Hi Gleb,
On 07/03/2014 02:04 PM, Gleb Natapov wrote:
On Thu, Jul 03, 2014 at 09:17:59AM +0800, Tang Chen wrote:
Hi Gleb,
On 07/02/2014 05:00 PM, Tang Chen wrote:
Hi Gleb, Marcelo,
Please help to review this patch-set.
NOTE: This patch-set doesn't work properly.
ept identity pagetable and apic access page in kvm are pinned in memory.
As a result, they cannot be migrated/hot-removed.
But actually they don't need to be pinned in memory.
This patch-set introduces two new vcpu requests: KVM_REQ_MIGRATE_EPT and KVM_REQ_MIGRATE_APIC.
These two requests are made when the two pages are migrated by the mmu_notifier
to reset the related variable to unusable value. And will also be made when
ept violation happens to reset new pages.
[Known problem]
After this patch-set applied, the two pages can be migrated/hot-removed.
But after migrating apic access page, the guest died.
The host physical address of apic access page is stored in VMCS. I reset
it to 0 to stop guest from accessing it when it is unmapped by
kvm_mmu_notifier_invalidate_page(). And reset it to new page's host physical
address in tdp_page_fault(). But it seems that guest will access apic page
directly by the host physical address.
Would you please to give some advice about this problem ?
I haven't reviewed third patch yet, will do ASAP.
I printed some info in the kernel, and I found that mmu_notifier
unmapped the
apic page and set VMCS APIC_ACCESS_ADDR to 0. But apic page ept
violation didn't
happen. And the guest stopped running.
I think when guest tried to access apic page, there was no ept violation
happened.
And as a result, VMCS APIC_ACCESS_ADDR was not correctly set.
Referring to Intel Software Developer's Manuel Vol 3B, when accessing
apic page
using translation with a large page (2M, 4M, 1G), APIC VM_exit will not
happen.
How do you think about this ?
Thanks. :)
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