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xen: Avoid VLA

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Avoid using a variable length array.

We allocate the `dirty_bitmap' buffer only once when we start tracking
for dirty bits.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190618112341.513-5-anthony.perard@citrix.com>
This commit is contained in:
Anthony PERARD 2019-06-18 12:23:41 +01:00
parent 345f42b4be
commit 34fbbc164f
1 changed files with 11 additions and 4 deletions
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15
hw/i386/xen/xen-hvm.c
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@ -120,6 +120,8 @@ typedef struct XenIOState {
DeviceListener device_listener; DeviceListener device_listener;
hwaddr free_phys_offset; hwaddr free_phys_offset;
const XenPhysmap *log_for_dirtybit; const XenPhysmap *log_for_dirtybit;
/* Buffer used by xen_sync_dirty_bitmap */
unsigned long *dirty_bitmap;
Notifier exit; Notifier exit;
Notifier suspend; Notifier suspend;
@ -465,6 +467,8 @@ static int xen_remove_from_physmap(XenIOState *state,
QLIST_REMOVE(physmap, list); QLIST_REMOVE(physmap, list);
if (state->log_for_dirtybit == physmap) { if (state->log_for_dirtybit == physmap) {
state->log_for_dirtybit = NULL; state->log_for_dirtybit = NULL;
g_free(state->dirty_bitmap);
state->dirty_bitmap = NULL;
} }
g_free(physmap); g_free(physmap);
@ -615,7 +619,7 @@ static void xen_sync_dirty_bitmap(XenIOState *state,
{ {
hwaddr npages = size >> TARGET_PAGE_BITS; hwaddr npages = size >> TARGET_PAGE_BITS;
const int width = sizeof(unsigned long) * 8; const int width = sizeof(unsigned long) * 8;
unsigned long bitmap[DIV_ROUND_UP(npages, width)]; size_t bitmap_size = DIV_ROUND_UP(npages, width);
int rc, i, j; int rc, i, j;
const XenPhysmap *physmap = NULL; const XenPhysmap *physmap = NULL;
@ -627,13 +631,14 @@ static void xen_sync_dirty_bitmap(XenIOState *state,
if (state->log_for_dirtybit == NULL) { if (state->log_for_dirtybit == NULL) {
state->log_for_dirtybit = physmap; state->log_for_dirtybit = physmap;
state->dirty_bitmap = g_new(unsigned long, bitmap_size);
} else if (state->log_for_dirtybit != physmap) { } else if (state->log_for_dirtybit != physmap) {
/* Only one range for dirty bitmap can be tracked. */ /* Only one range for dirty bitmap can be tracked. */
return; return;
} }
rc = xen_track_dirty_vram(xen_domid, start_addr >> TARGET_PAGE_BITS, rc = xen_track_dirty_vram(xen_domid, start_addr >> TARGET_PAGE_BITS,
npages, bitmap); npages, state->dirty_bitmap);
if (rc < 0) { if (rc < 0) {
#ifndef ENODATA #ifndef ENODATA
#define ENODATA ENOENT #define ENODATA ENOENT
@ -647,8 +652,8 @@ static void xen_sync_dirty_bitmap(XenIOState *state,
return; return;
} }
for (i = 0; i < ARRAY_SIZE(bitmap); i++) { for (i = 0; i < bitmap_size; i++) {
unsigned long map = bitmap[i]; unsigned long map = state->dirty_bitmap[i];
while (map != 0) { while (map != 0) {
j = ctzl(map); j = ctzl(map);
map &= ~(1ul << j); map &= ~(1ul << j);
@ -678,6 +683,8 @@ static void xen_log_stop(MemoryListener *listener, MemoryRegionSection *section,
if (old & ~new & (1 << DIRTY_MEMORY_VGA)) { if (old & ~new & (1 << DIRTY_MEMORY_VGA)) {
state->log_for_dirtybit = NULL; state->log_for_dirtybit = NULL;
g_free(state->dirty_bitmap);
state->dirty_bitmap = NULL;
/* Disable dirty bit tracking */ /* Disable dirty bit tracking */
xen_track_dirty_vram(xen_domid, 0, 0, NULL); xen_track_dirty_vram(xen_domid, 0, 0, NULL);
} }