linux-kernel - Re: [PATCH 0/4] VMX Capability MSRs

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Date:   Wed, 23 Nov 2016 12:45:15 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     David Matlack <dmatlack@...gle.com>, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jmattson@...gle.com,
        rkrcmar@...hat.com
Subject: Re: [PATCH 0/4] VMX Capability MSRs



On 23/11/2016 02:14, David Matlack wrote:
> This patchset includes v2 of "KVM: nVMX: support restore of VMX capability
> MSRs" (patch 1) as well as some additional related patches that came up
> while preparing v2.
> 
> Patches 2 and 3 make KVM's emulation of MSR_IA32_VMX_CR{0,4}_FIXED1 more
> accurate. Patch 4 fixes a bug in emulated VM-entry that came up when
> testing patches 2 and 3.
> 
> Changes since v1:
>   * Support restoring less-capable versions of MSR_IA32_VMX_BASIC,
>     MSR_IA32_VMX_CR{0,4}_FIXED{0,1}.
>   * Include VMX_INS_OUTS in MSR_IA32_VMX_BASIC initial value.
> 
> David Matlack (4):
>   KVM: nVMX: support restore of VMX capability MSRs
>   KVM: nVMX: fix checks on CR{0,4} during virtual VMX operation
>   KVM: nVMX: accurate emulation of MSR_IA32_CR{0,4}_FIXED1
>   KVM: nVMX: load GUEST_EFER after GUEST_CR0 during emulated VM-entry
> 
>  arch/x86/include/asm/vmx.h |  31 ++++
>  arch/x86/kvm/vmx.c         | 443 +++++++++++++++++++++++++++++++++++++++------
>  2 files changed, 421 insertions(+), 53 deletions(-)
> 

The main question is whether patches 2-3 actually make
vmx_restore_fixed0/1_msr unnecessary, otherwise looks great.

It would be nice to have a testcase for patch 4, since it could go in
independently.

Paolo