Re: [PATCH v4 0/6] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

From: tangchen
Date: Mon Sep 01 2014 - 01:13:28 EST


Hi Gleb,

Would you please help to review these patches ?

Thanks.

On 08/27/2014 06:17 PM, Tang Chen wrote:
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.

[For ept identity page]
Just do not pin it. When it is migrated, guest will be able to find the
new page in the next ept violation.

[For apic access page]
The hpa of apic access page is stored in VMCS APIC_ACCESS_ADDR pointer.
When apic access page is migrated, we update VMCS APIC_ACCESS_ADDR pointer
for each vcpu in addition.

NOTE: Tested with -cpu xxx,-x2apic option.
But since nested vm pins some other pages in memory, if user uses nested
vm, memory hot-remove will not work.

Change log v3 -> v4:
1. The original patch 6 is now patch 5. ( by Jan Kiszka <jan.kiszka@xxxxxx> )
2. The original patch 1 is now patch 6 since we should unpin apic access page
at the very last moment.


Tang Chen (6):
kvm: Use APIC_DEFAULT_PHYS_BASE macro as the apic access page address.
kvm: Remove ept_identity_pagetable from struct kvm_arch.
kvm: Make init_rmode_identity_map() return 0 on success.
kvm, mem-hotplug: Reload L1' apic access page on migration in
vcpu_enter_guest().
kvm, mem-hotplug: Reload L1's apic access page on migration when L2 is
running.
kvm, mem-hotplug: Do not pin apic access page in memory.

arch/x86/include/asm/kvm_host.h | 3 +-
arch/x86/kvm/svm.c | 15 +++++-
arch/x86/kvm/vmx.c | 103 +++++++++++++++++++++++++++-------------
arch/x86/kvm/x86.c | 22 +++++++--
include/linux/kvm_host.h | 3 ++
virt/kvm/kvm_main.c | 30 +++++++++++-
6 files changed, 135 insertions(+), 41 deletions(-)


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