# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Node ID bbea54da02b552ace34e502c5d8f803ea585741c
# Parent 4db818a7dc3f3bb3b9dace0a7fa8a1f80f2b0d26
[MINIOS] Mapping page frames on demand added to the memory management.
Signed-off-by: Steven Smith <sos22@xxxxxxxxx>
Signed-off-by: Grzegorz Milos <gm281@xxxxxxxxx>
---
extras/mini-os/gnttab.c | 158 ++++++++++++++++++++++++++++++++++++++++
extras/mini-os/include/gnttab.h | 14 +++
extras/mini-os/include/os.h | 57 ++++++++++++++
extras/mini-os/kernel.c | 6 +
4 files changed, 233 insertions(+), 2 deletions(-)
diff -r 4db818a7dc3f -r bbea54da02b5 extras/mini-os/include/os.h
--- a/extras/mini-os/include/os.h Wed Jul 05 14:29:13 2006 +0100
+++ b/extras/mini-os/include/os.h Wed Jul 05 14:29:57 2006 +0100
@@ -445,7 +445,62 @@ static __inline__ unsigned long __ffs(un
/********************* common i386 and x86_64 ****************************/
-
+struct __synch_xchg_dummy { unsigned long a[100]; };
+#define __synch_xg(x) ((struct __synch_xchg_dummy *)(x))
+
+#define synch_cmpxchg(ptr, old, new) \
+((__typeof__(*(ptr)))__synch_cmpxchg((ptr),\
+ (unsigned long)(old), \
+ (unsigned long)(new), \
+ sizeof(*(ptr))))
+
+static inline unsigned long __synch_cmpxchg(volatile void *ptr,
+ unsigned long old,
+ unsigned long new, int size)
+{
+ unsigned long prev;
+ switch (size) {
+ case 1:
+ __asm__ __volatile__("lock; cmpxchgb %b1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+ case 2:
+ __asm__ __volatile__("lock; cmpxchgw %w1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+#ifdef __x86_64__
+ case 4:
+ __asm__ __volatile__("lock; cmpxchgl %k1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+ case 8:
+ __asm__ __volatile__("lock; cmpxchgq %1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+#else
+ case 4:
+ __asm__ __volatile__("lock; cmpxchgl %1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+#endif
+ }
+ return old;
+}
static __inline__ void synch_set_bit(int nr, volatile void * addr)
diff -r 4db818a7dc3f -r bbea54da02b5 extras/mini-os/kernel.c
--- a/extras/mini-os/kernel.c Wed Jul 05 14:29:13 2006 +0100
+++ b/extras/mini-os/kernel.c Wed Jul 05 14:29:57 2006 +0100
@@ -35,6 +35,7 @@
#include <lib.h>
#include <sched.h>
#include <xenbus.h>
+#include <gnttab.h>
#include <xen/features.h>
#include <xen/version.h>
@@ -177,7 +178,10 @@ void start_kernel(start_info_t *si)
/* Init the console driver. */
init_console();
-
+
+ /* Init grant tables */
+ init_gnttab();
+
/* Init scheduler. */
init_sched();
diff -r 4db818a7dc3f -r bbea54da02b5 extras/mini-os/gnttab.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/extras/mini-os/gnttab.c Wed Jul 05 14:29:57 2006 +0100
@@ -0,0 +1,158 @@
+/*
+ ****************************************************************************
+ * (C) 2006 - Cambridge University
+ ****************************************************************************
+ *
+ * File: gnttab.c
+ * Author: Steven Smith (sos22@xxxxxxxxx)
+ * Changes: Grzegorz Milos (gm281@xxxxxxxxx)
+ *
+ * Date: July 2006
+ *
+ * Environment: Xen Minimal OS
+ * Description: Simple grant tables implementation. About as stupid as it's
+ * possible to be and still work.
