Il 20/08/2014 22:53, Radim Krčmář ha scritto:
> Change PLE window into per-VCPU variable, seeded from module parameter,
> to allow greater flexibility.
>
> Brings in a small overhead on every vmentry.
>
> Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 2b306f9..18e0e52 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -484,6 +484,9 @@ struct vcpu_vmx {
>
> /* Support for a guest hypervisor (nested VMX) */
> struct nested_vmx nested;
> +
> + /* Dynamic PLE window. */
> + int ple_window;
> };
>
> enum segment_cache_field {
> @@ -4402,7 +4405,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
>
> if (ple_gap) {
> vmcs_write32(PLE_GAP, ple_gap);
> - vmcs_write32(PLE_WINDOW, ple_window);
> + vmx->ple_window = ple_window;
> }
>
> vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, 0);
> @@ -7387,6 +7390,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
> if (vmx->emulation_required)
> return;
>
> + if (ple_gap)
> + vmcs_write32(PLE_WINDOW, vmx->ple_window);
Maybe we can add a ple_window_dirty field? It can be tested instead of
ple_gap to avoid the vmwrite in the common case?
Paolo
> if (vmx->nested.sync_shadow_vmcs) {
> copy_vmcs12_to_shadow(vmx);
> vmx->nested.sync_shadow_vmcs = false;
>
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