From: Sean Christopherson <seanjc@google.com>
To: Michael Roth <michael.roth@amd.com>
Cc: kvm@vger.kernel.org, linux-coco@lists.linux.dev,
linux-mm@kvack.org, linux-crypto@vger.kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de, mingo@redhat.com, jroedel@suse.de,
thomas.lendacky@amd.com, hpa@zytor.com, ardb@kernel.org,
pbonzini@redhat.com, vkuznets@redhat.com, jmattson@google.com,
luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com,
pgonda@google.com, peterz@infradead.org,
srinivas.pandruvada@linux.intel.com, rientjes@google.com,
dovmurik@linux.ibm.com, tobin@ibm.com, bp@alien8.de,
vbabka@suse.cz, kirill@shutemov.name, ak@linux.intel.com,
tony.luck@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com,
alpergun@google.com, jarkko@kernel.org, ashish.kalra@amd.com,
nikunj.dadhania@amd.com, pankaj.gupta@amd.com,
liam.merwick@oracle.com
Subject: Re: [PATCH v14 21/22] crypto: ccp: Add the SNP_{PAUSE,RESUME}_ATTESTATION commands
Date: Fri, 26 Apr 2024 12:57:08 -0700 [thread overview]
Message-ID: <ZiwHFMfExfXvqDIr@google.com> (raw)
In-Reply-To: <20240426173515.6pio42iqvjj2aeac@amd.com>
On Fri, Apr 26, 2024, Michael Roth wrote:
> On Wed, Apr 24, 2024 at 05:15:40PM -0700, Sean Christopherson wrote:
> > On Sun, Apr 21, 2024, Michael Roth wrote:
> > > These commands can be used to pause servicing of guest attestation
> > > requests. This useful when updating the reported TCB or signing key with
> > > commands such as SNP_SET_CONFIG/SNP_COMMIT/SNP_VLEK_LOAD, since they may
> > > in turn require updates to userspace-supplied certificates, and if an
> > > attestation request happens to be in-flight at the time those updates
> > > are occurring there is potential for a guest to receive a certificate
> > > blob that is out of sync with the effective signing key for the
> > > attestation report.
> > >
> > > These interfaces also provide some versatility with how similar
> > > firmware/certificate update activities can be handled in the future.
> >
> > Wait, IIUC, this is using the kernel to get two userspace components to not
> > stomp over each other. Why is this the kernel's problem to solve?
>
> It's not that they are stepping on each other, but that kernel and
> userspace need to coordinate on updating 2 components whose updates need
> to be atomic from a guest perspective. Take an update to VLEK key for
> instance:
>
> 1) management gets a new VLEK endorsement key from KDS along with
What is "management"? I assume its some userspace daemon?
> associated certificate chain
> 2) management uses SNP_VLEK_LOAD to update key
> 3) management updates the certs at the path VMM will grab them
> from when the EXT_GUEST_REQUEST userspace exit is issued
>
> If an attestation request comes in after 2), but before 3), then the
> guest sees an attestation report signed with the new key, but still
> gets the old certificate.
>
> If you reverse the ordering:
>
> 1) management gets a new VLEK endorsement key from KDS along with
> associated certificate chain
> 2) management updates the certs at the path VMM will grab them
> from when the EXT_GUEST_REQUEST userspace exit is issued
> 3) management uses SNP_VLEK_LOAD to update key
>
> then an attestation request between 2) and 3) will result in the guest
> getting the new cert, but getting an attestation report signed with an old
> endorsement key.
>
> Providing a way to pause guest attestation requests prior to 2), and
> resume after 3), provides a straightforward way to make those updates
> atomic to the guest.
Assuming "management" is a userspace component, I still don't see why this
requires kernel involvement. "management" can tell VMMs to pause attestation
without having to bounce through the kernel. It doesn't even require a push
model, e.g. wrap/redirect the certs with a file that has a "pause" flag and a
sequence counter.
