From: Tom Lendacky <thomas.lendacky@amd.com>
To: Michael Roth <michael.roth@amd.com>, kvm@vger.kernel.org
Cc: 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, hpa@zytor.com,
ardb@kernel.org, pbonzini@redhat.com, seanjc@google.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 v12 29/29] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event
Date: Thu, 11 Apr 2024 08:33:47 -0500 [thread overview]
Message-ID: <5f0e74f2-6261-d836-5161-a525ed9c497a@amd.com> (raw)
In-Reply-To: <20240329225835.400662-30-michael.roth@amd.com>
On 3/29/24 17:58, Michael Roth wrote:
> Version 2 of GHCB specification added support for the SNP Extended Guest
> Request Message NAE event. This event serves a nearly identical purpose
> to the previously-added SNP_GUEST_REQUEST event, but allows for
> additional certificate data to be supplied via an additional
> guest-supplied buffer to be used mainly for verifying the signature of
> an attestation report as returned by firmware.
>
> This certificate data is supplied by userspace, so unlike with
> SNP_GUEST_REQUEST events, SNP_EXTENDED_GUEST_REQUEST events are first
> forwarded to userspace via a KVM_EXIT_VMGEXIT exit type, and then the
> firmware request is made only afterward.
>
> Implement handling for these events.
>
> Since there is a potential for race conditions where the
> userspace-supplied certificate data may be out-of-sync relative to the
> reported TCB or VLEK that firmware will use when signing attestation
> reports, make use of the synchronization mechanisms wired up to the
> SNP_{PAUSE,RESUME}_ATTESTATION SEV device ioctls such that the guest
> will be told to retry the request while attestation has been paused due
> to an update being underway on the system.
>
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> ---
> Documentation/virt/kvm/api.rst | 26 ++++++++++++
> arch/x86/include/asm/sev.h | 4 ++
> arch/x86/kvm/svm/sev.c | 75 ++++++++++++++++++++++++++++++++++
> arch/x86/kvm/svm/svm.h | 3 ++
> arch/x86/virt/svm/sev.c | 21 ++++++++++
> include/uapi/linux/kvm.h | 6 +++
> 6 files changed, 135 insertions(+)
>
> +static int snp_complete_ext_guest_req(struct kvm_vcpu *vcpu)
> +{
> + struct vcpu_svm *svm = to_svm(vcpu);
> + struct vmcb_control_area *control;
> + struct kvm *kvm = vcpu->kvm;
> + sev_ret_code fw_err = 0;
> + int vmm_ret;
> +
> + vmm_ret = vcpu->run->vmgexit.ext_guest_req.ret;
> + if (vmm_ret) {
> + if (vmm_ret == SNP_GUEST_VMM_ERR_INVALID_LEN)
> + vcpu->arch.regs[VCPU_REGS_RBX] =
> + vcpu->run->vmgexit.ext_guest_req.data_npages;
> + goto abort_request;
> + }
> +
> + control = &svm->vmcb->control;
> +
> + if (!__snp_handle_guest_req(kvm, control->exit_info_1, control->exit_info_2,
> + &fw_err))
> + vmm_ret = SNP_GUEST_VMM_ERR_GENERIC;
> +
> + /*
> + * Give errors related to stale transactions precedence to provide more
> + * potential options for servicing firmware while guests are running.
> + */
> + if (snp_transaction_is_stale(svm->snp_transaction_id))
> + vmm_ret = SNP_GUEST_VMM_ERR_BUSY;
I think having this after the call to the SEV firmware will cause an
issue. If the firmware has performed the attestation request
successfully in the __snp_handle_guest_req() call, then it will have
incremented the sequence number. If you return busy, then the sev-guest
driver will attempt to re-issue the request with the original sequence
number which will now fail. That failure will then be propagated back to
the sev-guest driver which will then disable the VMPCK key.
So I think you need to put this before the call to firmware.
