Re: [Qemu-devel] [RFC PATCH 7/7] target-arm: Hacky implementation of kvm_arch_reset_vcpu() for KVM ARM64

[Pranavkumar Sawargaonkar]

Hi Christoffer,

On 14 March 2014 09:21, Christoffer Dall <address@hidden> wrote:
> On Thu, Feb 27, 2014 at 04:05:04PM +0530, Pranavkumar Sawargaonkar wrote:
>> Hi Peter,
>>
>> On 27 February 2014 15:23, Peter Maydell <address@hidden> wrote:
>> > On 27 February 2014 06:51, Pranavkumar Sawargaonkar
>> > <address@hidden> wrote:
>> >> We need to "Feed the kernel back its initial register state" using KVM
>> >> ioctls for KVM ARM64 (just like KVM ARM). This means we need to save
>> >> the "initial register state" in kvm_arch_init_vcpu() which is not the
>> >> case for KVM ARM64 right now. In simpler work, we are depended upon
>> >> VCPU register init/save/restore for implementing kvm_arch_reset_vcpu().
>> >>
>> >> This patch adds a hacky implementation of kvm_arch_reset_vcpu() which
>> >> only works for "mach-virt". As-per this hacky implemenation, we re-init
>> >> the VCPU using kvm_arch_init_vcpu() so that all registers of VCPU are
>> >> set to their reset values by in-kernel KVM code.
>> >
>> > Re-initing the VCPU is actually the right way to do this -- it is feeding
>> > all the register state back to KVM that is the hack. (One day I may
>> > fix 32 bit ARM to re-init the VCPU).
>> >
>>
> Didn't I promise a patch to the KVM Documentation some time to clarify
> this?  Hmmm.

Sorry I was not aware about it about you are going to send a patch to
KVM documentation to clarify this.
Also PMM mentioned that this is not the hack and actually the correct way.
Hence I will revise the patch with removal of Hack word.

>
> -Christoffer

Thanks,
Pranav