On 05/07/2017 18:48, Janakarajan Natarajan wrote:
> Enable the Virtual VMLOAD VMSAVE feature. This is done by setting bit 1
> at position B8h in the vmcb.
>
> The processor must have nested paging enabled, be in 64-bit mode and
> have support for the Virtual VMLOAD VMSAVE feature for the bit to be set
> in the vmcb.
>
> Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@xxxxxxx>
> ---
> arch/x86/include/asm/svm.h | 1 +
> arch/x86/kvm/svm.c | 21 +++++++++++++++++++++
> 2 files changed, 22 insertions(+)
>
> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
> index 74d1393..58fffe7 100644
> --- a/arch/x86/include/asm/svm.h
> +++ b/arch/x86/include/asm/svm.h
> @@ -120,6 +120,7 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
> #define AVIC_ENABLE_MASK (1 << AVIC_ENABLE_SHIFT)
>
> #define LBR_CTL_ENABLE_MASK BIT_ULL(0)
> +#define VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK BIT_ULL(1)
>
> #define SVM_INTERRUPT_SHADOW_MASK 1
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index eadecee..ae73e7c 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -275,6 +275,9 @@ static int avic;
> module_param(avic, int, S_IRUGO);
> #endif
>
> +/* enable/disable Virtual VMLOAD VMSAVE */
> +static bool has_vls = false;
Please make this a module parameter. Initialize the variable to true...
> /* AVIC VM ID bit masks and lock */
> static DECLARE_BITMAP(avic_vm_id_bitmap, AVIC_VM_ID_NR);
> static DEFINE_SPINLOCK(avic_vm_id_lock);
> @@ -1079,6 +1082,14 @@ static __init int svm_hardware_setup(void)
> }
> }
>
> + if (npt_enabled) {
> + if (boot_cpu_has(X86_FEATURE_VIRTUAL_VMLOAD_VMSAVE) &&
> + IS_ENABLED(CONFIG_X86_64)) {
... and reset it here if !npt_enabled ||
!boot_cpu_has(X86_FEATURE_VIRTUAL_VMLOAD_VMSAVE) ||
!IS_ENABLED(CONFIG_X86_64).
Paolo
> + pr_info("Virtual VMLOAD VMSAVE supported\n");
> + has_vls = true;
> + }
> + }
> +
> return 0;
>
> err:
> @@ -1266,6 +1277,16 @@ static void init_vmcb(struct vcpu_svm *svm)
> if (avic)
> avic_init_vmcb(svm);
>
> + /*
> + * If hardware supports Virtual VMLOAD VMSAVE then enable it
> + * in VMCB and clear intercepts to avoid #VMEXIT.
> + */
> + if (has_vls) {
> + clr_intercept(svm, INTERCEPT_VMLOAD);
> + clr_intercept(svm, INTERCEPT_VMSAVE);
> + svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
> + }
> +
> mark_all_dirty(svm->vmcb);
>
> enable_gif(svm);
>
