Re: [PATCH 0/5] KVM: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS and re-purpose it on x86

From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>, kvm@vger.kernel.org
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Eduardo Habkost <ehabkost@redhat.com>,
	Marc Zyngier <maz@kernel.org>, Andrew Jones <drjones@redhat.com>,
	Huacai Chen <chenhuacai@kernel.org>,
	Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
	Anup Patel <anup.patel@wdc.com>,
	Paul Mackerras <paulus@ozlabs.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Christian Borntraeger <borntraeger@de.ibm.com>
Subject: Re: [PATCH 0/5] KVM: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS and re-purpose it on x86
Date: Thu, 11 Nov 2021 17:32:00 +0100	[thread overview]
Message-ID: <4a3c7be7-12fa-6e47-64eb-02e6c5be5dbc@redhat.com> (raw)
In-Reply-To: <20211111162746.100598-1-vkuznets@redhat.com>

On 11/11/21 17:27, Vitaly Kuznetsov wrote:
> This is a comtinuation of "KVM: x86: Drop arbitraty KVM_SOFT_MAX_VCPUS"
> (https://lore.kernel.org/kvm/20211111134733.86601-1-vkuznets@redhat.com/)
> work.
> 
> 1) Enforce KVM_CAP_NR_VCPUS <= KVM_CAP_MAX_VCPUS rule on all
>   architectures. [Sean Christopherson]
> 2) Make KVM_CAP_NR_VCPUS return num_online_cpus() and not an arbitrary
>   value of '710' on x86.
> 
> Everything but x86 was only 'eyeball tested', the change is trivial
> but sorry in advance if I screwed up)

Christian, can you look at this for s390?  Returning a fixed value seems 
wrong for KVM_CAP_NR_VCPUS.

Thanks,

Paolo

> Vitaly Kuznetsov (5):
>    KVM: arm64: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
>    KVM: MIPS: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
>    KVM: PPC: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
>    KVM: RISC-V: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
>    KVM: x86: Drop arbitraty KVM_SOFT_MAX_VCPUS
> 
>   arch/arm64/kvm/arm.c            | 7 ++++++-
>   arch/mips/kvm/mips.c            | 2 +-
>   arch/powerpc/kvm/powerpc.c      | 4 ++--
>   arch/riscv/kvm/vm.c             | 2 +-
>   arch/x86/include/asm/kvm_host.h | 1 -
>   arch/x86/kvm/x86.c              | 2 +-
>   6 files changed, 11 insertions(+), 7 deletions(-)
> 