# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Date 1187077969 -32400
# Node ID b53a87fec6dc7a9f2cc3b3b7df72fa8b2c7fe081
# Parent cf7a9141e7f884a14cfab8d3785c95dea85749be
[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
xencomm_desc::address array.
PATCHNAME: xencomm_multiple_page
Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
diff -r cf7a9141e7f8 -r b53a87fec6dc xen/common/xencomm.c
--- a/xen/common/xencomm.c Tue Aug 14 17:17:01 2007 +0900
+++ b/xen/common/xencomm.c Tue Aug 14 16:52:49 2007 +0900
@@ -17,6 +17,7 @@
 *
 * Authors: Hollis Blanchard <hollisb@xxxxxxxxxx>
 * Tristan Gingold <tristan.gingold@xxxxxxxx>
+ * Isaku Yamahata <yamahata@xxxxxxxxxxxxx> multiple page support
 */
 
 #include <xen/config.h>
@@ -81,10 +82,11 @@ 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
@@ -94,21 +96,9 @@ 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
@@ -136,15 +126,38 @@ 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;
 }
@@ -236,11 +249,14 @@ xencomm_copy_from_guest(void *to, const 
 
 /* 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;
 unsigned int chunksz;
 unsigned int chunk_skip;
 
+ if (xencomm_ctxt_next(&ctxt, i))
+ goto out;
+ src_paddr = *xencomm_ctxt_address(&ctxt);
 if (src_paddr == XENCOMM_INVALID) {
 i++;
 continue;
@@ -353,11 +369,14 @@ xencomm_copy_to_guest(void *to, const vo
 
 /* 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;
 unsigned int chunksz;
 unsigned int chunk_skip;
 
+ if (xencomm_ctxt_next(&ctxt, i))
+ goto out;
+ dest_paddr = *xencomm_ctxt_address(&ctxt);
 if (dest_paddr == XENCOMM_INVALID) {
 i++;
 continue;
@@ -401,21 +420,28 @@ 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 long *address;
+ unsigned long dest_paddr;
 unsigned int pgoffset;
 unsigned int chunksz;
 unsigned int 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++;
 continue;
@@ -435,8 +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)
@@ -452,7 +480,9 @@ int xencomm_handle_is_null(void *handle)
 return 1;
 
 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;
 }

Attachment: 15728_b53a87fec6dc_xencomm_multiple_page.patch
Description: Text Data

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