WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH 03/11] xen: fix qemu_map_cache with size != MCACHE_BU

To: "qemu-devel@xxxxxxxxxx Developers" <qemu-devel@xxxxxxxxxx>
Subject: [Xen-devel] [PATCH 03/11] xen: fix qemu_map_cache with size != MCACHE_BUCKET_SIZE
From: Alexander Graf <agraf@xxxxxxx>
Date: Sun, 19 Jun 2011 05:39:42 +0200
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx Devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Anthony Liguori <anthony@xxxxxxxxxxxxx>, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Delivery-date: Mon, 20 Jun 2011 02:35:03 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1308452228-11055-1-git-send-email-agraf@xxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <1308452228-11055-1-git-send-email-agraf@xxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

Fix the implementation of qemu_map_cache: correctly support size
arguments different from 0 or MCACHE_BUCKET_SIZE.
The new implementation supports locked mapcache entries with size
multiple of MCACHE_BUCKET_SIZE. qemu_invalidate_entry can correctly
find and unmap these "large" mapcache entries given that the virtual
address passed to qemu_invalidate_entry is the same returned by
qemu_map_cache when the locked mapcache entry was created.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Signed-off-by: Alexander Graf <agraf@xxxxxxx>
---
 xen-mapcache.c |   77 +++++++++++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 65 insertions(+), 12 deletions(-)

diff --git a/xen-mapcache.c b/xen-mapcache.c
index 349cc62..90fbd49 100644
--- a/xen-mapcache.c
+++ b/xen-mapcache.c
@@ -43,14 +43,16 @@
 typedef struct MapCacheEntry {
     target_phys_addr_t paddr_index;
     uint8_t *vaddr_base;
-    DECLARE_BITMAP(valid_mapping, MCACHE_BUCKET_SIZE >> XC_PAGE_SHIFT);
+    unsigned long *valid_mapping;
     uint8_t lock;
+    target_phys_addr_t size;
     struct MapCacheEntry *next;
 } MapCacheEntry;
 
 typedef struct MapCacheRev {
     uint8_t *vaddr_req;
     target_phys_addr_t paddr_index;
+    target_phys_addr_t size;
     QTAILQ_ENTRY(MapCacheRev) next;
 } MapCacheRev;
 
@@ -68,6 +70,15 @@ typedef struct MapCache {
 
 static MapCache *mapcache;
 
+static inline int test_bits(int nr, int size, const unsigned long *addr)
+{
+    unsigned long res = find_next_zero_bit(addr, size + nr, nr);
+    if (res >= nr + size)
+        return 1;
+    else
+        return 0;
+}
+
 void qemu_map_cache_init(void)
 {
     unsigned long size;
@@ -115,11 +126,15 @@ static void qemu_remap_bucket(MapCacheEntry *entry,
     err = qemu_mallocz(nb_pfn * sizeof (int));
 
     if (entry->vaddr_base != NULL) {
-        if (munmap(entry->vaddr_base, size) != 0) {
+        if (munmap(entry->vaddr_base, entry->size) != 0) {
             perror("unmap fails");
             exit(-1);
         }
     }
+    if (entry->valid_mapping != NULL) {
+        qemu_free(entry->valid_mapping);
+        entry->valid_mapping = NULL;
+    }
 
     for (i = 0; i < nb_pfn; i++) {
         pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i;
@@ -134,6 +149,9 @@ static void qemu_remap_bucket(MapCacheEntry *entry,
 
     entry->vaddr_base = vaddr_base;
     entry->paddr_index = address_index;
+    entry->size = size;
+    entry->valid_mapping = (unsigned long *) qemu_mallocz(sizeof(unsigned 
long) *
+            BITS_TO_LONGS(size >> XC_PAGE_SHIFT));
 
     bitmap_zero(entry->valid_mapping, nb_pfn);
     for (i = 0; i < nb_pfn; i++) {
@@ -151,32 +169,47 @@ uint8_t *qemu_map_cache(target_phys_addr_t phys_addr, 
target_phys_addr_t size, u
     MapCacheEntry *entry, *pentry = NULL;
     target_phys_addr_t address_index  = phys_addr >> MCACHE_BUCKET_SHIFT;
     target_phys_addr_t address_offset = phys_addr & (MCACHE_BUCKET_SIZE - 1);
+    target_phys_addr_t __size = size;
 
     trace_qemu_map_cache(phys_addr);
 
-    if (address_index == mapcache->last_address_index && !lock) {
+    if (address_index == mapcache->last_address_index && !lock && !__size) {
         trace_qemu_map_cache_return(mapcache->last_address_vaddr + 
address_offset);
         return mapcache->last_address_vaddr + address_offset;
     }
 
+    /* size is always a multiple of MCACHE_BUCKET_SIZE */
+    if ((address_offset + (__size % MCACHE_BUCKET_SIZE)) > MCACHE_BUCKET_SIZE)
+        __size += MCACHE_BUCKET_SIZE;
+    if (__size % MCACHE_BUCKET_SIZE)
+        __size += MCACHE_BUCKET_SIZE - (__size % MCACHE_BUCKET_SIZE);
+    if (!__size)
+        __size = MCACHE_BUCKET_SIZE;
+
     entry = &mapcache->entry[address_index % mapcache->nr_buckets];
 
