On Wed, Apr 17, 2013 at 02:53:10PM +0300, Abel Gordon wrote:
> Allocate a shadow vmcs used by the processor to shadow part of the fields
> stored in the software defined VMCS12 (let L1 access fields without causing
> exits). Note we keep a shadow vmcs only for the current vmcs12. Once a vmcs12
> becomes non-current, its shadow vmcs is released.
>
>
> Signed-off-by: Abel Gordon <abelg@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> --- .before/arch/x86/kvm/vmx.c 2013-04-17 14:20:50.000000000 +0300
> +++ .after/arch/x86/kvm/vmx.c 2013-04-17 14:20:50.000000000 +0300
> @@ -355,6 +355,7 @@ struct nested_vmx {
> /* The host-usable pointer to the above */
> struct page *current_vmcs12_page;
> struct vmcs12 *current_vmcs12;
> + struct vmcs *current_shadow_vmcs;
>
> /* vmcs02_list cache of VMCSs recently used to run L2 guests */
> struct list_head vmcs02_pool;
> @@ -5980,6 +5981,7 @@ static int handle_vmptrld(struct kvm_vcp
> gva_t gva;
> gpa_t vmptr;
> struct x86_exception e;
> + struct vmcs *shadow_vmcs;
>
> if (!nested_vmx_check_permission(vcpu))
> return 1;
> @@ -6026,6 +6028,19 @@ static int handle_vmptrld(struct kvm_vcp
> vmx->nested.current_vmptr = vmptr;
> vmx->nested.current_vmcs12 = new_vmcs12;
> vmx->nested.current_vmcs12_page = page;
> + if (enable_shadow_vmcs) {
> + shadow_vmcs = alloc_vmcs();
Next patch frees vmx->nested.current_shadow_vmcs couple of lines above.
What about reusing previous page instead of allocation new one each
time?
> + if (!shadow_vmcs) {
> + nested_vmx_failInvalid(vcpu);
> + skip_emulated_instruction(vcpu);
> + return 1;
> + }
> + /* mark vmcs as shadow */
> + shadow_vmcs->revision_id |= (1u << 31);
> + /* init shadow vmcs */
> + vmcs_clear(shadow_vmcs);
> + vmx->nested.current_shadow_vmcs = shadow_vmcs;
> + }
> }
>
> nested_vmx_succeed(vcpu);
>
> --
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--
Gleb.
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