linux-kernel - Re: [PATCH 2/2]Add Variable Page Size and IA64 Support in Intel IOMMU: IA64 Specific Part

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:	Fri, 3 Oct 2008 09:41:42 -0600
From:	Bjorn Helgaas <bjorn.helgaas@...com>
To:	"Yu, Fenghua" <fenghua.yu@...el.com>
Cc:	"Luck, Tony" <tony.luck@...el.com>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	David Woodhouse <dwmw2@...radead.org>,
	Ingo Molnar <mingo@...e.hu>, Avi Kivity <avi@...hat.com>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>
Subject: Re: [PATCH 2/2]Add Variable Page Size and IA64 Support in Intel IOMMU: IA64 Specific Part

On Thursday 02 October 2008 11:46:04 am Yu, Fenghua wrote:
> >> --- a/arch/ia64/include/asm/cacheflush.h
> >> +++ b/arch/ia64/include/asm/cacheflush.h
> >> @@ -34,6 +34,8 @@ do {                                                \
> >>  #define flush_dcache_mmap_unlock(mapping)    do { } while (0)
> >>
> >>  extern void flush_icache_range (unsigned long start, unsigned long end);
> >> +extern void clflush_cache_range(void *addr, int size);
> >
> >This patch adds clflush_cache_range(), but it's not used anywhere.
> Clflush_cache_range() is used in __iommu_flush_cache() in include/linux/intel-iommu.h.

Oh, OK.  I didn't look hard enough to find __iommu_flush_cache()
(currently in drivers/pci/intel-iommu.c).

Architecturally, I'm surprised that ia64 would need to actually do a
cache flush.  I would think the VT-d hardware would do coherent accesses
which would make the cache flush unnecessary.

Bjorn
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/