Xen devel - Sep 2005 - [PATCH]blkfront change to support unmodified linux

This patch is to make blkfront can work both in xen-linux and in
unmodified guest which is shadow_model_translate enabled.

Signed-off-by: Xiaofeng Ling <xiaofeng.ling@intel.com>
Signed-off-by: Arun Sharma <arun.sharma@intel.com>

diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
+++ b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
@@ -511,7 +511,7 @@
  	FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);

  	err = gnttab_grant_foreign_access(info->backend_id,
-					  virt_to_mfn(info->ring.sring), 0);
+					  virt_to_xfn(info->ring.sring), 0);
  	if (err == -ENOSPC) {
  		free_page((unsigned long)info->ring.sring);
  		info->ring.sring = 0;
diff -r 287d36b46fa3 linux-2.6-xen-sparse/include/asm-xen/asm-i386/io.h
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/io.h	
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/io.h	
@@ -101,7 +101,17 @@
   * Change "struct page" to physical address.
   */
  #define page_to_pseudophys(page) ((dma_addr_t)page_to_pfn(page) << 
PAGE_SHIFT)
+#ifndef CONFIG_XEN_SHADOW_TRANSLATE
  #define page_to_phys(page)	 (phys_to_machine(page_to_pseudophys(page)))
+#else
+#define page_to_phys(page)	 (page_to_pseudophys(page))
+#endif
+
+#ifndef CONFIG_XEN_SHADOW_TRANSLATE
+#define virt_to_xfn(va)	 (virt_to_mfn(va))
+#else
+#define virt_to_xfn(va)	 (virt_to_phys(va) >> PAGE_SHIFT)
+#endif

  #define bio_to_pseudophys(bio)	 (page_to_pseudophys(bio_page((bio))) + \
  				  (unsigned long) bio_offset((bio)))


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On 5 Sep 2005, at 06:41, Xiaofeng Ling wrote:
> This patch is to make blkfront can work both in xen-linux and in
> unmodified guest which is shadow_model_translate enabled.
phys == machine from the p.o.v. of a shadow-translated guest, so why 
not modify virt_to_mfn and friends appropriately?

  -- Keir


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Keir Fraser wrote:
> 
> On 5 Sep 2005, at 06:41, Xiaofeng Ling wrote:
> 
>> This patch is to make blkfront can work both in xen-linux and in
>> unmodified guest which is shadow_model_translate enabled.
> 
> 
> phys == machine from the p.o.v. of a shadow-translated guest, so why not 
> modify virt_to_mfn and friends appropriately?
Sorry, I don''t catch your meaning.
vmx guest is in shadow-translate mode, and gpfn need to translate to mfn 
in hypervisor. see the macro:

#define __gpfn_to_mfn(_d, gpfn)                        \
     ({                                                 \
         ASSERT(current->domain == (_d));               \
         (shadow_mode_translate(_d))                    \
         ? get_mfn_from_pfn(gpfn)                \
         : (gpfn);                                      \
     })

#define __gpfn_to_mfn_foreign(_d, gpfn)                \
     ( (shadow_mode_translate(_d))                      \
       ? gpfn_to_mfn_foreign(_d, gpfn)                  \
       : (gpfn) )

So I rename virt_to_mfn to virt_to_xfn which means if not in shadow 
translate mode, it will do translate in guest. for vmx guest, don''t
need
the translation in guest. What is your suggestion?

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