Re: :could anyone give me some instruction for KVM pci driver? Thanks

[Neo Jia <cyclonusj@gmail.com>]

On Wed, Aug 17, 2011 at 04:48:52PM +0800, liu pf wrote:
> Hi guys,
> 
> After objdump the driver, I found that the access to the pci-memmap
> register was optimized by GCC, and no code was generated.
> And the EPT in 2.6.39 is fine.

Are you registering a callback function for the register range you are going to
monitor on QEMU? You will see a VM_EXIT, which then trigger a mmio access from
KVM.

Thanks,
CJ

> 
> Thanks,
> Pierce
> 
> 
> On Fri, Aug 12, 2011 at 4:33 PM, liu pf <kernelfans@gmail.com> wrote:
> > Hi guys,
> >
> > When I develop a PCI device driver for qemu-kvm, I am suffering from
> > some problem, Could anyone give me some instruction? Thanks :)
> >
> > My solution consists of two parts:  emulated PCI device in Qemu and
> > corresponding PCI device driver in guest OS.
> > The emulated  device has a PCI -memmap registers. So as expected, when
> > the guest device driver wrote this area, we will capture such event in
> > Qemu.
> > But it failed to do so. After tracing the host kernel, I found that
> >  1. my guest PCI device driver had claimed the gpa from
> > pci_dev->resource[0].start=0xf0050000 to resource[0].end=0xf00500ff
> > and succeed to ioremap
> >  2. In host kernel,  I added "printk" after
> > handle_ept_violation(struct kvm_vcpu *vcpu) {gpa
> > =vmcs_read64(GUEST_PHYSICAL_ADDRESS); printk(..);}
> >    BUT, when guest wrote this "ioremap" area, the host did NOT hit
> > the region [0xf0050000,0xf00500ff]
> >
> >
> > I had thought that when accessing the emulated device, the gva ->gpa
> > has been set up by guest, so EPT violation will be the only reason
> > which caused guest exit .  And the event will be finally passed to the
> > user mode--qemu.  Am I right?
> >
> > And the most important is what I can do for the next step?
> >
> > BTW, I am sure that "kvm_enable_tdp". and kernel is 2.6.39, for config
> > file, pls see attachment.
> >
> >
> > Thanks,
> > Pierce
> >
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