From: Pavel Fedin <p.fedin@samsung.com>
To: 'Alex Williamson' <alex.williamson@redhat.com>,
'Peter Maydell' <peter.maydell@linaro.org>
Cc: 'QEMU Developers' <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] vfio: Align iova also to IOMMU page size
Date: Mon, 07 Dec 2015 13:53:41 +0300 [thread overview]
Message-ID: <015101d130dd$8993b740$9cbb25c0$@samsung.com> (raw)
In-Reply-To: <1449165536.15753.214.camel@redhat.com>
Hello!
> TAGET_PAGE_ALIGN tells us that it *could* be a valid DMA target though.
> The VM model is capable of using that as a page size, which means we
> assume it is and want to generate a fault.
We seem to have looped back. So...
It is possible to fix this according to this assumption. In this case we would need to make TARGET_PAGE_BITS a variable. If we are emulating ancient armv5te, it will be set to 10. For modern targets, ARMv6 and newer, it will be 12.
Peter, would you ACK this approach? BTW, we even have a kind of hack in target-arm/cpu.h:
--- cut ---
#if defined(CONFIG_USER_ONLY)
#define TARGET_PAGE_BITS 12
#else
/* The ARM MMU allows 1k pages. */
/* ??? Linux doesn't actually use these, and they're deprecated in recent
architecture revisions. Maybe a configure option to disable them. */
#define TARGET_PAGE_BITS 10
#endif
--- cut ---
Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia
next prev parent reply other threads:[~2015-12-07 10:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-17 7:46 [Qemu-devel] [PATCH] vfio: Align iova also to IOMMU page size Pavel Fedin
2015-11-18 22:04 ` Alex Williamson
2015-11-19 10:29 ` Pavel Fedin
2015-11-19 23:33 ` Alex Williamson
2015-11-24 15:24 ` Pavel Fedin
2015-12-02 19:40 ` Alex Williamson
2015-12-03 9:02 ` Pavel Fedin
2015-12-03 16:26 ` Alex Williamson
2015-12-03 16:33 ` Peter Maydell
2015-12-03 17:19 ` Alex Williamson
2015-12-03 17:36 ` Peter Maydell
2015-12-03 17:58 ` Alex Williamson
2015-12-07 10:53 ` Pavel Fedin [this message]
2015-12-07 11:20 ` Peter Maydell
2015-12-08 23:42 ` Alex Williamson
2015-12-09 8:08 ` Pavel Fedin
2015-12-09 10:09 ` Alex Bennée
2015-11-24 15:34 ` Peter Maydell
2015-11-25 7:00 ` Pavel Fedin
2015-12-02 19:05 ` Alex Williamson
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