Messages in this thread | | | Date | Mon, 18 Jan 2010 17:53:53 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH v3 04/12] Add "handle page fault" PV helper. |
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On 01/18/2010 12:50 AM, Gleb Natapov wrote: > On Mon, Jan 18, 2010 at 12:34:16AM -0800, H. Peter Anvin wrote: >> On 01/17/2010 06:44 AM, Gleb Natapov wrote: >>> On Thu, Jan 14, 2010 at 06:31:07PM +0100, Peter Zijlstra wrote: >>>> On Tue, 2010-01-05 at 16:12 +0200, Gleb Natapov wrote: >>>>> Allow paravirtualized guest to do special handling for some page faults. >>>>> >>>>> The patch adds one 'if' to do_page_fault() function. The call is patched >>>>> out when running on physical HW. I ran kernbech on the kernel with and >>>>> without that additional 'if' and result were rawly the same: >>>> >>>> So why not program a different handler address for the #PF/#GP faults >>>> and avoid the if all together? >>> I would gladly use fault vector reserved by x86 architecture, but I am >>> not sure Intel will be happy about it. >>> >> >> That's what it's there for... see Peter Z.'s response. >> > Do you mean I can use one of exception vectors reserved by Intel > (20-31)? What Peter Z says is that I can register my own handler for > #PF and avoid the 'if' in non PV case as far as I understand him. >
What I mean is that vector 14 is page faults -- that's what it is all about. Why on Earth do you need another vector?
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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