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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: Like Xu <like.xu.linux@gmail.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: x86/svm: Add module param to control PMU virtualization
Date: Sat, 11 Dec 2021 03:15:25 +0100	[thread overview]
Message-ID: <438d42de-78e1-0ce9-6a06-38194de4abd4@redhat.com> (raw)
In-Reply-To: <CALMp9eRA8hw9zVEwnZEX56Gao-MibX5A+XXYS-n-+X0BkhrSvQ@mail.gmail.com>

On 12/10/21 20:25, Jim Mattson wrote:
> In the long run, I'd like to be able to override this system-wide
> setting on a per-VM basis, for VMs that I trust. (Of course, this
> implies that I trust the userspace process as well.)
> 
> How would you feel if we were to add a kvm ioctl to override this
> setting, for a particular VM, guarded by an appropriate permissions
> check, like capable(CAP_SYS_ADMIN) or capable(CAP_SYS_MODULE)?

What's the rationale for guarding this with a capability check?  IIRC 
you don't have such checks for perf_event_open (apart for getting kernel 
addresses, which is not a problem for virtualization).

Paolo

  reply	other threads:[~2021-12-11  2:15 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17  8:03 [PATCH] KVM: x86/svm: Add module param to control PMU virtualization Like Xu
2021-11-18 13:25 ` Paolo Bonzini
2021-12-10 19:25   ` Jim Mattson
2021-12-11  2:15     ` Paolo Bonzini [this message]
2021-12-11  3:48       ` Jim Mattson
2022-01-09  1:23         ` Jim Mattson
2022-01-10  6:23           ` Like Xu
2022-01-10 18:13             ` Jim Mattson
2022-01-11  2:11               ` Like Xu
2022-01-11  3:24                 ` Jim Mattson
2022-01-11  6:18                   ` Like Xu
2022-01-11  7:25                     ` Jim Mattson
2022-01-15  1:26   ` Jim Mattson
2022-01-17  2:33     ` Like Xu
2022-01-17  8:36       ` Paolo Bonzini

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