[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] MULTI_mmu_update, HYPERVISOR_mmu_update and pte entry
- To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
- From: Christopher Benninger <chrisbenninger@xxxxxxxxx>
- Date: Wed, 18 May 2011 05:25:30 +0000
- Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
- Delivery-date: Tue, 17 May 2011 22:26:37 -0700
- Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=l3mYkpEP+1CCzJmiqS5eK0QluRdLeuFMiTurq477Rlk7YggaddZ8pZ8+51hxxrKQnv 1lmY4BwJbJ4m7TSkYYOifBwlem1O9eNrPH6qI7eFvYyYjHFfY3hhcH5Xvsg15JpwigxD WLvSHvHG++Z5NibJJe/La0xY6c1ZVMw1AXEqk=
- List-id: Xen developer discussion <xen-devel.lists.xensource.com>
Hi Jeremy,
I am definitely doing something weird, but on purpose. I am trying to determine which process specifically owns the pte in question. I have a domU module which I can ask for information, I just dont know how to get the ptr provided, into a useful context I can send it.
Chris Benninger
On Tue, May 17, 2011 at 10:29 PM, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
On 05/12/2011 03:41 PM, chrisbenninger wrote:
> Hi, I am working on being able to determine which process owns a PTE
> being changed during each MMU update in 64-bit paravirtualized mode. I
> have a couple questions here.
>
> 1. When a linux DomU wants to make an update to a PTE, it calls
> HYPERVISOR_mmu_update? In my case it appears to be calling
> MULTI_mmu_update mostly. Are these two functions the only primary ways
> a VM will ask for an MMU update?
There's also update_va_mapping and direct writes to the pte which are
trapped and emulated. However, I've got patches to drop the use of
update_va_mapping in pvops Linux, at least.
> 2. The mmu_update struct that comes along with a MMU update has a
> /unint64_t ptr/ which is a machine address to the PTE being changed.
> Is there any way to use this machine address and determine the pte_t
> or page from within a DomU?
From within domU? You could convert it back into a pseudo-phys address
and get the pfn, but its hard to connect a random pte page to a virtual
address or even connect it to an address space.
What are you trying to achieve? Most usermode pte updates will be to
the current process.
J
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
