[Xen-devel] [PATCH v6 1/4] xen: introduce a helper to allocate non-contiguous memory

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

The allocator uses independent calls to alloc_domheap_pages in order to get
the desired amount of memory and then maps all the independent physical
addresses into a contiguous virtual address space.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Tested-by: Julien Grall <julien.grall@xxxxxxxxxx> (ARM)
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Changes since v5:
 - Call vunmap before freeing the pages in vfree.
 - Simplify the fail case by reusing i.

Changes since v4:
 - Remove the red-black tree, the same can be achieved by doing a VA -> MFN
   translation.
 - Provide a vzalloc that zeroes the allocated memory area.
 - Allocate domheap annonymous pages.
---
 xen/common/vmap.c          | 60 ++++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/mm.h   |  2 ++
 xen/include/asm-x86/page.h |  2 ++
 xen/include/xen/vmap.h     |  3 +++
 4 files changed, 67 insertions(+)

diff --git a/xen/common/vmap.c b/xen/common/vmap.c
index 739d468..4111982 100644
--- a/xen/common/vmap.c
+++ b/xen/common/vmap.c
@@ -215,4 +215,64 @@ void vunmap(const void *va)
 #endif
     vm_free(va);
 }
+
+void *vmalloc(size_t size)
+{
+    unsigned long *mfn;
+    size_t pages, i;
+    struct page_info *pg;
+    void *va;
+
+    ASSERT( size != 0 );
+
+    pages = PFN_UP(size);
+    mfn = xmalloc_array(unsigned long, pages);
+    if ( mfn == NULL )
+        return NULL;
+
+    for ( i = 0; i < pages; i++ )
+    {
+        pg = alloc_domheap_page(NULL, 0);
+        if ( pg == NULL )
+            goto error;
+        mfn[i] = page_to_mfn(pg);
+    }
+
+    va = vmap(mfn, pages);
+    if ( va == NULL )
+        goto error;
+
+    xfree(mfn);
+    return va;
+
+ error:
+    while ( i-- )
+         free_domheap_page(mfn_to_page(mfn[i]));
+    xfree(mfn);
+    return NULL;
+}
+
+void *vzalloc(size_t size)
+{
+    void *p = vmalloc(size);
+
+    return p ? memset(p, 0, size) : p;
+}
+
+void vfree(void *va)
+{
+    unsigned int i, pages = vm_size(va);
+    struct page_info *pg;
+    PAGE_LIST_HEAD(pg_list);
+
+    ASSERT( pages != 0 );
+
+    for ( i = 0; i < pages; i++ )
+        page_list_add(vmap_to_page(va + i * PAGE_SIZE), &pg_list);
+
+    vunmap(va);
+
+    while ( (pg = page_list_remove_head(&pg_list)) != NULL )
+        free_domheap_page(pg);
+}
 #endif
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index d25e485..c0afcec 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -208,6 +208,8 @@ static inline void __iomem *ioremap_wc(paddr_t start, 
size_t len)
 #define pfn_to_paddr(pfn) ((paddr_t)(pfn) << PAGE_SHIFT)
 #define paddr_to_pfn(pa)  ((unsigned long)((pa) >> PAGE_SHIFT))
 #define paddr_to_pdx(pa)    pfn_to_pdx(paddr_to_pfn(pa))
+#define vmap_to_mfn(va)     paddr_to_pfn(virt_to_maddr((vaddr_t)va))
+#define vmap_to_page(va)    mfn_to_page(vmap_to_mfn(va))
 
 /* Page-align address and convert to frame number format */
 #define paddr_to_pfn_aligned(paddr)    paddr_to_pfn(PAGE_ALIGN(paddr))
diff --git a/xen/include/asm-x86/page.h b/xen/include/asm-x86/page.h
index a8bc999..8977a76 100644
--- a/xen/include/asm-x86/page.h
+++ b/xen/include/asm-x86/page.h
@@ -262,6 +262,8 @@ void copy_page_sse2(void *, const void *);
 #define pfn_to_paddr(pfn)   __pfn_to_paddr(pfn)
 #define paddr_to_pfn(pa)    __paddr_to_pfn(pa)
 #define paddr_to_pdx(pa)    pfn_to_pdx(paddr_to_pfn(pa))
+#define vmap_to_mfn(va)     l1e_get_pfn(*virt_to_xen_l1e((unsigned long)(va)))
+#define vmap_to_page(va)    mfn_to_page(vmap_to_mfn(va))
 
 #endif /* !defined(__ASSEMBLY__) */
 
diff --git a/xen/include/xen/vmap.h b/xen/include/xen/vmap.h
index b1923dd..a13591d 100644
--- a/xen/include/xen/vmap.h
+++ b/xen/include/xen/vmap.h
@@ -11,6 +11,9 @@ void *__vmap(const unsigned long *mfn, unsigned int 
granularity,
              unsigned int nr, unsigned int align, unsigned int flags);
 void *vmap(const unsigned long *mfn, unsigned int nr);
 void vunmap(const void *);
+void *vmalloc(size_t size);
+void *vzalloc(size_t size);
+void vfree(void *va);
 
 void __iomem *ioremap(paddr_t, size_t);
 
-- 
1.9.5 (Apple Git-50.3)


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