From: Ashish Kalra <ashish.kalra@amd.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Radim Krcmar <rkrcmar@redhat.com>, Joerg Roedel <joro@8bytes.org>,
Borislav Petkov <bp@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
David Rientjes <rientjes@google.com>, X86 ML <x86@kernel.org>,
kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 10/12] mm: x86: Invoke hypercall when page encryption status is changed
Date: Thu, 13 Feb 2020 22:28:25 +0000 [thread overview]
Message-ID: <20200213222825.GA8784@ashkalra_ubuntu_server> (raw)
In-Reply-To: <CALCETrX6Oo00NXn2QfR=eOKD9wvWiov_=WBRwb7V266=hJ2Duw@mail.gmail.com>
On Wed, Feb 12, 2020 at 09:42:02PM -0800, Andy Lutomirski wrote:
>> On Wed, Feb 12, 2020 at 5:18 PM Ashish Kalra <Ashish.Kalra@amd.com> wrote:
>> >
>> > From: Brijesh Singh <brijesh.singh@amd.com>
> >
> > Invoke a hypercall when a memory region is changed from encrypted ->
> > decrypted and vice versa. Hypervisor need to know the page encryption
> > status during the guest migration.
>>
>> What happens if the guest memory status doesn't match what the
>> hypervisor thinks it is? What happens if the guest gets migrated
>> between the hypercall and the associated flushes?
This is basically same as the dirty page tracking and logging being done
during Live Migration. As with dirty page tracking and logging we
maintain a page encryption bitmap in the kernel which keeps tracks of
guest's page encrypted/decrypted state changes and this bitmap is
sync'ed regularly from kernel to qemu and also during the live migration
process, therefore any dirty pages whose encryption status will change
during migration, should also have their page status updated when the
page encryption bitmap is sync'ed.
Also i think that when the amount of dirty pages reach a low threshold,
QEMU stops the source VM and then transfers all the remaining dirty
pages, so at that point, there will also be a final sync of the page
encryption bitmap, there won't be any hypercalls after this as the
source VM has been stopped and the remaining VM state gets transferred.
Thanks,
Ashish
next prev parent reply other threads:[~2020-02-13 22:28 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 1:14 [PATCH 00/12] SEV Live Migration Patchset Ashish Kalra
2020-02-13 1:14 ` [PATCH 01/12] KVM: SVM: Add KVM_SEV SEND_START command Ashish Kalra
2020-03-09 21:28 ` Steve Rutherford
2020-03-10 0:19 ` Steve Rutherford
2020-02-13 1:15 ` [PATCH 02/12] KVM: SVM: Add KVM_SEND_UPDATE_DATA command Ashish Kalra
2020-03-10 1:04 ` Steve Rutherford
2020-03-12 1:49 ` Ashish Kalra
2020-02-13 1:16 ` [PATCH 03/12] KVM: SVM: Add KVM_SEV_SEND_FINISH command Ashish Kalra
2020-03-10 1:09 ` Steve Rutherford
2020-02-13 1:16 ` [PATCH 04/12] KVM: SVM: Add support for KVM_SEV_RECEIVE_START command Ashish Kalra
2020-03-10 1:41 ` Steve Rutherford
2020-03-12 0:38 ` Ashish Kalra
2020-03-12 2:55 ` Steve Rutherford
2020-02-13 1:16 ` [PATCH 05/12] KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command Ashish Kalra
2020-02-13 1:16 ` [PATCH 06/12] KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command Ashish Kalra
2020-02-13 1:17 ` [PATCH 07/12] KVM: x86: Add AMD SEV specific Hypercall3 Ashish Kalra
2020-02-13 1:17 ` [PATCH 08/12] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall Ashish Kalra
2020-02-20 2:39 ` Steve Rutherford
2020-02-20 5:28 ` Ashish Kalra
2020-02-20 21:21 ` Ashish Kalra
2020-02-13 1:17 ` [PATCH 09/12] KVM: x86: Introduce KVM_GET_PAGE_ENC_BITMAP ioctl Ashish Kalra
2020-02-27 17:57 ` Venu Busireddy
2020-02-27 18:18 ` Venu Busireddy
2020-02-27 19:38 ` Ashish Kalra
2020-02-13 1:18 ` [PATCH 10/12] mm: x86: Invoke hypercall when page encryption status is changed Ashish Kalra
2020-02-13 5:42 ` Andy Lutomirski
2020-02-13 22:28 ` Ashish Kalra [this message]
2020-02-14 18:56 ` Andy Lutomirski
2020-02-14 20:36 ` Ashish Kalra
2020-02-20 1:58 ` Steve Rutherford
2020-02-20 2:12 ` Andy Lutomirski
2020-02-20 3:29 ` Steve Rutherford
2020-02-20 15:54 ` Brijesh Singh
2020-02-20 20:43 ` Steve Rutherford
2020-02-20 22:43 ` Brijesh Singh
2020-02-20 23:23 ` Steve Rutherford
2020-02-20 23:40 ` Andy Lutomirski
2020-02-13 1:18 ` [PATCH 11/12] KVM: x86: Introduce KVM_SET_PAGE_ENC_BITMAP ioctl Ashish Kalra
2020-02-13 1:18 ` [PATCH 12/12] KVM: x86: Introduce KVM_PAGE_ENC_BITMAP_RESET ioctl Ashish Kalra
2020-02-13 5:43 ` [PATCH 00/12] SEV Live Migration Patchset Andy Lutomirski
2020-02-13 23:09 ` Ashish Kalra
2020-02-14 18:58 ` Andy Lutomirski
2020-02-17 19:49 ` Ashish Kalra
2020-03-03 1:05 ` Steve Rutherford
2020-03-03 4:42 ` Ashish Kalra
2020-03-19 13:05 ` Paolo Bonzini
2020-03-19 16:18 ` Ashish Kalra
2020-03-19 16:24 ` Paolo Bonzini
2020-02-14 2:10 ` Brijesh Singh
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