From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Egger, Christoph" <chegger@amazon.de>
Subject: Re: hap_invlpg() vs INVLPGA
Date: Mon, 1 Feb 2016 09:14:15 +0100
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To: Jan Beulich <JBeulich@suse.com>
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On 01/02/16 09:04, Jan Beulich wrote:
>>> This, otoh, reads as if you imply we intercept the L2's INVLPG.
>>> Yet the INVLPG intercept gets cleared when the domain uses
>>> NPT (and your original change also didn't alter any intercept
>>> settings). Hence I'm still lost how hap_invlpg() can be reached
>>> in that case other than via emulating INVLPG in the instruction
>>> emulator.
>>
>> svm_invlpg_intercept() and vmx_invlpg_intercept() call
>> paging_invlpg().  paging_invlpg() calls hap_invlpg()
>> as initialized in xen/arch/x86/mm/hap/hap.c
> 
> That's all fine, but according to my previous reply: How does
> execution reach svm_invlpg_intercept() when the INVLPG
> intercept gets disabled for domains using HAP (NPT)?

The intercept bitmask for L1 guest and L2 guest gets binary or'ed
when emulating the VMENTRY for the L1 guest.
That way you get also intercepts for the L1 hypervisor.

Christoph

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