On 7/7/14, 2:54 PM, Gleb Natapov wrote:
On Mon, Jul 07, 2014 at 02:42:27PM +0300, Nadav Amit wrote:
Tang,
Running some (unrelated) tests I see that KVM does not handle APIC base
relocation correctly. When the base is changed, kvm_lapic_set_base just
changes lapic->base_address without taking further action (i.e., modifying
the VMCS apic address in VMX).
This patch follows KVM bad behavior by using the constant
VMX_APIC_ACCESS_PAGE_ADDR instead of lapic->base_address.
There is no OS out there that relocates APIC base (in fact it was not always
relocatable on real HW), so there is not point in complicating the code to support
it. In fact current APIC_ACCESS_ADDR handling relies on the fact that all vcpus
has apic mapped at the same address.
Anyhow, I didn't see anything that would make my life (in fixing the lapic
base issue) too difficult. Yet, feel free in making it more "fix-friendly".
Why would you want to fix it?
If there is no general need, I will not send a fix. However, I think the
very least a warning message should be appear if the guest relocates the
APIC base.
Nadav
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