[AMD Public Use] -----Original Message----- From: Sean Christopherson <sea...@google.com> Sent: Tuesday, February 16, 2021 7:03 PM To: Kalra, Ashish <ashish.ka...@amd.com> Cc: pbonz...@redhat.com; t...@linutronix.de; mi...@redhat.com; h...@zytor.com; rkrc...@redhat.com; j...@8bytes.org; b...@suse.de; Lendacky, Thomas <thomas.lenda...@amd.com>; x...@kernel.org; k...@vger.kernel.org; linux-kernel@vger.kernel.org; srutherf...@google.com; venu.busire...@oracle.com; Singh, Brijesh <brijesh.si...@amd.com> Subject: Re: [PATCH v10 10/16] KVM: x86: Introduce KVM_GET_SHARED_PAGES_LIST ioctl
On Thu, Feb 04, 2021, Ashish Kalra wrote: > From: Brijesh Singh <brijesh.si...@amd.com> > > The ioctl is used to retrieve a guest's shared pages list. >What's the performance hit to boot time if KVM_HC_PAGE_ENC_STATUS is passed >through to userspace? That way, userspace could manage the set of pages >in >whatever data structure they want, and these get/set ioctls go away. What is the advantage of passing KVM_HC_PAGE_ENC_STATUS through to user-space ? As such it is just a simple interface to get the shared page list via the get/set ioctl's. simply an array is passed to these ioctl to get/set the shared pages list. >Also, aren't there plans for an in-guest migration helper? If so, do we have >any idea what that interface will look like? E.g. if we're going to end up >with a full >fledged driver in the guest, why not bite the bullet now and >bypass KVM entirely? Even the in-guest migration helper will be using page encryption status hypercalls, so some interface is surely required. Also the in-guest migration will be mainly an OVMF component, won't really be a full fledged kernel driver in the guest. Thanks, Ashish
