Re: [PATCH v2] KVM: nVMX: expose VPID capability to L1

From: Wanpeng Li
Date: Tue Sep 29 2015 - 07:05:26 EST


On 9/29/15 6:39 PM, Paolo Bonzini wrote:
On 29/09/2015 04:55, Wanpeng Li wrote:
Expose VPID capability to L1.

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
---
v1 -> v2:
* set only VMX_VPID_EXTENT_GLOBAL_CONTEXT_BIT
Thanks. I've checked more thoroughly your implementation against the
SDM now, and there are a few missing things between this patch and the
one that emulates INVVPID:

- you're not setting bit 32 of the VMX_EPT_VPID_CAP MSR

- you were not checking against the supported types in the
implementation of the INVVPID instruction

- the memory operand must always be read even if it isn't needed (e.g.,
for type==global), similar to INVEPT

- for single-context invalidation you're not checking that VPID != 0,
though in practice that doesn't matter because we don't want to support
single-context invalidation

- you're always setting the MSR's bits to 1 even if !enable_vpid

At this point it's better if you resend the whole nested VPID
implementation, i.e. the following five patches:

KVM: VMX: adjust interface to allocate/free_vpid
KVM: VMX: introduce __vmx_flush_tlb to handle specific vpid
KVM: nVMX: emulate the INVVPID instruction
KVM: nVMX: nested VPID emulation
KVM: nVMX: expose VPID capability to L1

with the above issues fixed. Please also send kvm-unit-tests patches
that tests for the error cases.

Ok, I will do this after the vacation(until 10.7) in my country. :-)

Regards,
Wanpeng Li
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