Patchwork [v2,12/22] piix_pci: wrap memory update in a transaction

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Submitter Avi Kivity
Date Aug. 24, 2011, 1:40 p.m.
Message ID <1314193259-27092-13-git-send-email-avi@redhat.com>
Download mbox | patch
Permalink /patch/111372/
State New
Headers show

Comments

Avi Kivity - Aug. 24, 2011, 1:40 p.m.
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.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 hw/piix_pci.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

Patch

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 @@  static void i440fx_update_memory_mappings(PCII440FXState *d)
     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 @@  static void i440fx_update_memory_mappings(PCII440FXState *d)
             d->smram_enabled = false;
         }
     }
+    memory_region_transaction_commit();
 }
 
 static void i440fx_set_smm(int val, void *arg)