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From: Marc Zyngier <maz@kernel.org>
To: Michael Kelley <mikelley@microsoft.com>
Cc: <will@kernel.org>, <catalin.marinas@arm.com>,
	<mark.rutland@arm.com>, <linux-arm-kernel@lists.infradead.org>,
	<gregkh@linuxfoundation.org>, <linux-kernel@vger.kernel.org>,
	<linux-hyperv@vger.kernel.org>, <devel@linuxdriverproject.org>,
	<olaf@aepfle.de>, <apw@canonical.com>,
	vkuznets <vkuznets@redhat.com>, <jasowang@redhat.com>,
	<marcelo.cerri@canonical.com>, KY Srinivasan <kys@microsoft.com>,
	Sunil Muthuswamy <sunilmut@microsoft.com>,
	"boqun.feng" <boqun.feng@gmail.com>
Subject: Re: [PATCH v5 3/8] arm64: hyperv: Add memory alloc/free functions  for Hyper-V size pages
Date: Thu, 07 Nov 2019 15:28:49 +0109
Message-ID: <43d53ebd2637bd9106137103028a4f0e@www.loen.fr> (raw)
In-Reply-To: <1570129355-16005-4-git-send-email-mikelley@microsoft.com>

On 2019-10-03 20:12, Michael Kelley wrote:
> Add ARM64-specific code to allocate memory with HV_HYP_PAGE_SIZE
> size and alignment. These are for use when pages need to be shared
> with Hyper-V. Separate functions are needed as the page size used
> by Hyper-V may not be the same as the guest page size.  Free
> operations are rarely done, so no attempt is made to combine
> freed pages into larger chunks.
>
> This code is built only when CONFIG_HYPERV is enabled.
>
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>
> ---
>  arch/arm64/hyperv/hv_init.c    | 68
> ++++++++++++++++++++++++++++++++++++++++++
>  include/asm-generic/mshyperv.h |  5 ++++
>  2 files changed, 73 insertions(+)
>
> diff --git a/arch/arm64/hyperv/hv_init.c 
> b/arch/arm64/hyperv/hv_init.c
> index 6808bc8..9c294f6 100644
> --- a/arch/arm64/hyperv/hv_init.c
> +++ b/arch/arm64/hyperv/hv_init.c
> @@ -15,10 +15,78 @@
>  #include <linux/export.h>
>  #include <linux/mm.h>
>  #include <linux/hyperv.h>
> +#include <linux/spinlock.h>
> +#include <linux/list.h>
> +#include <linux/string.h>
>  #include <asm-generic/bug.h>
>  #include <asm/hyperv-tlfs.h>
>  #include <asm/mshyperv.h>
>
> +
> +/*
> + * Functions for allocating and freeing memory with size and
> + * alignment HV_HYP_PAGE_SIZE. These functions are needed because
> + * the guest page size may not be the same as the Hyper-V page
> + * size. And while kalloc() could allocate the memory, it does not
> + * guarantee the required alignment. So a separate small memory
> + * allocator is needed.  The free function is rarely used, so it
> + * does not try to combine freed pages into larger chunks.

Is this still needed now that kmalloc has alignment guarantees
(see 59bb47985c1d)?

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

      parent reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1570129355-16005-1-git-send-email-mikelley@microsoft.com>
     [not found] ` <1570129355-16005-3-git-send-email-mikelley@microsoft.com>
2019-11-04  4:36   ` [PATCH v5 2/8] arm64: hyperv: Add hypercall and register access functions Boqun Feng
2019-11-06 10:19   ` Marc Zyngier
     [not found]     ` <DM5PR21MB013730D09CB8BA7658DE57F7D7790@DM5PR21MB0137.namprd21.prod.outlook.com>
2019-11-07  9:10       ` Marc Zyngier
     [not found] ` <1570129355-16005-4-git-send-email-mikelley@microsoft.com>
2019-11-07 14:19   ` Marc Zyngier [this message]

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