minios: permit blkfront to write from mapped memory

diff -r 2c95a75433e4 extras/mini-os/blkfront.c
@@ -88,7 +88,7 @@ struct blkfront_dev *init_blkfront(char 
     SHARED_RING_INIT(s);
     FRONT_RING_INIT(&dev->ring, s, PAGE_SIZE);
 
-    dev->ring_ref = gnttab_grant_access(0,virt_to_mfn(s),0);
+    dev->ring_ref = gnttab_grant_access(0,virtual_to_mfn(s),0);
 
     evtchn_alloc_unbound_t op;
     op.dom = DOMID_SELF;

diff -r 2c95a75433e4 extras/mini-os/include/ia64/arch_mm.h
@@ -25,6 +25,7 @@
 #define __ARCH_MM_H__
 
 #include "page.h"
+#include "ia64_cpu.h"
 
 #define PFN_PHYS(x)	(pfn_to_page(x))
 #define PHYS_PFN(x)	(page_to_pfn(x))

@@ -32,6 +33,7 @@
 #define to_phys(x)	__pa(x)
 
 #define virt_to_mfn(x)	virt_to_pfn(x)
+#define virtual_to_mfn(x)      (ia64_tpa((uint64_t)(x)) >> PAGE_SHIFT)
 
 #define STACK_SIZE_PAGE_ORDER   1
 #define STACK_SIZE              (PAGE_SIZE * (1 << STACK_SIZE_PAGE_ORDER))

diff -r 2c95a75433e4 extras/mini-os/include/x86/arch_mm.h
@@ -226,6 +226,35 @@ static __inline__ paddr_t machine_to_phy
 #define pte_to_mfn(_pte)           (((_pte) & (PADDR_MASK&PAGE_MASK)) >> L1_PAGETABLE_SHIFT)
 #define pte_to_virt(_pte)          to_virt(mfn_to_pfn(pte_to_mfn(_pte)) << PAGE_SHIFT)
 
+
+#define PT_BASE			   ((pgentry_t *)start_info.pt_base)
+
+#ifdef __x86_64__
+#define virtual_to_l3(_virt)	   ((pgentry_t *)pte_to_virt(PT_BASE[l4_table_offset(_virt)]))
+#else
+#define virtual_to_l3(_virt)	   PT_BASE
+#endif
+
+#if defined(__x86_64__) || defined(CONFIG_X86_PAE)
+#define virtual_to_l2(_virt)	   ({ \
+	unsigned long __virt2 = (_virt); \
+	(pgentry_t *) pte_to_virt(virtual_to_l3(__virt2)[l3_table_offset(__virt2)]); \
+})
+#else
+#define virtual_to_l2(_virt)	   PT_BASE
+#endif
+
+#define virtual_to_l1(_virt)	   ({ \
+	unsigned long __virt1 = (_virt); \
+	(pgentry_t *) pte_to_virt(virtual_to_l2(__virt1)[l2_table_offset(__virt1)]); \
+})
+
+#define virtual_to_pte(_virt)	   ({ \
+	unsigned long __virt0 = (unsigned long) (_virt); \
+	virtual_to_l1(__virt0)[l1_table_offset(__virt0)]; \
+})
+#define virtual_to_mfn(_virt)	   pte_to_mfn(virtual_to_pte(_virt))
+
 #define map_frames(f, n) map_frames_ex(f, n, 1, 0, 1, DOMID_SELF, 0, L1_PROT)
 #define map_zero(n, a) map_frames_ex(&mfn_zero, n, 0, 0, a, DOMID_SELF, 0, L1_PROT_RO)

diff -r 9e92672385a5 extras/mini-os/blkfront.c
@@ -275,7 +275,7 @@ void blkfront_aio(struct blkfront_aiocb 
     for (j = 0; j < n; j++) {
 	uintptr_t data = start + j * PAGE_SIZE;
 	aiocbp->gref[j] = req->seg[j].gref =
-            gnttab_grant_access(0, virt_to_mfn(data), write);
+            gnttab_grant_access(0, virtual_to_mfn(data), write);
 	req->seg[j].first_sect = 0;
 	req->seg[j].last_sect = PAGE_SIZE / dev->sector_size - 1;
     }