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Re: [Xen-devel] [PATCH] Fix >4G i386 PAE grant table interface

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Fix >4G i386 PAE grant table interface
From: Steven Rostedt <srostedt@xxxxxxxxxx>
Date: Fri, 03 Nov 2006 08:43:00 -0500
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Jan Beulich wrote:
Steven Rostedt <srostedt@xxxxxxxxxx> 02.11.06 17:53 >>>
It has been discovered that i386 boxes with more than 4G of RAM would randomly crash. It was traced to the interface of blktap using gnttab_set_map_op.

It would pass in the 64 bit pte entry, but the gnttab_set_map_op would only take a 32 bit (on i386) unsigned long as a parameter. So we lose the top 32bits.

Could you use maddr_t here rather than uint64_t? For non-PAE i386
Linux, especially when using CONFIG_REGPARM, adding a useless
argument slot seems wasteful...


Actually, it makes no difference to me. In fact uint64_t was my third incarnation, since I wasn't sure what the best would be. I started with unsigned long long, then switched to u64, and then noticed that since host_addr is uint64_t, that seemed the proper thing to use.

So a maddr_t would work too.

Do you want to do the patch, or would you like me to send another patch that would do this change?

-- Steve


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