+ *
+ ****************************************************************************
+ */
+#include <os.h>
+#include <mm.h>
+#include <gnttab.h>
+
+#define NR_RESERVED_ENTRIES 8
+
+#define NR_GRANT_FRAMES 4
+#define NR_GRANT_ENTRIES (NR_GRANT_FRAMES * PAGE_SIZE / sizeof(grant_entry_t))
+#define GNTTAB_LIST_END (NR_GRANT_ENTRIES + 1)
+
+static grant_entry_t *gnttab_table;
+static grant_ref_t gnttab_list[NR_GRANT_ENTRIES];
+static grant_ref_t gnttab_free_head;
+
+static grant_ref_t
+get_free_entries(int count)
+{
+ grant_ref_t ref;
+ grant_ref_t head;
+
+ ref = head = gnttab_free_head;
+ while (count-- > 1)
+ head = gnttab_list[head];
+ gnttab_free_head = gnttab_list[head];
+ gnttab_list[head] = GNTTAB_LIST_END;
+ return ref;
+}
+
+static void
+put_free_entry(grant_ref_t gref)
+{
+ gnttab_list[gref] = gnttab_free_head;
+ gnttab_free_head = gref;
+}
+
+grant_ref_t
+gnttab_grant_access(domid_t domid, unsigned long frame, int readonly)
+{
+ grant_ref_t ref;
+
+ ref = get_free_entries(1);
+ gnttab_table[ref].frame = frame;
+ gnttab_table[ref].domid = domid;
+ wmb();
+ readonly *= GTF_readonly;
+ gnttab_table[ref].flags = GTF_permit_access | readonly;
+
+ return ref;
+}
+
+grant_ref_t
+gnttab_grant_transfer(domid_t domid, unsigned long pfn)
+{
+ grant_ref_t ref;
+
+ ref = get_free_entries(1);
+ gnttab_table[ref].frame = pfn;
+ gnttab_table[ref].domid = domid;
+ wmb();
+ gnttab_table[ref].flags = GTF_accept_transfer;
+
+ return ref;
+}
+
+int
+gnttab_end_access(grant_ref_t ref)
+{
+ u16 flags, nflags;
+
+ nflags = gnttab_table[ref].flags;
+ do {
+ if ((flags = nflags) & (GTF_reading|GTF_writing)) {
+ printk("WARNING: g.e. still in use!\n");
+ return 0;
+ }
+ } while ((nflags = synch_cmpxchg(&gnttab_table[ref].flags, flags, 0)) !=
+ flags);
+
+ put_free_entry(ref);
+ return 1;
+}
+
+unsigned long
+gnttab_end_transfer(grant_ref_t ref)
+{
+ unsigned long frame;
+ u16 flags;
+
+ while (!((flags = gnttab_table[ref].flags) & GTF_transfer_committed)) {
+ if (synch_cmpxchg(&gnttab_table[ref].flags, flags, 0) == flags) {
+ printk("Release unused transfer grant.\n");
+ put_free_entry(ref);
+ return 0;
+ }
+ }
+
+ /* If a transfer is in progress then wait until it is completed. */
+ while (!(flags & GTF_transfer_completed)) {
+ flags = gnttab_table[ref].flags;
+ }
+
+ /* Read the frame number /after/ reading completion status. */
+ rmb();
+ frame = gnttab_table[ref].frame;
+
+ put_free_entry(ref);
+
+ return frame;
+}
+
+grant_ref_t
+gnttab_alloc_and_grant(void **map)
+{
+ unsigned long mfn;
+ grant_ref_t gref;
+
+ *map = (void *)alloc_page();
+ mfn = virt_to_mfn(*map);
+ gref = gnttab_grant_access(0, mfn, 0);
+ return gref;
+}
+
+void
+init_gnttab(void)
+{
+ struct gnttab_setup_table setup;
+ unsigned long frames[NR_GRANT_FRAMES];
+ int i;
+
+ for (i = NR_RESERVED_ENTRIES; i < NR_GRANT_ENTRIES; i++)
+ gnttab_list[i] = i + 1;
+ gnttab_free_head = NR_RESERVED_ENTRIES;
+
+ setup.dom = DOMID_SELF;
+ setup.nr_frames = NR_GRANT_FRAMES;
+ set_xen_guest_handle(setup.frame_list, frames);
+
+ HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
+ gnttab_table = map_frames(frames, NR_GRANT_FRAMES);
+ printk("gnttab_table mapped at %p.\n", gnttab_table);
+}
diff -r 4db818a7dc3f -r bbea54da02b5 extras/mini-os/include/gnttab.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/extras/mini-os/include/gnttab.h Wed Jul 05 14:29:57 2006 +0100
@@ -0,0 +1,14 @@
+#ifndef __GNTTAB_H__
+#define __GNTTAB_H__
+
+#include <xen/grant_table.h>
+
+void init_gnttab(void);
+grant_ref_t gnttab_alloc_and_grant(void **map);
+grant_ref_t gnttab_grant_access(domid_t domid, unsigned long frame,
+ int readonly);
+grant_ref_t gnttab_grant_transfer(domid_t domid, unsigned long pfn);
+unsigned long gnttab_end_transfer(grant_ref_t gref);
+int gnttab_end_access(grant_ref_t ref);
+
+#endif /* !__GNTTAB_H__ */
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