On Fri, Jan 13, 2012 at 6:11 PM, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote: > On Fri, Jan 13, 2012 at 7:45 AM, Liu ping fan <kernelfans@xxxxxxxxx> wrote: >> On Thu, Jan 12, 2012 at 5:21 PM, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote: >>> On Thu, Jan 12, 2012 at 4:38 AM, Liu ping fan <kernelfans@xxxxxxxxx> wrote: >>>> Could anybody give some description about the implement of hyercall in >>>> kvm? Or give some links about it? >>> >>> Try git grep hypercall arch/x86/kvm. >>> >>> Take a look at arch/x86/kvm/x86.c kvm_set_msr_common() and >>> kvm_emulate_hypercall(). Some of the KVM time-keeping, minimal HyperV >>> support, and async page faults live there. Also see >>> arch/x86/include/asm/kvm_para.h. >>> >>> Hypercalls are architecture-specific so if you are interested in ppc >>> or s390, check those arch directories. >>> >> Thanks, but when I tried to start from the macro "____PVOP_VCALL", but >> lost in it. If there is some document like the hypercall in Xen, this >> will be appreciated. (And I guest Hypercall in kvm is the same as Xen >> which is very similar to syscall, right?) > > You can read about paravirt_ops to understand why that layer of > indirection is present: > http://lwn.net/Articles/194543/ > > But that macro is not the actual hypercall instructions, just a > mechanism for runtime-patching the kernel depending on whether it's > running on bare metal, KVM, Xen, etc. > > What you really should look at if you're interested in specific > paravirt features that you are interested in. For example, > arch/x86/kernel/kvmclock.c implements a paravirt clock using > "paravirt" Model Specific Registers and a shared memory region as the > guest<->host interface. So I guess you could say KVM paravirt uses > several mechanisms for host<->guest interaction. > Ok, thank you very much. You give a great help ping fan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
