From: Sean Christopherson <seanjc@google.com>
To: Juergen Gross <jgross@suse.com>
Cc: kvm@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
Paolo Bonzini <pbonzini@redhat.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>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v3 4/4] x86/kvm: add boot parameter for setting max number of vcpus per guest
Date: Thu, 18 Nov 2021 15:46:35 +0000 [thread overview]
Message-ID: <YZZ1W+YxagvG1EMM@google.com> (raw)
In-Reply-To: <d5c57c27-e237-ef84-96c7-f50619597023@suse.com>
On Thu, Nov 18, 2021, Juergen Gross wrote:
> On 18.11.21 16:05, Sean Christopherson wrote:
> > Which is a good segue into pointing out that if a module param is added, it needs
> > to be sanity checked against a KVM-defined max. The admin may be trusted to some
> > extent, but there is zero reason to let userspace set max_vcspus to 4 billion.
> > At that point, it really is just a param vs. capability question.
>
> I agree. Capping it at e.g. 65536 would probably be a good idea.
Any reason to choose 65536 in particular? Why not cap it at the upper limit of
NR_CPUS_RANGE_END / MAXSMP, which is currently 8192?
prev parent reply other threads:[~2021-11-18 15:46 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-16 14:10 [PATCH v3 0/4] x86/kvm: add boot parameters for max vcpu configs Juergen Gross
2021-11-16 14:10 ` [PATCH v3 1/4] x86/kvm: add boot parameter for adding vcpu-id bits Juergen Gross
2021-11-17 6:59 ` Juergen Gross
2021-11-17 23:46 ` Sean Christopherson
2021-11-18 7:45 ` Juergen Gross
2021-11-18 15:09 ` Sean Christopherson
2021-11-18 15:19 ` Juergen Gross
2021-11-17 23:44 ` Sean Christopherson
2021-11-18 7:44 ` Juergen Gross
2021-11-16 14:10 ` [PATCH v3 2/4] x86/kvm: introduce a per cpu vcpu mask Juergen Gross
2021-11-16 14:10 ` [PATCH v3 3/4] x86/kvm: add max number of vcpus for hyperv emulation Juergen Gross
2021-11-17 20:50 ` Sean Christopherson
2021-11-18 7:43 ` Juergen Gross
2021-11-18 14:49 ` Sean Christopherson
2021-11-18 15:24 ` Juergen Gross
2021-11-18 16:12 ` Sean Christopherson
2021-11-16 14:10 ` [PATCH v3 4/4] x86/kvm: add boot parameter for setting max number of vcpus per guest Juergen Gross
2021-11-17 20:57 ` Sean Christopherson
2021-11-18 7:16 ` Juergen Gross
2021-11-18 15:05 ` Sean Christopherson
2021-11-18 15:15 ` Juergen Gross
2021-11-18 15:32 ` Sean Christopherson
2021-11-18 16:19 ` Juergen Gross
2021-11-18 15:46 ` Sean Christopherson [this message]
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