From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: Thiago Jung Bauermann <bauerman-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
Cc: Anshuman Khandual
<anshuman.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Benjamin Herrenschmidt
<benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>,
Mike Anderson <andmike-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>,
Ram Pai <linuxram-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
Anshuman Khandual
<khandual-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Subject: Re: [RFC PATCH 10/11] powerpc/svm: Force the use of bounce buffers
Date: Fri, 24 Aug 2018 08:00:55 +0200 [thread overview]
Message-ID: <20180824060055.GB13689@lst.de> (raw)
In-Reply-To: <20180824025933.24319-11-bauerman-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
On Thu, Aug 23, 2018 at 11:59:32PM -0300, Thiago Jung Bauermann wrote:
> From: Anshuman Khandual <khandual-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
>
> SWIOTLB checks range of incoming CPU addresses to be bounced and see if the
> device can access it through it's DMA window without requiring bouncing. In
> such cases it just chooses to skip bouncing. But for cases like secure
> guests on powerpc platform all addresses need to be bounced into the shared
> pool of memory because the host cannot access it otherwise. Hence the need
> to do the bouncing is not related to device's DMA window. Hence force the
> use of bouncing by setting the swiotlb_force variable on secure guests.
>
> Signed-off-by: Anshuman Khandual <khandual-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Signed-off-by: Thiago Jung Bauermann <bauerman-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
> ---
> arch/powerpc/kernel/svm.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/powerpc/kernel/svm.c b/arch/powerpc/kernel/svm.c
> index 1af5caa955f5..f0576ad65cd0 100644
> --- a/arch/powerpc/kernel/svm.c
> +++ b/arch/powerpc/kernel/svm.c
> @@ -17,6 +17,7 @@ static int __init init_svm(void)
> return 0;
>
> ppc_swiotlb_enable = 1;
> + swiotlb_force = SWIOTLB_FORCE;
> swiotlb_update_mem_attributes();
This needs a comment.
next prev parent reply other threads:[~2018-08-24 6:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 2:59 [RFC PATCH 00/11] Secure Virtual Machine Enablement Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 01/11] powerpc/svm: Detect Secure Virtual Machine (SVM) platform Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 02/11] powerpc/svm: Select CONFIG_DMA_DIRECT_OPS and CONFIG_SWIOTLB Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 03/11] powerpc/svm: Add memory conversion (shared/secure) helper functions Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 04/11] powerpc/svm: Convert SWIOTLB buffers to shared memory Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 05/11] powerpc/svm: Don't release SWIOTLB buffers on secure guests Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 06/11] powerpc/svm: Use SWIOTLB DMA API for all virtio devices Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 07/11] powerpc/svm: Use shared memory for Debug Trace Log (DTL) Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 08/11] powerpc: Add and use LPPACA_SIZE constant Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 09/11] powerpc/svm: Use shared memory for LPPACA structures Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 10/11] powerpc/svm: Force the use of bounce buffers Thiago Jung Bauermann
[not found] ` <20180824025933.24319-11-bauerman-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
2018-08-24 6:00 ` Christoph Hellwig [this message]
2018-08-24 23:38 ` Thiago Jung Bauermann
2018-08-24 2:59 ` [RFC PATCH 11/11] powerpc/svm: Increase SWIOTLB buffer size Thiago Jung Bauermann
[not found] ` <20180824025933.24319-12-bauerman-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
2018-08-25 8:55 ` Christoph Hellwig
[not found] ` <20180824025933.24319-1-bauerman-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
2018-08-24 6:00 ` [RFC PATCH 00/11] Secure Virtual Machine Enablement Christoph Hellwig
2018-08-24 16:25 Thiago Jung Bauermann
2018-08-24 16:25 ` [RFC PATCH 10/11] powerpc/svm: Force the use of bounce buffers Thiago Jung Bauermann
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