linux-kernel - Re: [PATCH V1 3/6] xen/virtio: Add option to restrict memory access under Xen

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Date:   Sat, 23 Apr 2022 10:05:22 +0300
From:   Oleksandr <olekstysh@...il.com>
To:     Stefano Stabellini <sstabellini@...nel.org>
Cc:     xen-devel@...ts.xenproject.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Juergen Gross <jgross@...e.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Julien Grall <julien@....org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH V1 3/6] xen/virtio: Add option to restrict memory access
 under Xen


On 23.04.22 02:00, Stefano Stabellini wrote:

Hello Stefano


> On Fri, 22 Apr 2022, Oleksandr Tyshchenko wrote:
>> From: Juergen Gross <jgross@...e.com>
>>
>> Introduce Xen grant DMA-mapping layer which contains special DMA-mapping
>> routines for providing grant references as DMA addresses to be used by
>> frontends (e.g. virtio) in Xen guests.
>>
>> In order to support virtio in Xen guests add a config option XEN_VIRTIO
>> enabling the user to specify whether in all Xen guests virtio should
>> be able to access memory via Xen grant mappings only on the host side.
>>
>> As this also requires providing arch_has_restricted_virtio_memory_access
>> implementation, switch from a pure stub to a real function on Arm
>> and combine with existing implementation for the SEV guests on x86.
>>
>> Add the needed functionality by providing a special set of DMA ops
>> handling the needed grant operations for the I/O pages.
>>
>> Signed-off-by: Juergen Gross <jgross@...e.com>
>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
> There are a couple of minor things that checkpatch.pl reports,

Thank you for pointing this out, my fault.


>   but aside
> from those the patch looks fine to me.

good


The attached diff to be squashed for the new version. One thing remains:

checkpatch.pl says regarding drivers/xen/grant-dma-ops.c:

WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#151:
new file mode 100644


Which, I assume, this is not an issue as new file falls under XEN 
HYPERVISOR INTERFACE maintainership?

scripts/get_maintainer.pl -f drivers/xen/grant-dma-ops.c
Boris Ostrovsky <boris.ostrovsky@...cle.com> (supporter:XEN HYPERVISOR 
INTERFACE)
Juergen Gross <jgross@...e.com> (supporter:XEN HYPERVISOR INTERFACE)
Stefano Stabellini <sstabellini@...nel.org> (reviewer:XEN HYPERVISOR 
INTERFACE)
xen-devel@...ts.xenproject.org (moderated list:XEN HYPERVISOR INTERFACE)
linux-kernel@...r.kernel.org (open list)

[snip]

-- 
Regards,

Oleksandr Tyshchenko


View attachment "0001-fixup.patch" of type "text/x-patch" (3125 bytes)