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From: Venkatesh Srinivas <venkateshs@chromium.org>
To: kvm@vger.kernel.org, dmatlack@google.com, pbonzini@redhat.com
Cc: Venkatesh Srinivas <venkateshs@chromium.org>
Subject: [PATCH] kvm: Cap halt polling at kvm->max_halt_poll_ns
Date: Thu,  6 May 2021 15:24:43 +0000	[thread overview]
Message-ID: <20210506152442.4010298-1-venkateshs@chromium.org> (raw)

From: David Matlack <dmatlack@google.com>

When growing halt-polling, there is no check that the poll time exceeds
the per-VM limit. It's possible for vcpu->halt_poll_ns to grow past
kvm->max_halt_poll_ns and stay there until a halt which takes longer
than kvm->halt_poll_ns.

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Venkatesh Srinivas <venkateshs@chromium.org>
---
 virt/kvm/kvm_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2799c6660cce..120817c5f271 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2893,8 +2893,8 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
 	if (val < grow_start)
 		val = grow_start;
 
-	if (val > halt_poll_ns)
-		val = halt_poll_ns;
+	if (val > vcpu->kvm->max_halt_poll_ns)
+		val = vcpu->kvm->max_halt_poll_ns;
 
 	vcpu->halt_poll_ns = val;
 out:
-- 
2.31.1.607.g51e8a6a459-goog


             reply	other threads:[~2021-05-06 15:25 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 15:24 Venkatesh Srinivas [this message]
2021-05-06 16:13 ` [PATCH] kvm: Cap halt polling at kvm->max_halt_poll_ns Sean Christopherson
2021-05-06 16:30   ` David Matlack
2021-05-06 17:41     ` Sean Christopherson

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