From: Michael Roth <michael.roth@amd.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: <kvm@vger.kernel.org>, <linux-coco@lists.linux.dev>,
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Xu Yilun <yilun.xu@linux.intel.com>,
Binbin Wu <binbin.wu@linux.intel.com>,
Xiaoyao Li <xiaoyao.li@intel.com>
Subject: Re: [PATCH v12 11/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command
Date: Mon, 1 Apr 2024 17:22:29 -0500 [thread overview]
Message-ID: <20240401222229.qpnpozdsr6b2sntk@amd.com> (raw)
In-Reply-To: <8c3685a6-833c-4b3c-83f4-c0bd78bba36e@redhat.com>
On Sat, Mar 30, 2024 at 09:31:40PM +0100, Paolo Bonzini wrote:
> On 3/29/24 23:58, Michael Roth wrote:
Cc'ing some more TDX folks.
> > + memslot = gfn_to_memslot(kvm, params.gfn_start);
> > + if (!kvm_slot_can_be_private(memslot)) {
> > + ret = -EINVAL;
> > + goto out;
> > + }
> > +
>
> This can be moved to kvm_gmem_populate.
That does seem nicer, but I hadn't really seen that pattern for
kvm_gmem_get_pfn()/etc. so wasn't sure if that was by design or not. I
suppose in those cases the memslot is already available at the main
KVM page-fault call-sites so maybe it was just unecessary to do the
lookup internally there.
>
> > + populate_args.src = u64_to_user_ptr(params.uaddr);
>
> This is not used if !do_memcpy, and in fact src is redundant with do_memcpy.
> Overall the arguments can be "kvm, gfn, src, npages, post_populate, opaque"
> which are relatively few and do not need the struct.
This was actually a consideration for TDX that was discussed during the
"Finalizing internal guest_memfd APIs for SNP/TDX" PUCK call. In that
case, they have a TDH_MEM_PAGE_ADD seamcall that takes @src and encrypts
it, loads it into the destination page, and then maps it into SecureEPT
through a single call. So in that particular case, @src would be
initialized, but the memcpy() would be unecessary.
It's not actually clear TDX plans to use this interface. In v19 they still
used a KVM MMU hook (set_private_spte) that gets triggered through a call
to KVM_MAP_MEMORY->kvm_mmu_map_tdp_page() prior to starting the guest. But
more recent discussion[1] suggests that KVM_MAP_MEMORY->kvm_mmu_map_tdp_page()
would now only be used to create upper levels of SecureEPT, and the
actual mapping/encrypting of the leaf page would be handled by a
separate TDX-specific interface.
With that model, the potential for using kvm_gmem_populate() seemed
plausible to I was trying to make it immediately usable for that
purpose. But maybe the TDX folks can confirm whether this would be
usable for them or not. (kvm_gmem_populate was introduced here[2] for
reference/background)
-Mike
[1] https://lore.kernel.org/kvm/20240319155349.GE1645738@ls.amr.corp.intel.com/T/#m8580d8e39476be565534d6ff5f5afa295fe8d4f7
[2] https://lore.kernel.org/kvm/20240329212444.395559-3-michael.roth@amd.com/T/#m3aeba660fcc991602820d3703b1265722b871025)
>
> I'll do that when posting the next version of the patches in kvm-coco-queue.
>
> Paolo
>
next prev parent reply other threads:[~2024-04-01 22:23 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 [this message]
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
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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