next prev parent reply other threads:[~2024-04-26 19:57 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-21 18:01 [PATCH v14 00/22] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-04-21 18:01 ` [PATCH v14 01/22] KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=y Michael Roth
2024-04-21 18:01 ` [PATCH v14 02/22] KVM: SEV: Add support to handle AP reset MSR protocol Michael Roth
2024-04-21 18:01 ` [PATCH v14 03/22] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests Michael Roth
2024-04-24 20:21 ` Sean Christopherson
2024-04-25 20:52 ` Michael Roth
2024-04-25 21:55 ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 04/22] KVM: SEV: Add initial SEV-SNP support Michael Roth
2024-04-21 18:01 ` [PATCH v14 05/22] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2024-04-24 23:26 ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 06/22] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2024-04-24 23:58 ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 07/22] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2024-04-21 18:01 ` [PATCH v14 08/22] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-04-21 18:01 ` [PATCH v14 09/22] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-04-24 20:59 ` Sean Christopherson
2024-04-25 22:00 ` Michael Roth
2024-04-25 22:13 ` Sean Christopherson
2024-04-26 17:16 ` Michael Roth
2024-04-26 20:14 ` Sean Christopherson
2024-04-26 22:24 ` Michael Roth
2024-04-26 22:48 ` Michael Roth
2024-04-21 18:01 ` [PATCH v14 10/22] KVM: SEV: Add support to handle " Michael Roth
2024-04-21 18:01 ` [PATCH v14 11/22] KVM: SEV: Add support to handle RMP nested page faults Michael Roth
2024-04-21 18:01 ` [PATCH v14 12/22] KVM: SEV: Support SEV-SNP AP Creation NAE event Michael Roth
2024-04-21 18:01 ` [PATCH v14 13/22] KVM: SEV: Add support for GHCB-based termination requests Michael Roth
2024-04-21 18:01 ` [PATCH v14 14/22] KVM: SEV: Implement gmem hook for initializing private pages Michael Roth
2024-04-21 18:01 ` [PATCH v14 15/22] KVM: SEV: Implement gmem hook for invalidating " Michael Roth
2024-04-21 18:01 ` [PATCH v14 16/22] KVM: x86: Implement gmem hook for determining max NPT mapping level Michael Roth
2024-04-25 0:45 ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 17/22] KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP Michael Roth
2024-04-25 0:17 ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 18/22] KVM: SVM: Add module parameter to enable SEV-SNP Michael Roth
2024-04-21 18:01 ` [PATCH v14 19/22] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-04-21 18:01 ` [PATCH v14 20/22] crypto: ccp: Add the SNP_VLEK_LOAD command Michael Roth
2024-04-21 18:01 ` [PATCH v14 21/22] crypto: ccp: Add the SNP_{PAUSE,RESUME}_ATTESTATION commands Michael Roth
2024-04-25 0:15 ` Sean Christopherson
2024-04-26 17:35 ` Michael Roth
2024-04-26 19:57 ` Sean Christopherson [this message]
2024-04-26 21:46 ` Michael Roth
2024-04-27 0:10 ` Sean Christopherson
2024-04-27 1:32 ` Michael Roth
2024-04-29 14:27 ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 22/22] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event Michael Roth
2024-04-25 0:10 ` Sean Christopherson
2024-04-26 17:57 ` Michael Roth
2024-04-23 16:21 ` [PATCH v14 23/22] [SQUASH] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-04-23 16:21 ` [PATCH v14 24/22] [SQUASH] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-04-23 16:21 ` [PATCH v14 25/22] [SQUASH] KVM: SEV: Add support to handle " Michael Roth
2024-04-23 16:21 ` [PATCH v14 26/22] [SQUASH] KVM: SEV: Add support for GHCB-based termination requests Michael Roth
2024-04-23 16:21 ` [PATCH v14 27/22] [SQUASH] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-04-23 16:21 ` [PATCH v14 28/22] [SQUASH] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST " Michael Roth
2024-04-23 21:36 ` Jarkko Sakkinen
2024-04-23 16:21 ` [PATCH v14 29/22] [SQUASH] KVM: SEV: Support SEV-SNP AP Creation " Michael Roth
2024-04-23 16:31 ` [PATCH v14 00/22] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-04-24 16:51 ` Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZiwHFMfExfXvqDIr@google.com \
--to=seanjc@google.com \
--cc=ak@linux.intel.com \
--cc=alpergun@google.com \
--cc=ardb@kernel.org \
--cc=ashish.kalra@amd.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=dovmurik@linux.ibm.com \
--cc=hpa@zytor.com \
--cc=jarkko@kernel.org \
--cc=jmattson@google.com \
--cc=jroedel@suse.de \
--cc=kirill@shutemov.name \
--cc=kvm@vger.kernel.org \
--cc=liam.merwick@oracle.com \
--cc=linux-coco@lists.linux.dev \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=michael.roth@amd.com \
--cc=mingo@redhat.com \
--cc=nikunj.dadhania@amd.com \
--cc=pankaj.gupta@amd.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=pgonda@google.com \
--cc=rientjes@google.com \
--cc=sathyanarayanan.kuppuswamy@linux.intel.com \
--cc=slp@redhat.com \
--cc=srinivas.pandruvada@linux.intel.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=tobin@ibm.com \
--cc=tony.luck@intel.com \
--cc=vbabka@suse.cz \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.