> - We introduce another new vm level ioctl focus on the encrypted
>     guest memory accessing:
>
>     KVM_MEMORY_ENCRYPT_{READ,WRITE}_MEMORY
>
>     struct kvm_rw_memory rw;
>     rw.addr = gpa_OR_hva;
>     rw.buf = (__u64)src;
>     rw.len = len;
>     kvm_vm_ioctl(kvm_state,
>                  KVM_MEMORY_ENCRYPT_{READ,WRITE}_MEMORY,
>                  &rw);
>
>     This new ioctl has more neutral and general name for its
>     purpose, the debugging support of AMD SEV and INTEL TDX
>     can be covered by a unify QEMU implementation on x86 with this
>     ioctl. Although only INTEL TD guest is supported in this series,
>     AMD SEV could be also supported with implementation of this
>     ioctl in KVM, plus small modifications in QEMU to enable the
>     unify part.

A general comment, we have sev_ioctl() interface for SEV guests and
probably this new vm level ioctl will not work for us.

It probably makes more sense to do this TDX/SEV level abstraction 
using the Memory Region's ram_debug_ops, which can point these to 
TDX specific vm level ioctl and SEV specific ioctl at the lowest
level of this interface.

Thanks,
Ashish

>-----Original Message-----
>From: Ashish Kalra <Ashish.Kalra@amd.com>
>Sent: Thursday, September 02, 2021 22:05
>To: yuan.yao@linux.intel.com
>Cc: Thomas.Lendacky@amd.com; armbru@redhat.com; ashish.kalra@amd.com; brijesh.singh@amd.com;
>dgilbert@redhat.com; ehabkost@redhat.com; Yamahata, Isaku <isaku.yamahata@intel.com>; kvm@vger.kernel.org;
>mst@redhat.com; mtosatti@redhat.com; pbonzini@redhat.com; qemu-devel@nongnu.org; Yao, Yuan
><yuan.yao@intel.com>
>Subject: [RFC][PATCH v1 00/10] Enable encrypted guest memory access in QEMU
>
>> - We introduce another new vm level ioctl focus on the encrypted
>>     guest memory accessing:
>>
>>     KVM_MEMORY_ENCRYPT_{READ,WRITE}_MEMORY
>>
>>     struct kvm_rw_memory rw;
>>     rw.addr = gpa_OR_hva;
>>     rw.buf = (__u64)src;
>>     rw.len = len;
>>     kvm_vm_ioctl(kvm_state,
>>                  KVM_MEMORY_ENCRYPT_{READ,WRITE}_MEMORY,
>>                  &rw);
>>
>>     This new ioctl has more neutral and general name for its
>>     purpose, the debugging support of AMD SEV and INTEL TDX
>>     can be covered by a unify QEMU implementation on x86 with this
>>     ioctl. Although only INTEL TD guest is supported in this series,
>>     AMD SEV could be also supported with implementation of this
>>     ioctl in KVM, plus small modifications in QEMU to enable the
>>     unify part.
>
>A general comment, we have sev_ioctl() interface for SEV guests and
>probably this new vm level ioctl will not work for us.
>
>It probably makes more sense to do this TDX/SEV level abstraction
>using the Memory Region's ram_debug_ops, which can point these to
>TDX specific vm level ioctl and SEV specific ioctl at the lowest
>level of this interface.
>
Hi Ashish,

Yes, this new ioctl is now working as the low-level interface for 
Memory Region's ram_debug_ops. SEV can use 
kvm_setup_set_memory_region_debug_ops() to install a new
callback to KVM for installing SEV only low-level implementation,
then call kvm_set_memory_region_debug_ops() to do Memory
Region's ram_debug_ops installation later.


>Thanks,
>Ashish

Hello Yuan,

On Thu, Sep 02, 2021 at 11:23:50PM +0000, Yao, Yuan wrote:
> >-----Original Message-----
> >From: Ashish Kalra <Ashish.Kalra@amd.com>
> >Sent: Thursday, September 02, 2021 22:05
> >To: yuan.yao@linux.intel.com
> >Cc: Thomas.Lendacky@amd.com; armbru@redhat.com; ashish.kalra@amd.com; brijesh.singh@amd.com;
> >dgilbert@redhat.com; ehabkost@redhat.com; Yamahata, Isaku <isaku.yamahata@intel.com>; kvm@vger.kernel.org;
> >mst@redhat.com; mtosatti@redhat.com; pbonzini@redhat.com; qemu-devel@nongnu.org; Yao, Yuan
> ><yuan.yao@intel.com>
> >Subject: [RFC][PATCH v1 00/10] Enable encrypted guest memory access in QEMU
> >
> >> - We introduce another new vm level ioctl focus on the encrypted
> >>     guest memory accessing:
> >>
> >>     KVM_MEMORY_ENCRYPT_{READ,WRITE}_MEMORY
> >>
> >>     struct kvm_rw_memory rw;
> >>     rw.addr = gpa_OR_hva;
> >>     rw.buf = (__u64)src;
> >>     rw.len = len;
> >>     kvm_vm_ioctl(kvm_state,
> >>                  KVM_MEMORY_ENCRYPT_{READ,WRITE}_MEMORY,
> >>                  &rw);
> >>
> >>     This new ioctl has more neutral and general name for its
> >>     purpose, the debugging support of AMD SEV and INTEL TDX
> >>     can be covered by a unify QEMU implementation on x86 with this
> >>     ioctl. Although only INTEL TD guest is supported in this series,
> >>     AMD SEV could be also supported with implementation of this
> >>     ioctl in KVM, plus small modifications in QEMU to enable the
> >>     unify part.
> >
> >A general comment, we have sev_ioctl() interface for SEV guests and
> >probably this new vm level ioctl will not work for us.
> >
> >It probably makes more sense to do this TDX/SEV level abstraction
> >using the Memory Region's ram_debug_ops, which can point these to
> >TDX specific vm level ioctl and SEV specific ioctl at the lowest
> >level of this interface.
> >
> Hi Ashish,
> 
> Yes, this new ioctl is now working as the low-level interface for 
> Memory Region's ram_debug_ops. SEV can use 
> kvm_setup_set_memory_region_debug_ops() to install a new
> callback to KVM for installing SEV only low-level implementation,
> then call kvm_set_memory_region_debug_ops() to do Memory
> Region's ram_debug_ops installation later.
> 
> 

Ok. Yes i think that should work. 

Thanks,
Ashish