[Qemu-devel] [PATCH 20/26] pseries: Use correct dispatcher for PCI config space accesses

[Alexander Graf <agraf@suse.de>]

From: David Gibson <david@gibson.dropbear.id.au>

The pseries machine expects a para-virtualized guest and so supplies RTAS
functions (via a hypercall) for performing PCI config space access.
Currently the implementation of these calls into
pci_default_{read,write}_config().  However this would be incorrect for
any PCI device which overrides the default config read/write functions.
AFAICT there's only one such device today, but we should still get it
right.  In addition the pci_host_config_{read,write}_common() functions
which do correctly do this dispatch, perform bounds checking on the config
space address, lack of which currently leads to an exploitable bug.

This patch corrects the problem.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 hw/spapr_pci.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/spapr_pci.c b/hw/spapr_pci.c
index 2550e19..f3f9246 100644
--- a/hw/spapr_pci.c
+++ b/hw/spapr_pci.c
@@ -82,7 +82,7 @@ static void rtas_ibm_read_pci_config(sPAPREnvironment *spapr,
     }
     size = rtas_ld(args, 3);
     addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
-    val = pci_default_read_config(dev, addr, size);
+    val = pci_host_config_read_common(dev, addr, pci_config_size(dev), size);
     rtas_st(rets, 0, 0);
     rtas_st(rets, 1, val);
 }
@@ -101,7 +101,7 @@ static void rtas_read_pci_config(sPAPREnvironment *spapr,
     }
     size = rtas_ld(args, 1);
     addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
-    val = pci_default_read_config(dev, addr, size);
+    val = pci_host_config_read_common(dev, addr, pci_config_size(dev), size);
     rtas_st(rets, 0, 0);
     rtas_st(rets, 1, val);
 }
@@ -122,7 +122,7 @@ static void rtas_ibm_write_pci_config(sPAPREnvironment *spapr,
     val = rtas_ld(args, 4);
     size = rtas_ld(args, 3);
     addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
-    pci_default_write_config(dev, addr, val, size);
+    pci_host_config_write_common(dev, addr, pci_config_size(dev), val, size);
     rtas_st(rets, 0, 0);
 }
 
@@ -141,7 +141,7 @@ static void rtas_write_pci_config(sPAPREnvironment *spapr,
     val = rtas_ld(args, 2);
     size = rtas_ld(args, 1);
     addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
-    pci_default_write_config(dev, addr, val, size);
+    pci_host_config_write_common(dev, addr, pci_config_size(dev), val, size);
     rtas_st(rets, 0, 0);
 }
 
-- 
1.6.0.2