Re: [PATCH 14/21] KVM: Move x86's version of struct kvm_mmu_memory_cache to common code

From: Marc Zyngier <maz@kernel.org>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paul Mackerras <paulus@ozlabs.org>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	David Hildenbrand <david@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
	kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
	linux-kernel@vger.kernel.org, Peter Feiner <pfeiner@google.com>,
	Peter Shier <pshier@google.com>,
	Junaid Shahid <junaids@google.com>,
	Ben Gardon <bgardon@google.com>,
	Christoffer Dall <christoffer.dall@arm.com>
Subject: Re: [PATCH 14/21] KVM: Move x86's version of struct kvm_mmu_memory_cache to common code
Date: Thu, 11 Jun 2020 07:42:35 +0000	[thread overview]
Message-ID: <f57fc7237ffba4f22042b42efb18d2e4@kernel.org> (raw)
In-Reply-To: <20200605213853.14959-15-sean.j.christopherson@intel.com>

Hi Sean,

On 2020-06-05 22:38, Sean Christopherson wrote:
> Move x86's 'struct kvm_mmu_memory_cache' to common code in anticipation
> of moving the entire x86 implementation code to common KVM and reusing
> it for arm64 and MIPS.  Add a new architecture specific asm/kvm_types.h
> to control the existence and parameters of the struct.  The new header
> is needed to avoid a chicken-and-egg problem with asm/kvm_host.h as all
> architectures define instances of the struct in their vCPU structs.
> 
> Suggested-by: Christoffer Dall <christoffer.dall@arm.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/arm64/include/asm/kvm_types.h   |  6 ++++++
>  arch/mips/include/asm/kvm_types.h    |  5 +++++
>  arch/powerpc/include/asm/kvm_types.h |  5 +++++
>  arch/s390/include/asm/kvm_types.h    |  5 +++++
>  arch/x86/include/asm/kvm_host.h      | 13 -------------
>  arch/x86/include/asm/kvm_types.h     |  7 +++++++
>  include/linux/kvm_types.h            | 19 +++++++++++++++++++
>  7 files changed, 47 insertions(+), 13 deletions(-)
>  create mode 100644 arch/arm64/include/asm/kvm_types.h
>  create mode 100644 arch/mips/include/asm/kvm_types.h
>  create mode 100644 arch/powerpc/include/asm/kvm_types.h
>  create mode 100644 arch/s390/include/asm/kvm_types.h
>  create mode 100644 arch/x86/include/asm/kvm_types.h
> 
> diff --git a/arch/arm64/include/asm/kvm_types.h
> b/arch/arm64/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..d0987007d581
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_types.h
> @@ -0,0 +1,6 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_ARM64_KVM_TYPES_H
> +#define _ASM_ARM64_KVM_TYPES_H
> +
> +#endif /* _ASM_ARM64_KVM_TYPES_H */
> +
> diff --git a/arch/mips/include/asm/kvm_types.h
> b/arch/mips/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..5efeb32a5926
> --- /dev/null
> +++ b/arch/mips/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_MIPS_KVM_TYPES_H
> +#define _ASM_MIPS_KVM_TYPES_H
> +
> +#endif /* _ASM_MIPS_KVM_TYPES_H */
> diff --git a/arch/powerpc/include/asm/kvm_types.h
> b/arch/powerpc/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..f627eceaa314
> --- /dev/null
> +++ b/arch/powerpc/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_POWERPC_KVM_TYPES_H
> +#define _ASM_POWERPC_KVM_TYPES_H
> +
> +#endif /* _ASM_POWERPC_KVM_TYPES_H */
> diff --git a/arch/s390/include/asm/kvm_types.h
> b/arch/s390/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..b66a81f8a354
> --- /dev/null
> +++ b/arch/s390/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_S390_KVM_TYPES_H
> +#define _ASM_S390_KVM_TYPES_H
> +
> +#endif /* _ASM_S390_KVM_TYPES_H */

Instead of carrying an empty include file for at least two of the 
architectures
(s390 and Power), how about having it in asm-generic, and updating
arch/$ARCH/include/asm/Kbuild to point to the generic one?

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...