* question about nested ntp
@ 2010-10-12 13:26 Gleb Natapov
2010-10-13 8:57 ` Roedel, Joerg
0 siblings, 1 reply; 3+ messages in thread
From: Gleb Natapov @ 2010-10-12 13:26 UTC (permalink / raw)
To: joerg.roedel; +Cc: kvm
Hi Joerg,
I have a question about nested ntp code. Comment in init_kvm_nested_mmu()
function says "arch.mmu.gva_to_gpa translates l2_gva to l1_gpa". If
I read the code correctly at the time of nested guest execution
arch.mmu.gva_to_gpa() points to one of paging*_gva_to_gpa() variants. The
function calls walk_addr() with provided address which should be
l2_gva according to the comment. Now when NPF happens while nested
guest runs arch.mmu.page_fault() is called which translates to call
to one of paging*_page_fault() variants. paging*_page_fault() calls
walk_addr() too, but now it gets l2_gpa as a parameter since during
NPF svm->vmcb->control.exit_info_2 will not point to l2_gva, but l2_gpa
instead. Do I miss something here?
--
Gleb.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: question about nested ntp
2010-10-12 13:26 question about nested ntp Gleb Natapov
@ 2010-10-13 8:57 ` Roedel, Joerg
2010-10-13 9:59 ` Gleb Natapov
0 siblings, 1 reply; 3+ messages in thread
From: Roedel, Joerg @ 2010-10-13 8:57 UTC (permalink / raw)
To: Gleb Natapov; +Cc: kvm@vger.kernel.org
Hi Gleb,
On Tue, Oct 12, 2010 at 09:26:11AM -0400, Gleb Natapov wrote:
> I have a question about nested ntp code. Comment in init_kvm_nested_mmu()
> function says "arch.mmu.gva_to_gpa translates l2_gva to l1_gpa". If
> I read the code correctly at the time of nested guest execution
> arch.mmu.gva_to_gpa() points to one of paging*_gva_to_gpa() variants. The
> function calls walk_addr() with provided address which should be
> l2_gva according to the comment. Now when NPF happens while nested
> guest runs arch.mmu.page_fault() is called which translates to call
> to one of paging*_page_fault() variants. paging*_page_fault() calls
> walk_addr() too, but now it gets l2_gpa as a parameter since during
> NPF svm->vmcb->control.exit_info_2 will not point to l2_gva, but l2_gpa
> instead. Do I miss something here?
No, the comment is wrong. The comment actually was right in -v1 of the
patch-series. But I changed that in -v2 and forgot the update/remove the
comment. Thanks for mentioning that :-)
Joerg
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: question about nested ntp
2010-10-13 8:57 ` Roedel, Joerg
@ 2010-10-13 9:59 ` Gleb Natapov
0 siblings, 0 replies; 3+ messages in thread
From: Gleb Natapov @ 2010-10-13 9:59 UTC (permalink / raw)
To: Roedel, Joerg; +Cc: kvm@vger.kernel.org
On Wed, Oct 13, 2010 at 10:57:55AM +0200, Roedel, Joerg wrote:
> Hi Gleb,
>
> On Tue, Oct 12, 2010 at 09:26:11AM -0400, Gleb Natapov wrote:
> > I have a question about nested ntp code. Comment in init_kvm_nested_mmu()
> > function says "arch.mmu.gva_to_gpa translates l2_gva to l1_gpa". If
> > I read the code correctly at the time of nested guest execution
> > arch.mmu.gva_to_gpa() points to one of paging*_gva_to_gpa() variants. The
> > function calls walk_addr() with provided address which should be
> > l2_gva according to the comment. Now when NPF happens while nested
> > guest runs arch.mmu.page_fault() is called which translates to call
> > to one of paging*_page_fault() variants. paging*_page_fault() calls
> > walk_addr() too, but now it gets l2_gpa as a parameter since during
> > NPF svm->vmcb->control.exit_info_2 will not point to l2_gva, but l2_gpa
> > instead. Do I miss something here?
>
> No, the comment is wrong. The comment actually was right in -v1 of the
> patch-series. But I changed that in -v2 and forgot the update/remove the
> comment. Thanks for mentioning that :-)
>
Ah, good. I thought I am going crazy.
--
Gleb.
^ permalink raw reply [flat|nested] 3+ messages in thread
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