linux-kernel - Re: [PATCH v2 10/11] xen/arm: introduce phys/dma translations in xen_dma_sync_for

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 8 Jun 2020 00:12:21 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Stefano Stabellini <sstabellini@...nel.org>
Cc:     jgross@...e.com, boris.ostrovsky@...cle.com,
        konrad.wilk@...cle.com, xen-devel@...ts.xenproject.org,
        linux-kernel@...r.kernel.org, tamas@...engyel.com,
        roman@...eda.com,
        Stefano Stabellini <stefano.stabellini@...inx.com>
Subject: Re: [PATCH v2 10/11] xen/arm: introduce phys/dma translations in
 xen_dma_sync_for_*

On Wed, Jun 03, 2020 at 03:22:46PM -0700, Stefano Stabellini wrote:
> From: Stefano Stabellini <stefano.stabellini@...inx.com>
> 
> xen_dma_sync_for_cpu, xen_dma_sync_for_device, xen_arch_need_swiotlb are
> getting called passing dma addresses. On some platforms dma addresses
> could be different from physical addresses. Before doing any operations
> on these addresses we need to convert them back to physical addresses
> using dma_to_phys.
> 
> Add dma_to_phys calls to xen_dma_sync_for_cpu, xen_dma_sync_for_device,
> and xen_arch_need_swiotlb.
> 
> dma_cache_maint is fixed by the next patch.

The calling conventions because really weird now because
xen_dma_sync_for_{device,cpu} already get both a phys_addr_t and
a dma_addr_t.  

> 
> -	if (pfn_valid(PFN_DOWN(handle)))
> +	if (pfn_valid(PFN_DOWN(dma_to_phys(dev, handle))))

But here we translate the dma address to a phys addr

>  		arch_sync_dma_for_cpu(paddr, size, dir);

While this still uses the passed in paddr.  I think the uses of
addresses in this code really needs a major rethink.