[Qemu-devel] Fw:Re:Re: How to access guest memory from qemu device internal

[Kaiyuan]

+ Cc qemu-devel
> -----Origin email-----
> From: Greg Kurz <address@hidden>
> Sent Time: Friday, November 21, 2014
> To: Kaiyuan <address@hidden>
> Cc: qemu-devel <address@hidden>
> Subject: Re: [Qemu-devel] How to access guest memory from qemu device internal
> 
> On Thu, 20 Nov 2014 21:25:18 +0800 (GMT+08:00)
> Kaiyuan <address@hidden> wrote:
> > Hello, all
> >  
> > I added a custom device to qemu. This device is attached to sysbus by mmio 
> > and has an address register in which device should access the guest memory 
> > the register point to.
> > I write a bare-metal program that pass an address like 0x1234ABCD to this 
> > address register. Inside qemu device code I added, if device reads value 
> > from register and directly accesses this value of 0x1234ABCD, it will 
> > access host memory 0x1234ABCD rather than guest  memory 0x1234ABCD.
> > Does qemu provide some functions that allow device to access guest memory 
> > address?
> > 
> 
> Have a look at *_phys* functions in the <exec/cpu-common.h> QEMU header file 
> (cpu_physical_memory_read() for
> exemple).
> 
Thanks, Greg. It's useful to me. cpu_physical_memory_read() looks like a 
wrapper of translating guest addr to host addrIs there a function that 
translates guest address to host physical address?