Re: [PATCH v7 1/4] KVM: arm64: Introduce two cache maintenance callbacks

From: Will Deacon <will@kernel.org>
To: Yanan Wang <wangyanan55@huawei.com>
Cc: Marc Zyngier <maz@kernel.org>,
	Quentin Perret <qperret@google.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Gavin Shan <gshan@redhat.com>,
	wanghaibin.wang@huawei.com, zhukeqian1@huawei.com,
	yuzenghui@huawei.com
Subject: Re: [PATCH v7 1/4] KVM: arm64: Introduce two cache maintenance callbacks
Date: Thu, 17 Jun 2021 13:38:37 +0100	[thread overview]
Message-ID: <20210617123837.GA24457@willie-the-truck> (raw)
In-Reply-To: <20210617105824.31752-2-wangyanan55@huawei.com>

On Thu, Jun 17, 2021 at 06:58:21PM +0800, Yanan Wang wrote:
> To prepare for performing CMOs for guest stage-2 in the fault handlers
> in pgtable.c, here introduce two cache maintenance callbacks in struct
> kvm_pgtable_mm_ops. We also adjust the comment alignment for the
> existing part but make no real content change at all.
> 
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> ---
>  arch/arm64/include/asm/kvm_pgtable.h | 42 +++++++++++++++++-----------
>  1 file changed, 25 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index c3674c47d48c..b6ce34aa44bb 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -27,23 +27,29 @@ typedef u64 kvm_pte_t;
>  
>  /**
>   * struct kvm_pgtable_mm_ops - Memory management callbacks.
> - * @zalloc_page:	Allocate a single zeroed memory page. The @arg parameter
> - *			can be used by the walker to pass a memcache. The
> - *			initial refcount of the page is 1.
> - * @zalloc_pages_exact:	Allocate an exact number of zeroed memory pages. The
> - *			@size parameter is in bytes, and is rounded-up to the
> - *			next page boundary. The resulting allocation is
> - *			physically contiguous.
> - * @free_pages_exact:	Free an exact number of memory pages previously
> - *			allocated by zalloc_pages_exact.
> - * @get_page:		Increment the refcount on a page.
> - * @put_page:		Decrement the refcount on a page. When the refcount
> - *			reaches 0 the page is automatically freed.
> - * @page_count:		Return the refcount of a page.
> - * @phys_to_virt:	Convert a physical address into a virtual address mapped
> - *			in the current context.
> - * @virt_to_phys:	Convert a virtual address mapped in the current context
> - *			into a physical address.
> + * @zalloc_page:		Allocate a single zeroed memory page.
> + *				The @arg parameter can be used by the walker
> + *				to pass a memcache. The initial refcount of
> + *				the page is 1.
> + * @zalloc_pages_exact:		Allocate an exact number of zeroed memory pages.
> + *				The @size parameter is in bytes, and is rounded
> + *				up to the next page boundary. The resulting
> + *				allocation is physically contiguous.
> + * @free_pages_exact:		Free an exact number of memory pages previously
> + *				allocated by zalloc_pages_exact.
> + * @get_page:			Increment the refcount on a page.
> + * @put_page:			Decrement the refcount on a page. When the
> + *				refcount reaches 0 the page is automatically
> + *				freed.
> + * @page_count:			Return the refcount of a page.
> + * @phys_to_virt:		Convert a physical address into a virtual address
> + *				mapped in the current context.
> + * @virt_to_phys:		Convert a virtual address mapped in the current
> + *				context into a physical address.
> + * @clean_invalidate_dcache:	Clean and invalidate the data cache for the
> + *				specified memory address range.

This should probably be explicit about whether this to the PoU/PoC/PoP.

Will