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From: Sean Christopherson <seanjc@google.com>
To: Marc Zyngier <maz@kernel.org>,
	Huacai Chen <chenhuacai@kernel.org>,
	Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
	Paul Mackerras <paulus@ozlabs.org>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	David Hildenbrand <david@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
	kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
	linux-kernel@vger.kernel.org, David Matlack <dmatlack@google.com>,
	Jing Zhang <jingzhangos@google.com>
Subject: [PATCH 13/14] KVM: x86: Directly block (instead of "halting") UNINITIALIZED vCPUs
Date: Fri, 24 Sep 2021 17:55:27 -0700	[thread overview]
Message-ID: <20210925005528.1145584-14-seanjc@google.com> (raw)
In-Reply-To: <20210925005528.1145584-1-seanjc@google.com>

Go directly to kvm_vcpu_block() when handling the case where userspace
attempts to run an UNINITIALIZED vCPU.  The vCPU isn't halted and its time
spent in limbo arguably should not be factored into halt-polling as the
behavior of the VM at this point is not at all indicative of the behavior
of the VM once it is up and running, i.e. executing HLT in idle tasks.

Note, because this case is encountered only on the first run of an AP vCPU,
vcpu->halt_poll_ns is guaranteed to be '0', and so KVM will not attempt
halt-polling, i.e. this really only affects the post-block bookkeeping.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0d71c73a61bb..b444f9315766 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10127,7 +10127,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 			r = -EINTR;
 			goto out;
 		}
-		kvm_vcpu_halt(vcpu);
+		kvm_vcpu_block(vcpu);
 		if (kvm_apic_accept_events(vcpu) < 0) {
 			r = 0;
 			goto out;
-- 
2.33.0.685.g46640cef36-goog


  parent reply	other threads:[~2021-09-25  0:57 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-25  0:55 [PATCH 00/14] KVM: Halt-polling fixes, cleanups and a new stat Sean Christopherson
2021-09-25  0:55 ` [PATCH 01/14] KVM: s390: Ensure kvm_arch_no_poll() is read once when blocking vCPU Sean Christopherson
2021-09-27  6:54   ` Christian Borntraeger
2021-09-25  0:55 ` [PATCH 02/14] KVM: Update halt-polling stats if and only if halt-polling was attempted Sean Christopherson
2021-09-28 18:57   ` David Matlack
2021-09-25  0:55 ` [PATCH 03/14] KVM: Refactor and document halt-polling stats update helper Sean Christopherson
2021-09-28 19:01   ` David Matlack
2021-09-25  0:55 ` [PATCH 04/14] KVM: Reconcile discrepancies in halt-polling stats Sean Christopherson
2021-09-28 21:26   ` David Matlack
2021-09-25  0:55 ` [PATCH 05/14] KVM: s390: Clear valid_wakeup in kvm_s390_handle_wait(), not in arch hook Sean Christopherson
2021-09-27  6:58   ` Christian Borntraeger
2021-09-25  0:55 ` [PATCH 06/14] KVM: Drop obsolete kvm_arch_vcpu_block_finish() Sean Christopherson
2021-09-27  6:58   ` Christian Borntraeger
2021-09-28 21:28   ` David Matlack
2021-09-25  0:55 ` [PATCH 07/14] KVM: Don't block+unblock when halt-polling is successful Sean Christopherson
2021-09-25  9:50   ` Marc Zyngier
2021-09-26  6:27     ` Paolo Bonzini
2021-09-26  9:02       ` Marc Zyngier
2021-09-27 17:28         ` Sean Christopherson
2021-09-28  9:24           ` Marc Zyngier
2021-09-28 16:21             ` Sean Christopherson
2021-09-30  9:36               ` Marc Zyngier
2021-09-25  0:55 ` [PATCH 08/14] KVM: x86: Tweak halt emulation helper names to free up kvm_vcpu_halt() Sean Christopherson
2021-09-28 21:59   ` David Matlack
2021-09-25  0:55 ` [PATCH 09/14] KVM: Rename kvm_vcpu_block() => kvm_vcpu_halt() Sean Christopherson
2021-09-27  7:06   ` Christian Borntraeger
2021-09-28 22:01   ` David Matlack
2021-09-25  0:55 ` [PATCH 10/14] KVM: Split out a kvm_vcpu_block() helper from kvm_vcpu_halt() Sean Christopherson
2021-09-27  7:41   ` Christian Borntraeger
2021-09-28 22:03   ` David Matlack
2021-09-25  0:55 ` [PATCH 11/14] KVM: stats: Add stat to detect if vcpu is currently blocking Sean Christopherson
2021-09-28 22:04   ` David Matlack
2021-09-25  0:55 ` [PATCH 12/14] KVM: Don't redo ktime_get() when calculating halt-polling stop/deadline Sean Christopherson
2021-09-28 22:08   ` David Matlack
2021-09-25  0:55 ` Sean Christopherson [this message]
2021-09-28 22:12   ` [PATCH 13/14] KVM: x86: Directly block (instead of "halting") UNINITIALIZED vCPUs David Matlack
2021-09-25  0:55 ` [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Sean Christopherson
2021-09-28 22:14   ` David Matlack
2021-09-27  7:22 ` disabling halt polling broken? (was Re: [PATCH 00/14] KVM: Halt-polling fixes, cleanups and a new stat) Christian Borntraeger
2021-09-27 14:59   ` Sean Christopherson
2021-09-27 15:03     ` Paolo Bonzini
2021-09-27 15:15       ` Sean Christopherson
2021-09-27 15:16       ` Christian Borntraeger
2021-09-27 16:58         ` David Matlack
2021-09-29  6:56           ` Christian Borntraeger
2021-09-27 17:24         ` Paolo Bonzini
2021-09-27 17:33           ` Sean Christopherson
2022-11-15  3:28             ` wangyanan (Y)
2022-11-16 17:19               ` David Matlack
2022-11-18  2:29                 ` wangyanan (Y)

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