From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: kvm@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
Wanpeng Li <wanpengli@tencent.com>,
"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<linux-kernel@vger.kernel.org>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Vitaly Kuznetsov <vkuznets@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Jim Mattson <jmattson@google.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 2/2] KVM: nVMX: fix for disappearing L1->L2 event injection on L1 migration
Date: Wed, 6 Jan 2021 10:17:58 -0800 [thread overview]
Message-ID: <X/X+1q6H/q1Ez6zE@google.com> (raw)
In-Reply-To: <20210106105306.450602-3-mlevitsk@redhat.com>
On Wed, Jan 06, 2021, Maxim Levitsky wrote:
> If migration happens while L2 entry with an injected event to L2 is pending,
> we weren't including the event in the migration state and it would be
> lost leading to L2 hang.
But the injected event should still be in vmcs12 and KVM_STATE_NESTED_RUN_PENDING
should be set in the migration state, i.e. it should naturally be copied to
vmcs02 and thus (re)injected by vmx_set_nested_state(). Is nested_run_pending
not set? Is the info in vmcs12 somehow lost? Or am I off in left field...
> Fix this by queueing the injected event in similar manner to how we queue
> interrupted injections.
>
> This can be reproduced by running an IO intense task in L2,
> and repeatedly migrating the L1.
>
> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
> arch/x86/kvm/vmx/nested.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index e2f26564a12de..2ea0bb14f385f 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2355,12 +2355,12 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
> * Interrupt/Exception Fields
> */
> if (vmx->nested.nested_run_pending) {
> - vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
> - vmcs12->vm_entry_intr_info_field);
> - vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE,
> - vmcs12->vm_entry_exception_error_code);
> - vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
> - vmcs12->vm_entry_instruction_len);
> + if ((vmcs12->vm_entry_intr_info_field & VECTORING_INFO_VALID_MASK))
> + vmx_process_injected_event(&vmx->vcpu,
> + vmcs12->vm_entry_intr_info_field,
> + vmcs12->vm_entry_instruction_len,
> + vmcs12->vm_entry_exception_error_code);
> +
> vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
> vmcs12->guest_interruptibility_info);
> vmx->loaded_vmcs->nmi_known_unmasked =
> --
> 2.26.2
>
next prev parent reply other threads:[~2021-01-06 18:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 10:53 [PATCH 0/2] RFC: VMX: fix for disappearing L1->L2 event injection on L1 migration Maxim Levitsky
2021-01-06 10:53 ` [PATCH 1/2] KVM: VMX: create vmx_process_injected_event Maxim Levitsky
2021-01-06 10:53 ` [PATCH 2/2] KVM: nVMX: fix for disappearing L1->L2 event injection on L1 migration Maxim Levitsky
2021-01-06 18:17 ` Sean Christopherson [this message]
2021-01-07 2:38 ` Maxim Levitsky
2021-01-07 9:41 ` Maxim Levitsky
2021-01-06 18:07 ` [PATCH 0/2] RFC: VMX: " Sean Christopherson
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