gwj / at91sam9263 · Commits

  • pci: add default pci subsystem id for all devices (Gerd Hoffman) ...
    d350d97d 
    This sets a default PCI subsystem ID for all emulated PCI devices.  PCI
specs require this, so do it.

In many cases it is enougth to know the PCI ID to handle a device
correctly.  Sometimes a device driver must identify the exact piece of
hardware (via PCI Subsystem ID) though.

What does this patch to qemu devices:

Right now the emulated PCI devices have no PCI subsystem ID, only the
PCI ID.  The discussed patch sets a default PCI subsystem ID for all
emulated devices.  Which will make the qemu devices look pretty much
like in the laptop case: all PCI subsystem IDs will point to qemu by
default.

If a driver emulates a very specific piece of hardware where it has to
emulate more than just the PCI chip, it can overwrite the PCI subsystem
ID without problems.  The es1370 driver does that for example.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5986 c046a42c-6fe2-441c-8c8c-71466251a162
    aliguori authored
     
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  • KVM: Coalesced MMIO support ...
    f65ed4c1 
    MMIO exits are more expensive in KVM or Xen than in QEMU because they 
involve, at least, privilege transitions.  However, MMIO write 
operations can be effectively batched if those writes do not have side 
effects.

Good examples of this include VGA pixel operations when in a planar 
mode.  As it turns out, we can get a nice boost in other areas too.  
Laurent mentioned a 9.7% performance boost in iperf with the coalesced 
MMIO changes for the e1000 when he originally posted this work for KVM.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5961 c046a42c-6fe2-441c-8c8c-71466251a162
    aliguori authored
     
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