From: Sean Christopherson <seanjc@google.com>
To: Rick P Edgecombe <rick.p.edgecombe@intel.com>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>,
Kai Huang <kai.huang@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"sean.j.christopherson@intel.com"
<sean.j.christopherson@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Yan Y Zhao <yan.y.zhao@intel.com>,
Isaku Yamahata <isaku.yamahata@intel.com>,
"tony.lindgren@linux.intel.com" <tony.lindgren@linux.intel.com>
Subject: Re: [PATCH 20/30] KVM: TDX: create/destroy VM structure
Date: Fri, 21 Feb 2025 17:38:36 -0800 [thread overview]
Message-ID: <Z7kqnDDTSlfv38Pf@google.com> (raw)
In-Reply-To: <5da952c534b68bba9fbfddf2197209cb719f5e41.camel@intel.com>
On Sat, Feb 22, 2025, Rick P Edgecombe wrote:
> On Thu, 2025-02-20 at 17:08 -0800, Sean Christopherson wrote:
> > Argh, after digging more, this isn't actually true. The separate "unload MMUs"
> > code is leftover from when KVM rather stupidly tried to free all MMU pages when
> > freeing a vCPU.
> >
> > Commit 7b53aa565084 ("KVM: Fix vcpu freeing for guest smp") "fixed" things by
> > unloading MMUs before destroying vCPUs, but the underlying problem was trying to
> > free _all_ MMU pages when destroying a single vCPU. That eventually got fixed
> > for good (haven't checked when), but the separate MMU unloading never got cleaned
> > up.
> >
> > So, scratch the mmu_destroy() idea. But I still want/need to move vCPU destruction
> > before vm_destroy.
> >
> > Now that kvm_arch_pre_destroy_vm() is a thing, one idea would be to add
> > kvm_x86_ops.pre_destroy_vm(), which would pair decently well with the existing
> > call to kvm_mmu_pre_destroy_vm().
>
> So:
> kvm_x86_call(vm_destroy)(kvm); -> tdx_mmu_release_hkid()
> kvm_destroy_vcpus(kvm); -> tdx_vcpu_free() -> reclaim
> static_call_cond(kvm_x86_vm_free)(kvm); -> reclaim
>
> To:
> (pre_destroy_vm)() -> tdx_mmu_release_hkid()
> kvm_destroy_vcpus(kvm); -> reclaim
> kvm_x86_call(vm_destroy)(kvm); -> nothing
> static_call_cond(kvm_x86_vm_free)(kvm); -> reclaim
I was thinking this last one could go away, and TDX could reclaim at vm_destroy?
Or is that not possible because it absolutely must come dead last?
> I'm not seeing a problem. We can follow up with a real check once you post the
> patches.
Ya. That ain't happening today. Got demolished but KVM-Unit-Tests. :-/
> I'm not 100% confident on the shape of the proposal. But in general if
> we can add more callbacks it seems likely that we can reproduce the current
> order. At this stage it seems safer to do that then anything more clever
next prev parent reply other threads:[~2025-02-22 1:38 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-20 17:05 [PATCH v3 00/30] TDX initialization + vCPU/VM creation Paolo Bonzini
2025-02-20 17:05 ` [PATCH 01/30] x86/virt/tdx: Add SEAMCALL wrappers for TDX KeyID management Paolo Bonzini
2025-02-20 17:05 ` [PATCH 02/30] x86/virt/tdx: Add SEAMCALL wrappers for TDX TD creation Paolo Bonzini
2025-02-20 17:05 ` [PATCH 03/30] x86/virt/tdx: Add SEAMCALL wrappers for TDX vCPU creation Paolo Bonzini
2025-02-20 17:05 ` [PATCH 04/30] x86/virt/tdx: Add SEAMCALL wrappers for TDX page cache management Paolo Bonzini
2025-02-20 17:05 ` [PATCH 05/30] x86/virt/tdx: Add SEAMCALL wrappers for TDX VM/vCPU field access Paolo Bonzini
