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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Maxim Levitsky <mlevitsk@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH v3 00/11] KVM: nVMX: Fixes for nested state migration when eVMCS is in use
Date: Thu, 10 Jun 2021 16:29:37 +0200	[thread overview]
Message-ID: <87mtrxyer2.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20210526132026.270394-1-vkuznets@redhat.com>

Vitaly Kuznetsov <vkuznets@redhat.com> writes:

> Changes since v2:
> - 'KVM: nVMX: Use '-1' in 'hv_evmcs_vmptr' to indicate that eVMCS is not in
>  use'/ 'KVM: nVMX: Introduce 'EVMPTR_MAP_PENDING' post-migration state'
>  patches instead of 'KVM: nVMX: Introduce nested_evmcs_is_used()' [Paolo]
> - 'KVM: nVMX: Don't set 'dirty_vmcs12' flag on enlightened VMPTRLD' patch
>  added [Max]
> - 'KVM: nVMX: Release eVMCS when enlightened VMENTRY was disabled' patch
>   added.
> - 'KVM: nVMX: Make copy_vmcs12_to_enlightened()/copy_enlightened_to_vmcs12()
>  return 'void'' patch added [Paolo]
> - R-b tags added [Max]
>
> Original description:
>
> Commit f5c7e8425f18 ("KVM: nVMX: Always make an attempt to map eVMCS after
> migration") fixed the most obvious reason why Hyper-V on KVM (e.g. Win10
>  + WSL2) was crashing immediately after migration. It was also reported
> that we have more issues to fix as, while the failure rate was lowered 
> signifincatly, it was still possible to observe crashes after several
> dozens of migration. Turns out, the issue arises when we manage to issue
> KVM_GET_NESTED_STATE right after L2->L2 VMEXIT but before L1 gets a chance
> to run. This state is tracked with 'need_vmcs12_to_shadow_sync' flag but
> the flag itself is not part of saved nested state. A few other less 
> significant issues are fixed along the way.
>
> While there's no proof this series fixes all eVMCS related problems,
> Win10+WSL2 was able to survive 3333 (thanks, Max!) migrations without
> crashing in testing.
>
> Patches are based on the current kvm/next tree.

Paolo, Max,

Just to double-check: are we good here? I know there are more
improvements/ideas to explore but I'd like to treat this patchset as a
set of fixes, it would be unfortunate if we miss 5.14.

-- 
Vitaly


  parent reply	other threads:[~2021-06-10 14:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-26 13:20 [PATCH v3 00/11] KVM: nVMX: Fixes for nested state migration when eVMCS is in use Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 01/11] KVM: nVMX: Use '-1' in 'hv_evmcs_vmptr' to indicate that eVMCS is not " Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 02/11] KVM: nVMX: Don't set 'dirty_vmcs12' flag on enlightened VMPTRLD Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 03/11] KVM: nVMX: Release eVMCS when enlightened VMENTRY was disabled Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 04/11] KVM: nVMX: Make copy_vmcs12_to_enlightened()/copy_enlightened_to_vmcs12() return 'void' Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 05/11] KVM: nVMX: Introduce 'EVMPTR_MAP_PENDING' post-migration state Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 06/11] KVM: nVMX: Release enlightened VMCS on VMCLEAR Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 07/11] KVM: nVMX: Ignore 'hv_clean_fields' data when eVMCS data is copied in vmx_get_nested_state() Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 08/11] KVM: nVMX: Force enlightened VMCS sync from nested_vmx_failValid() Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 09/11] KVM: nVMX: Reset eVMCS clean fields data from prepare_vmcs02() Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 10/11] KVM: nVMX: Request to sync eVMCS from VMCS12 after migration Vitaly Kuznetsov
2021-05-26 13:20 ` [PATCH v3 11/11] KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never lost Vitaly Kuznetsov
2021-06-10 14:29 ` Vitaly Kuznetsov [this message]
2021-06-10 15:31   ` [PATCH v3 00/11] KVM: nVMX: Fixes for nested state migration when eVMCS is in use Paolo Bonzini

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