From: Paolo Bonzini <pbonzini@redhat.com>
To: Erwan Velu <erwanaliasr1@gmail.com>
Cc: Erwan Velu <e.velu@criteo.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>,
"open list:KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86)"
<kvm@vger.kernel.org>,
"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] kvm: x86: Limit the number of "kvm: disabled by bios" messages
Date: Fri, 28 Feb 2020 11:37:34 +0100 [thread overview]
Message-ID: <dbcda2fb-2062-acdc-af03-fad5d667a742@redhat.com> (raw)
In-Reply-To: <20200227180047.53888-1-e.velu@criteo.com>
On 27/02/20 19:00, Erwan Velu wrote:
> In older version of systemd(219), at boot time, udevadm is called with :
> /usr/bin/udevadm trigger --type=devices --action=add"
>
> This program generates an echo "add" in /sys/devices/system/cpu/cpu<x>/uevent,
> leading to the "kvm: disabled by bios" message in case of your Bios disabled
> the virtualization extensions.
>
> On a modern system running up to 256 CPU threads, this pollutes the Kernel logs.
>
> This patch offers to ratelimit this message to avoid any userspace program triggering
> this uevent printing this message too often.
>
> This patch is only a workaround but greatly reduce the pollution without
> breaking the current behavior of printing a message if some try to instantiate
> KVM on a system that doesn't support it.
>
> Note that recent versions of systemd (>239) do not have trigger this behavior.
>
> This patch will be useful at least for some using older systemd with recent Kernels.
>
> Signed-off-by: Erwan Velu <e.velu@criteo.com>
> ---
> arch/x86/kvm/x86.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 359fcd395132..c8a90231befe 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7308,12 +7308,12 @@ int kvm_arch_init(void *opaque)
> }
>
> if (!ops->cpu_has_kvm_support()) {
> - printk(KERN_ERR "kvm: no hardware support\n");
> + pr_err_ratelimited("kvm: no hardware support\n");
> r = -EOPNOTSUPP;
> goto out;
> }
> if (ops->disabled_by_bios()) {
> - printk(KERN_ERR "kvm: disabled by bios\n");
> + pr_err_ratelimited("kvm: disabled by bios\n");
> r = -EOPNOTSUPP;
> goto out;
> }
>
Queued, thanks.
Paolo
prev parent reply other threads:[~2020-02-28 10:37 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 14:30 [PATCH] kvm: x86: Print "disabled by bios" only once per host Erwan Velu
2020-02-14 17:05 ` Sean Christopherson
2020-02-18 16:28 ` Erwan Velu
2020-02-18 18:48 ` Sean Christopherson
2020-02-19 11:19 ` Erwan Velu
2020-02-19 11:32 ` Erwan Velu
2020-02-19 17:42 ` Erwan Velu
2020-02-19 16:18 ` Sean Christopherson
2020-02-19 16:53 ` Erwan Velu
2020-02-19 17:51 ` Paolo Bonzini
2020-02-19 21:52 ` Erwan Velu
2020-02-14 17:43 ` Jim Mattson
2020-02-27 18:00 ` [PATCH v2] kvm: x86: Limit the number of "kvm: disabled by bios" messages Erwan Velu
2020-02-28 10:37 ` Paolo Bonzini [this message]
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