From: Maxim Levitsky <mlevitsk@redhat.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Li RongQing <lirongqing@baidu.com>
Subject: Re: [PATCH 19/19] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu"
Date: Wed, 31 Aug 2022 09:07:11 +0300 [thread overview]
Message-ID: <fd349966a87ef3cb93fe1670e91cf6d2142ed442.camel@redhat.com> (raw)
In-Reply-To: <20220831003506.4117148-20-seanjc@google.com>
On Wed, 2022-08-31 at 00:35 +0000, Sean Christopherson wrote:
> Turns out that some warnings exist for good reasons. Restore the warning
> in avic_vcpu_load() that guards against calling avic_vcpu_load() on a
> running vCPU now that KVM avoids doing so when switching between x2APIC
> and xAPIC. The entire point of the WARN is to highlight that KVM should
> not be reloading an AVIC.
>
> Opportunistically convert the WARN_ON() to WARN_ON_ONCE() to avoid
> spamming the kernel if it does fire.
>
> This reverts commit c0caeee65af3944b7b8abbf566e7cc1fae15c775.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/svm/avic.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index b2033a56010c..3c300113d40b 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -1080,6 +1080,7 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> return;
>
> entry = READ_ONCE(*(svm->avic_physical_id_cache));
> + WARN_ON_ONCE(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);
>
> entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
> entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
Note that this warning was removed because it would trigger wheh x2avic code would switch
between xapic and x2apic.
I do agree 100% that this warning is useful.
Best regards,
Maxim Levitsky
next prev parent reply other threads:[~2022-08-31 6:07 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 0:34 [PATCH 00/19] KVM: x86: AVIC and local APIC fixes+cleanups Sean Christopherson
2022-08-31 0:34 ` [PATCH 01/19] KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid target Sean Christopherson
2022-08-31 9:18 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 02/19] KVM: SVM: Don't put/load AVIC when setting virtual APIC mode Sean Christopherson
2022-08-31 9:24 ` Maxim Levitsky
2022-08-31 16:33 ` Sean Christopherson
2022-08-31 0:34 ` [PATCH 03/19] Revert "KVM: SVM: Introduce hybrid-AVIC mode" Sean Christopherson
2022-08-31 5:59 ` Maxim Levitsky
2022-08-31 6:45 ` Maxim Levitsky
2022-08-31 16:29 ` Sean Christopherson
2022-08-31 17:46 ` Maxim Levitsky
2022-08-31 17:58 ` Jim Mattson
2022-08-31 18:01 ` Maxim Levitsky
2022-08-31 19:12 ` Sean Christopherson
2022-09-01 10:25 ` Maxim Levitsky
2022-09-01 11:47 ` Jim Mattson
2022-09-01 13:29 ` Sean Christopherson
2022-09-01 13:53 ` Sean Christopherson
2022-09-01 15:08 ` Sean Christopherson
2022-08-31 16:19 ` Sean Christopherson
2022-08-31 17:47 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 04/19] KVM: SVM: Replace "avic_mode" enum with "x2avic_enabled" boolean Sean Christopherson
2022-08-31 9:36 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 05/19] KVM: SVM: Compute dest based on sender's x2APIC status for AVIC kick Sean Christopherson
2022-08-31 9:38 ` Maxim Levitsky
2022-09-01 2:56 ` Li,Rongqing
2022-08-31 0:34 ` [PATCH 06/19] KVM: SVM: Get x2APIC logical dest bitmap from ICRH[15:0], not ICHR[31:16] Sean Christopherson
2022-08-31 6:09 ` Maxim Levitsky
2022-08-31 9:43 ` Maxim Levitsky
2022-08-31 16:35 ` Sean Christopherson
2022-08-31 18:18 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 07/19] KVM: SVM: Drop buggy and redundant AVIC "single logical dest" check Sean Christopherson
2022-08-31 6:19 ` Maxim Levitsky
2022-08-31 16:37 ` Sean Christopherson
2022-08-31 18:10 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 08/19] KVM: SVM: Remove redundant cluster calculation that also creates a shadow Sean Christopherson
2022-08-31 10:19 ` Maxim Levitsky
2022-09-01 20:02 ` Sean Christopherson
2022-08-31 0:34 ` [PATCH 09/19] KVM: SVM: Drop duplicate calcuation of AVIC/x2AVIC "logical index" Sean Christopherson
2022-08-31 0:34 ` [PATCH 10/19] KVM: SVM: Document that vCPU ID == APIC ID in AVIC kick fastpatch Sean Christopherson
2022-08-31 10:22 ` Maxim Levitsky
2022-08-31 16:16 ` Sean Christopherson
2022-08-31 17:49 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 11/19] KVM: SVM: Add helper to perform final AVIC "kick" of single vCPU Sean Christopherson
2022-08-31 10:25 ` Maxim Levitsky
2022-08-31 15:08 ` Sean Christopherson
2022-08-31 18:12 ` Maxim Levitsky
2022-08-31 0:34 ` [PATCH 12/19] KVM: x86: Disable APIC logical map if logical ID covers multiple MDAs Sean Christopherson
2022-08-31 13:23 ` Maxim Levitsky
2022-08-31 0:35 ` [PATCH 13/19] KVM: x86: Disable APIC logical map if vCPUs are aliased in logical mode Sean Christopherson
2022-08-31 13:24 ` Maxim Levitsky
2022-08-31 0:35 ` [PATCH 14/19] KVM: x86: Honor architectural behavior for aliased 8-bit APIC IDs Sean Christopherson
2022-08-31 13:37 ` Maxim Levitsky
2022-08-31 16:41 ` Sean Christopherson
2022-08-31 17:51 ` Maxim Levitsky
2022-08-31 0:35 ` [PATCH 15/19] KVM: x86: Explicitly skip optimized logical map setup if vCPU's LDR==0 Sean Christopherson
2022-08-31 13:41 ` Maxim Levitsky
2022-08-31 16:47 ` Sean Christopherson
2022-08-31 0:35 ` [PATCH 16/19] KVM: x86: Explicitly track all possibilities for APIC map's logical modes Sean Christopherson
2022-08-31 13:43 ` Maxim Levitsky
2022-08-31 16:56 ` Sean Christopherson
2022-08-31 17:53 ` Maxim Levitsky
2022-09-16 18:58 ` Sean Christopherson
2022-08-31 18:42 ` Maxim Levitsky
2022-08-31 19:17 ` Sean Christopherson
2022-08-31 0:35 ` [PATCH 17/19] KVM: SVM: Handle multiple logical targets in AVIC kick fastpath Sean Christopherson
2022-08-31 13:57 ` Maxim Levitsky
2022-08-31 18:19 ` Sean Christopherson
2022-08-31 18:25 ` Maxim Levitsky
2022-08-31 0:35 ` [PATCH 18/19] KVM: SVM: Ignore writes to Remote Read Data on AVIC write traps Sean Christopherson
2022-08-31 10:40 ` Maxim Levitsky
2022-08-31 0:35 ` [PATCH 19/19] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu" Sean Christopherson
2022-08-31 6:07 ` Maxim Levitsky [this message]
2022-08-31 7:03 ` Maxim Levitsky
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