[PATCHv5 06/13] qemu: add flag to disable MSI-X by default

Michael S. Tsirkin
2009-06-18T13:17:09Z

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 | 5 ++++-
qemu-options.hx | 2 ++
vl.c | 3 +++
3 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/hw/msix.c b/hw/msix.c
index a448eab..cc62a83 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;

@@ -242,7 +245,7 @@ int msix_init(struct PCIDevice *dev, unsigned short nentries,

dev->msix_table_page = qemu_mallocz(MSIX_PAGE_SIZE);

- dev->msix_mmio_index = cpu_register_io_memory(0, msix_mmio_read,
+ dev->msix_mmio_index = cpu_register_io_memory(msix_mmio_read,
msix_mmio_write, dev);
if (dev->msix_mmio_index == -1) {
ret = -EBUSY;
diff --git a/qemu-options.hx b/qemu-options.hx
index 9d5e05a..aa02615 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1584,3 +1584,5 @@ 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 3242c23..f7c67bb 100644
--- a/vl.c
+++ b/vl.c
@@ -135,6 +135,7 @@ 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"
@@ -5699,6 +5700,8 @@ int main(int argc, char **argv, char **envp)
xen_mode = XEN_ATTACH;
break;
#endif
+ case QEMU_OPTION_disable_msix:
+ msix_disable = 1;
}
}
}
--
1.6.2.2