Re: [PATCH v3 00/21] KVM: Cleanup and unify kvm_mmu_memory_cache usage

From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
	Marc Zyngier <maz@kernel.org>, Arnd Bergmann <arnd@arndb.de>
Cc: James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.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, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org, Ben Gardon <bgardon@google.com>,
	Peter Feiner <pfeiner@google.com>,
	Peter Shier <pshier@google.com>,
	Junaid Shahid <junaids@google.com>,
	Christoffer Dall <christoffer.dall@arm.com>
Subject: Re: [PATCH v3 00/21] KVM: Cleanup and unify kvm_mmu_memory_cache usage
Date: Thu, 9 Jul 2020 14:14:28 +0200	[thread overview]
Message-ID: <9cce79d8-bc8a-8a3a-060a-c9a882dd7e07@redhat.com> (raw)
In-Reply-To: <20200703023545.8771-1-sean.j.christopherson@intel.com>

On 03/07/20 04:35, Sean Christopherson wrote:
> The only interesting delta from v2 is that patch 18 is updated to handle
> a conflict with arm64's p4d rework.  Resolution was straightforward
> (famous last words).
> 
> 
> This series resurrects Christoffer Dall's series[1] to provide a common
> MMU memory cache implementation that can be shared by x86, arm64 and MIPS.
> 
> It also picks up a suggested change from Ben Gardon[2] to clear shadow
> page tables during initial allocation so as to avoid clearing entire
> pages while holding mmu_lock.
> 
> The front half of the patches do house cleaning on x86's memory cache
> implementation in preparation for moving it to common code, along with a
> fair bit of cleanup on the usage.  The middle chunk moves the patches to
> common KVM, and the last two chunks convert arm64 and MIPS to the common
> implementation.
> 
> Fully tested on x86 only.  Compile tested patches 14-21 on arm64, MIPS,
> s390 and PowerPC.

Queued, thanks.

Paolo

> v3:
>   - Rebased to kvm/queue, commit a037ff353ba6 ("Merge ... into HEAD")
>   - Collect more review tags. [Ben]
> 
> v2:
>   - Rebase to kvm-5.8-2, commit 49b3deaad345 ("Merge tag ...").
>   - Use an asm-generic kvm_types.h for s390 and PowerPC instead of an
>     empty arch-specific file. [Marc]
>   - Explicit document "GFP_PGTABLE_USER == GFP_KERNEL_ACCOUNT | GFP_ZERO"
>     in the arm64 conversion patch. [Marc]
>   - Collect review tags. [Ben]
> 
> Sean Christopherson (21):
>   KVM: x86/mmu: Track the associated kmem_cache in the MMU caches
>   KVM: x86/mmu: Consolidate "page" variant of memory cache helpers
>   KVM: x86/mmu: Use consistent "mc" name for kvm_mmu_memory_cache locals
>   KVM: x86/mmu: Remove superfluous gotos from mmu_topup_memory_caches()
>   KVM: x86/mmu: Try to avoid crashing KVM if a MMU memory cache is empty
>   KVM: x86/mmu: Move fast_page_fault() call above
>     mmu_topup_memory_caches()
>   KVM: x86/mmu: Topup memory caches after walking GVA->GPA
>   KVM: x86/mmu: Clean up the gorilla math in mmu_topup_memory_caches()
>   KVM: x86/mmu: Separate the memory caches for shadow pages and gfn
>     arrays
>   KVM: x86/mmu: Make __GFP_ZERO a property of the memory cache
>   KVM: x86/mmu: Zero allocate shadow pages (outside of mmu_lock)
>   KVM: x86/mmu: Skip filling the gfn cache for guaranteed direct MMU
>     topups
>   KVM: x86/mmu: Prepend "kvm_" to memory cache helpers that will be
>     global
>   KVM: Move x86's version of struct kvm_mmu_memory_cache to common code
>   KVM: Move x86's MMU memory cache helpers to common KVM code
>   KVM: arm64: Drop @max param from mmu_topup_memory_cache()
>   KVM: arm64: Use common code's approach for __GFP_ZERO with memory
>     caches
>   KVM: arm64: Use common KVM implementation of MMU memory caches
>   KVM: MIPS: Drop @max param from mmu_topup_memory_cache()
>   KVM: MIPS: Account pages used for GPA page tables
>   KVM: MIPS: Use common KVM implementation of MMU memory caches
> 
>  arch/arm64/include/asm/kvm_host.h  |  11 ---
>  arch/arm64/include/asm/kvm_types.h |   8 ++
>  arch/arm64/kvm/arm.c               |   2 +
>  arch/arm64/kvm/mmu.c               |  56 +++----------
>  arch/mips/include/asm/kvm_host.h   |  11 ---
>  arch/mips/include/asm/kvm_types.h  |   7 ++
>  arch/mips/kvm/mmu.c                |  44 ++--------
>  arch/powerpc/include/asm/Kbuild    |   1 +
>  arch/s390/include/asm/Kbuild       |   1 +
>  arch/x86/include/asm/kvm_host.h    |  14 +---
>  arch/x86/include/asm/kvm_types.h   |   7 ++
>  arch/x86/kvm/mmu/mmu.c             | 129 +++++++++--------------------
>  arch/x86/kvm/mmu/paging_tmpl.h     |  10 +--
>  include/asm-generic/kvm_types.h    |   5 ++
>  include/linux/kvm_host.h           |   7 ++
>  include/linux/kvm_types.h          |  19 +++++
>  virt/kvm/kvm_main.c                |  55 ++++++++++++
>  17 files changed, 176 insertions(+), 211 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/x86/include/asm/kvm_types.h
>  create mode 100644 include/asm-generic/kvm_types.h
> 