[PATCHv2 06/13] qemu: add flag to disable MSI-X by default

Michael S. Tsirkin
2009-06-02T15:06:10Z

Add global flag to disable MSI-X by default. This is useful primarily
to make images loadable by older qemu (without msix). Even when MSI-X
is disabled by flag, you can still load images that have MSI-X enabled.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/msix.c | 3 +++
qemu-options.hx | 2 ++
vl.c | 3 +++
3 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/hw/msix.c b/hw/msix.c
index 4db2fc1..970a8ca 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -122,6 +122,9 @@ void msix_write_config(PCIDevice *dev, uint32_t addr,
uint32_t val, int len)
{
unsigned enable_pos = dev->msix_cap + MSIX_ENABLE_OFFSET;
+ if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))
+ return;
+
if (addr + len <= enable_pos || addr > enable_pos)
return;

diff --git a/qemu-options.hx b/qemu-options.hx
index 87af798..fd041a4 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1575,3 +1575,5 @@ DEF("semihosting", 0, QEMU_OPTION_semihosting,
DEF("old-param", 0, QEMU_OPTION_old_param,
"-old-param old param mode\n")
#endif
+DEF("disable-msix", 0, QEMU_OPTION_disable_msix,
+ "-disable-msix disable msix support for PCI devices (enabled by default)\n")
diff --git a/vl.c b/vl.c
index 2c1f0e0..2757d4f 100644
--- a/vl.c
+++ b/vl.c
@@ -134,6 +134,7 @@ int main(int argc, char **argv)
#include "hw/usb.h"
#include "hw/pcmcia.h"
#include "hw/pc.h"
+#include "hw/msix.h"
#include "hw/audiodev.h"
#include "hw/isa.h"
#include "hw/baum.h"
@@ -5557,6 +5558,8 @@ int main(int argc, char **argv, char **envp)
xen_mode = XEN_ATTACH;
break;
#endif
+ case QEMU_OPTION_disable_msix:
+ msix_disable = 1;
}
}
}
--
1.6.3.1.56.g79e1.dirty