrs(const struct xenco
}

static unsigned long*
-xencomm_ctxt_address(struct xencomm_ctxt *ctxt, int i)
-{
- return &ctxt->desc->address[i];
-}
-
-/* check if struct xencomm_desc and address array cross page boundary */
-static int
-xencomm_ctxt_cross_page_boundary(struct xencomm_ctxt *ctxt)
-{
- unsigned long saddr = (unsigned long)ctxt->desc;
- unsigned long eaddr =
- (unsigned long)&ctxt->desc->address[ctxt->nr_addrs] - 1;
- if ( (saddr >> PAGE_SHIFT) != (eaddr >> PAGE_SHIFT) )
- return 1;
- return 0;
+xencomm_ctxt_address(struct xencomm_ctxt *ctxt)
+{
+ return ctxt->address;
}

static int
@@ -138,16 +128,40 @@ xencomm_ctxt_init(const void* handle, st
return -EINVAL;
}

- ctxt->desc = desc;
ctxt->nr_addrs = desc->nr_addrs; /* copy before use.
* It is possible for a guest domain to
* modify concurrently.
*/
+ ctxt->desc_in_paddr = (struct xencomm_desc*)handle;
ctxt->page = page;
- if ( xencomm_ctxt_cross_page_boundary(ctxt) )
- {
- put_page(page);
- return -EINVAL;
+ ctxt->address = &desc->address[0];
+ return 0;
+}
+
+static int
+xencomm_ctxt_next(struct xencomm_ctxt *ctxt, int i)
+{
+ BUG_ON(i >= ctxt->nr_addrs);
+ /* in i == 0 case, we already calculated in xecomm_addr_init() */
+ if ( i != 0 )
+ ctxt->address++;
+
+ /* When crossing page boundary, machine address must be calculated. */
+ if ( ((unsigned long)ctxt->address & ~PAGE_MASK) == 0 )
+ {
+ unsigned long paddr =
+ (unsigned long)&(ctxt->desc_in_paddr->address[i]);
+ struct page_info *page;
+ int ret;
+
+ ret = xencomm_get_page(paddr, &page);
+ if ( ret == 0 )
+ {
+ put_page(ctxt->page);
+ ctxt->page = page;
+ ctxt->address = xencomm_vaddr(paddr, page);
+ }
+ return ret;
}
return 0;
}
@@ -238,9 +252,12 @@ xencomm_copy_from_guest(
/* Iterate through the descriptor, copying up to a page at a time */
while ( (to_pos < n) && (i < xencomm_ctxt_nr_addrs(&ctxt)) )
{
- unsigned long src_paddr = *xencomm_ctxt_address(&ctxt, i);
+ unsigned long src_paddr;
unsigned int pgoffset, chunksz, chunk_skip;

+ if ( xencomm_ctxt_next(&ctxt, i) )
+ goto out;
+ src_paddr = *xencomm_ctxt_address(&ctxt);
if ( src_paddr == XENCOMM_INVALID )
{
i++;
@@ -354,9 +371,12 @@ xencomm_copy_to_guest(
/* Iterate through the descriptor, copying up to a page at a time */
while ( (from_pos < n) && (i < xencomm_ctxt_nr_addrs(&ctxt)) )
{
- unsigned long dest_paddr = *xencomm_ctxt_address(&ctxt, i);
+ unsigned long dest_paddr;
unsigned int pgoffset, chunksz, chunk_skip;

+ if ( xencomm_ctxt_next(&ctxt, i) )
+ goto out;
+ dest_paddr = *xencomm_ctxt_address(&ctxt);
if ( dest_paddr == XENCOMM_INVALID )
{
i++;
@@ -402,22 +422,27 @@ int xencomm_add_offset(void **handle, un
{
struct xencomm_ctxt ctxt;
int i = 0;
+ int res = 0;

if ( xencomm_is_inline(*handle) )
return xencomm_inline_add_offset(handle, bytes);

- if ( xencomm_ctxt_init(handle, &ctxt) )
- return -1;
+ res = xencomm_ctxt_init(handle, &ctxt);
+ if ( res != 0 )
+ return res;

/* Iterate through the descriptor incrementing addresses */
while ( (bytes > 0) && (i < xencomm_ctxt_nr_addrs(&ctxt)) )
{
- unsigned long *address = xencomm_ctxt_address(&ctxt, i);
- unsigned long dest_paddr = *address;
- unsigned int pgoffset;
- unsigned int chunksz;
- unsigned int chunk_skip;
-
+ unsigned long *address;
+ unsigned long dest_paddr;
+ unsigned int pgoffset, chunksz, chunk_skip;
+
+ res = xencomm_ctxt_next(&ctxt, i);
+ if ( res )
+ goto out;
+ address = xencomm_ctxt_address(&ctxt);
+ dest_paddr = *address;
if ( dest_paddr == XENCOMM_INVALID )
{
i++;
@@ -436,8 +461,10 @@ int xencomm_add_offset(void **handle, un

i++;
}
+
+out:
xencomm_ctxt_done(&ctxt);
- return 0;
+ return res;
}

int xencomm_handle_is_null(void *handle)
@@ -454,7 +481,9 @@ int xencomm_handle_is_null(void *handle)

for ( i = 0; i < xencomm_ctxt_nr_addrs(&ctxt); i++ )
{
- if ( *xencomm_ctxt_address(&ctxt, i) != XENCOMM_INVALID )
+ if ( xencomm_ctxt_next(&ctxt, i) )
+ goto out;
+ if ( *xencomm_ctxt_address(&ctxt) != XENCOMM_INVALID )
{
res = 0;
goto out;

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