-    while (entry && entry->lock && entry->paddr_index != address_index && 
entry->vaddr_base) {
+    while (entry && entry->lock && entry->vaddr_base &&
+            (entry->paddr_index != address_index || entry->size != __size ||
+             !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
+                 entry->valid_mapping))) {
         pentry = entry;
         entry = entry->next;
     }
     if (!entry) {
         entry = qemu_mallocz(sizeof (MapCacheEntry));
         pentry->next = entry;
-        qemu_remap_bucket(entry, size ? : MCACHE_BUCKET_SIZE, address_index);
+        qemu_remap_bucket(entry, __size, address_index);
     } else if (!entry->lock) {
         if (!entry->vaddr_base || entry->paddr_index != address_index ||
-            !test_bit(address_offset >> XC_PAGE_SHIFT, entry->valid_mapping)) {
-            qemu_remap_bucket(entry, size ? : MCACHE_BUCKET_SIZE, 
address_index);
+                entry->size != __size ||
+                !test_bits(address_offset >> XC_PAGE_SHIFT, size >> 
XC_PAGE_SHIFT,
+                    entry->valid_mapping)) {
+            qemu_remap_bucket(entry, __size, address_index);
         }
     }
 
-    if (!test_bit(address_offset >> XC_PAGE_SHIFT, entry->valid_mapping)) {
+    if(!test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
+                entry->valid_mapping)) {
         mapcache->last_address_index = -1;
         trace_qemu_map_cache_return(NULL);
         return NULL;
@@ -189,6 +222,7 @@ uint8_t *qemu_map_cache(target_phys_addr_t phys_addr, 
target_phys_addr_t size, u
         entry->lock++;
         reventry->vaddr_req = mapcache->last_address_vaddr + address_offset;
         reventry->paddr_index = mapcache->last_address_index;
+        reventry->size = entry->size;
         QTAILQ_INSERT_HEAD(&mapcache->locked_entries, reventry, next);
     }
 
@@ -231,13 +265,16 @@ void qemu_map_cache_unlock(void *buffer)
 
 ram_addr_t qemu_ram_addr_from_mapcache(void *ptr)
 {
+    MapCacheEntry *entry = NULL, *pentry = NULL;
     MapCacheRev *reventry;
     target_phys_addr_t paddr_index;
+    target_phys_addr_t size;
     int found = 0;
 
     QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
         if (reventry->vaddr_req == ptr) {
             paddr_index = reventry->paddr_index;
+            size = reventry->size;
             found = 1;
             break;
         }
@@ -252,7 +289,17 @@ ram_addr_t qemu_ram_addr_from_mapcache(void *ptr)
         return 0;
     }
 
-    return paddr_index << MCACHE_BUCKET_SHIFT;
+    entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
+    while (entry && (entry->paddr_index != paddr_index || entry->size != 
size)) {
+        pentry = entry;
+        entry = entry->next;
+    }
+    if (!entry) {
+        DPRINTF("Trying to find address %p that is not in the mapcache!\n", 
ptr);
+        return 0;
+    }
+    return (reventry->paddr_index << MCACHE_BUCKET_SHIFT) +
+        ((unsigned long) ptr - (unsigned long) entry->vaddr_base);
 }
 
 void qemu_invalidate_entry(uint8_t *buffer)
@@ -260,6 +307,7 @@ void qemu_invalidate_entry(uint8_t *buffer)
     MapCacheEntry *entry = NULL, *pentry = NULL;
     MapCacheRev *reventry;
     target_phys_addr_t paddr_index;
+    target_phys_addr_t size;
     int found = 0;
 
     if (mapcache->last_address_vaddr == buffer) {
@@ -269,6 +317,7 @@ void qemu_invalidate_entry(uint8_t *buffer)
     QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
         if (reventry->vaddr_req == buffer) {
             paddr_index = reventry->paddr_index;
+            size = reventry->size;
             found = 1;
             break;
         }
@@ -284,7 +333,7 @@ void qemu_invalidate_entry(uint8_t *buffer)
     qemu_free(reventry);
 
     entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
-    while (entry && entry->paddr_index != paddr_index) {
+    while (entry && (entry->paddr_index != paddr_index || entry->size != 
size)) {
         pentry = entry;
         entry = entry->next;
     }
@@ -298,10 +347,11 @@ void qemu_invalidate_entry(uint8_t *buffer)
     }
 
     pentry->next = entry->next;
-    if (munmap(entry->vaddr_base, MCACHE_BUCKET_SIZE) != 0) {
+    if (munmap(entry->vaddr_base, entry->size) != 0) {
         perror("unmap fails");
         exit(-1);
     }
+    qemu_free(entry->valid_mapping);
     qemu_free(entry);
 }
 
@@ -328,13 +378,16 @@ void qemu_invalidate_map_cache(void)
             continue;
         }
 
-        if (munmap(entry->vaddr_base, MCACHE_BUCKET_SIZE) != 0) {
+        if (munmap(entry->vaddr_base, entry->size) != 0) {
             perror("unmap fails");
             exit(-1);
         }
 
         entry->paddr_index = 0;
         entry->vaddr_base = NULL;
+        entry->size = 0;
+        qemu_free(entry->valid_mapping);
+        entry->valid_mapping = NULL;
     }
 
     mapcache->last_address_index = -1;
-- 
1.6.0.2


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>