Thanks,
Tom
> +
next prev parent reply other threads:[~2024-04-11 13:34 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-29 22:58 [PATCH v12 00/29] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 01/29] [TEMP] x86/kvm/Kconfig: Have KVM_AMD_SEV select ARCH_HAS_CC_PLATFORM Michael Roth
2024-03-29 22:58 ` [PATCH v12 02/29] [TEMP] x86/cc: Add cc_platform_set/_clear() helpers Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 03/29] [TEMP] x86/CPU/AMD: Track SNP host status with cc_platform_*() Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 04/29] [TEMP] fixup! KVM: SEV: sync FPU and AVX state at LAUNCH_UPDATE_VMSA time Michael Roth
2024-03-29 22:58 ` [PATCH v12 05/29] KVM: x86: Define RMP page fault error bits for #NPF Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 19:28 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 06/29] KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=y Michael Roth
2024-03-29 22:58 ` [PATCH v12 07/29] KVM: SEV: Add support to handle AP reset MSR protocol Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 08/29] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 09/29] KVM: SEV: Add initial SEV-SNP support Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 19:58 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 10/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:20 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 11/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:31 ` Paolo Bonzini
2024-04-01 22:22 ` Michael Roth
2024-04-02 22:58 ` Isaku Yamahata
2024-04-03 12:51 ` Paolo Bonzini
2024-04-03 15:37 ` Isaku Yamahata
2024-04-04 16:03 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 12/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:41 ` Paolo Bonzini
2024-04-01 23:17 ` Michael Roth
2024-04-03 12:56 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 13/29] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 14/29] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-03-29 22:58 ` [PATCH v12 15/29] KVM: SEV: Add support to handle " Michael Roth
2024-03-29 22:58 ` [PATCH v12 16/29] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Michael Roth
2024-03-30 20:51 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 17/29] KVM: SEV: Add support to handle RMP nested page faults Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:55 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 18/29] KVM: SEV: Use a VMSA physical address variable for populating VMCB Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 21:01 ` Paolo Bonzini
2024-04-16 11:53 ` Paolo Bonzini
2024-04-16 14:25 ` Tom Lendacky
2024-04-16 17:00 ` Paolo Bonzini
2024-04-17 20:57 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 19/29] KVM: SEV: Support SEV-SNP AP Creation NAE event Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 20/29] KVM: SEV: Add support for GHCB-based termination requests Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 21/29] KVM: SEV: Implement gmem hook for initializing private pages Michael Roth
2024-03-30 21:05 ` Paolo Bonzini
2024-03-30 21:05 ` Paolo Bonzini
2024-03-30 21:05 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 22/29] KVM: SEV: Implement gmem hook for invalidating " Michael Roth
2024-03-30 21:31 ` Paolo Bonzini
2024-03-30 21:31 ` Paolo Bonzini
2024-03-30 21:31 ` Paolo Bonzini
2024-04-18 19:57 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 23/29] KVM: x86: Implement gmem hook for determining max NPT mapping level Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 24/29] KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP Michael Roth
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 25/29] KVM: SVM: Add module parameter to enable the SEV-SNP Michael Roth
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 26/29] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-10 22:14 ` Tom Lendacky
2024-03-29 22:58 ` [PATCH v12 27/29] crypto: ccp: Add the SNP_VLEK_LOAD command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-10 22:20 ` Tom Lendacky
2024-03-29 22:58 ` [PATCH v12 28/29] crypto: ccp: Add the SNP_{PAUSE,RESUME}_ATTESTATION commands Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-10 22:27 ` Tom Lendacky
2024-03-29 22:58 ` [PATCH v12 29/29] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-11 13:33 ` Tom Lendacky [this message]
2024-03-30 21:44 ` [PATCH v12 00/29] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Paolo Bonzini
2024-03-30 21:44 ` Paolo Bonzini
2024-03-30 21:44 ` Paolo Bonzini
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