piix_pci: wrap memory update in a transaction
The code will remap all PAMs, even if just one is updated, resulting
in reduced performance. Wrap in a transaction to detect that those
other PAMs have not changed.
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index f892994..8f6ea42 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -142,6 +142,7 @@
int i, r;
uint32_t smram;
+ memory_region_transaction_begin();
update_pam(d, 0xf0000, 0x100000, (d->dev.config[I440FX_PAM] >> 4) & 3,
&d->pam_regions[0]);
for(i = 0; i < 12; i++) {
@@ -162,6 +163,7 @@
d->smram_enabled = false;
}
}
+ memory_region_transaction_commit();
}
static void i440fx_set_smm(int val, void *arg)
