kvm: exit halt polling on need_resched() as well

stable inclusion
from stable-5.10.38
commit ce7639252357be0e1f93a77abd6d81f39c800a91
bugzilla: 51875
CVE: NA

--------------------------------

commit 262de410 upstream.

single_task_running() is usually more general than need_resched()
but CFS_BANDWIDTH throttling will use resched_task() when there
is just one task to get the task to block. This was causing
long-need_resched warnings and was likely allowing VMs to
overrun their quota when halt polling.
Signed-off-by: NBen Segall <bsegall@google.com>
Signed-off-by: NVenkatesh Srinivas <venkateshs@chromium.org>
Message-Id: <20210429162233.116849-1-venkateshs@chromium.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

virt/kvm/kvm_main.c

@@ -2805,7 +2805,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 				goto out;
 			}
 			poll_end = cur = ktime_get();
-		} while (single_task_running() && ktime_before(cur, stop));
+		} while (single_task_running() && !need_resched() &&
+			 ktime_before(cur, stop));
 	}
 
 	prepare_to_rcuwait(&vcpu->wait);