2025-02-20 17:05 ` [PATCH 06/30] x86/virt/tdx: Add SEAMCALL wrappers for TDX flush operations Paolo Bonzini
2025-02-20 17:05 ` [PATCH 07/30] x86/virt/tdx: allocate tdx_sys_info in static memory Paolo Bonzini
2025-02-20 21:59 ` Huang, Kai
2025-02-20 23:37 ` Edgecombe, Rick P
2025-02-20 17:05 ` [PATCH 08/30] x86/virt/tdx: Read essential global metadata for KVM Paolo Bonzini
2025-02-20 17:05 ` [PATCH 09/30] x86/virt/tdx: Add tdx_guest_keyid_alloc/free() to alloc and free TDX guest KeyID Paolo Bonzini
2025-02-20 17:05 ` [PATCH 10/30] KVM: Export hardware virtualization enabling/disabling functions Paolo Bonzini
2025-02-20 17:05 ` [PATCH 11/30] KVM: VMX: Refactor VMX module init/exit functions Paolo Bonzini
2025-02-20 21:55 ` Huang, Kai
2025-02-20 17:05 ` [PATCH 12/30] KVM: VMX: Initialize TDX during KVM module load Paolo Bonzini
2025-02-20 23:27 ` Huang, Kai
2025-02-24 18:57 ` Paolo Bonzini
2025-02-24 21:31 ` Huang, Kai
2025-02-20 17:05 ` [PATCH 13/30] KVM: TDX: Get TDX global information Paolo Bonzini
2025-02-21 0:12 ` Huang, Kai
2025-02-20 17:05 ` [PATCH 14/30] KVM: TDX: Add placeholders for TDX VM/vCPU structures Paolo Bonzini
2025-02-20 17:05 ` [PATCH 15/30] KVM: TDX: Define TDX architectural definitions Paolo Bonzini
2025-02-20 17:05 ` [PATCH 16/30] KVM: TDX: Add TDX "architectural" error codes Paolo Bonzini
2025-02-20 17:05 ` [PATCH 17/30] KVM: TDX: Add helper functions to print TDX SEAMCALL error Paolo Bonzini
2025-02-20 17:05 ` [PATCH 18/30] KVM: TDX: Add place holder for TDX VM specific mem_enc_op ioctl Paolo Bonzini
2025-02-25 10:50 ` Huang, Kai
2025-02-20 17:05 ` [PATCH 19/30] KVM: TDX: Get system-wide info about TDX module on initialization Paolo Bonzini
2025-02-20 17:05 ` [PATCH 20/30] KVM: TDX: create/destroy VM structure Paolo Bonzini
2025-02-21 0:55 ` Sean Christopherson
2025-02-21 1:08 ` Sean Christopherson
2025-02-22 0:30 ` Edgecombe, Rick P
2025-02-22 1:38 ` Sean Christopherson [this message]
2025-02-24 8:32 ` Yan Zhao
2025-02-21 11:04 ` Yan Zhao
2025-02-21 19:43 ` Sean Christopherson
2025-02-21 12:25 ` Yan Zhao
2025-02-25 16:24 ` Xiaoyao Li
2025-02-20 17:05 ` [PATCH 21/30] KVM: TDX: Support per-VM KVM_CAP_MAX_VCPUS extension check Paolo Bonzini
2025-02-20 17:05 ` [PATCH 22/30] KVM: x86: expose cpuid_entry2_find for TDX Paolo Bonzini
2025-02-20 17:05 ` [PATCH 23/30] KVM: TDX: initialize VM with TDX specific parameters Paolo Bonzini
2025-02-21 2:31 ` Xiaoyao Li
2025-02-25 17:28 ` Paolo Bonzini
2025-02-20 17:05 ` [PATCH 24/30] KVM: TDX: Make pmu_intel.c ignore guest TD case Paolo Bonzini
2025-02-20 17:05 ` [PATCH 25/30] KVM: TDX: Don't offline the last cpu of one package when there's TDX guest Paolo Bonzini
2025-02-20 17:06 ` [PATCH 26/30] KVM: TDX: create/free TDX vcpu structure Paolo Bonzini
2025-02-20 17:06 ` [PATCH 27/30] KVM: TDX: Do TDX specific vcpu initialization Paolo Bonzini
2025-02-20 17:06 ` [PATCH 28/30] KVM: x86: Introduce KVM_TDX_GET_CPUID Paolo Bonzini
2025-02-20 17:06 ` [PATCH 29/30] KVM: x86/mmu: Taking guest pa into consideration when calculate tdp level Paolo Bonzini
2025-02-20 17:06 ` [PATCH 30/30] KVM: TDX: Register TDX host key IDs to cgroup misc controller Paolo Bonzini
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