> From: Nadav Har'El
> Sent: Tuesday, May 17, 2011 3:53 AM
>
> Implement the VMLAUNCH and VMRESUME instructions, allowing a guest
> hypervisor to run its own guests.
>
> This patch does not include some of the necessary validity checks on
> vmcs12 fields before the entry. These will appear in a separate patch
> below.
>
> Signed-off-by: Nadav Har'El <nyh@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 84
> +++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 82 insertions(+), 2 deletions(-)
>
> --- .before/arch/x86/kvm/vmx.c 2011-05-16 22:36:49.000000000 +0300
> +++ .after/arch/x86/kvm/vmx.c 2011-05-16 22:36:49.000000000 +0300
> @@ -347,6 +347,9 @@ struct nested_vmx {
> /* vmcs02_list cache of VMCSs recently used to run L2 guests */
> struct list_head vmcs02_pool;
> int vmcs02_num;
> +
> + /* Saving the VMCS that we used for running L1 */
> + struct saved_vmcs saved_vmcs01;
> u64 vmcs01_tsc_offset;
> /*
> * Guest pages referred to in vmcs02 with host-physical pointers, so
> @@ -4668,6 +4671,8 @@ static void nested_free_all_saved_vmcss(
> kfree(item);
> }
> vmx->nested.vmcs02_num = 0;
> + if (is_guest_mode(&vmx->vcpu))
> + nested_free_saved_vmcs(vmx, &vmx->nested.saved_vmcs01);
> }
>
> /* Get a vmcs02 for the current vmcs12. */
> @@ -4959,6 +4964,21 @@ static int handle_vmclear(struct kvm_vcp
> return 1;
> }
>
> +static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch);
> +
> +/* Emulate the VMLAUNCH instruction */
> +static int handle_vmlaunch(struct kvm_vcpu *vcpu)
> +{
> + return nested_vmx_run(vcpu, true);
> +}
> +
> +/* Emulate the VMRESUME instruction */
> +static int handle_vmresume(struct kvm_vcpu *vcpu)
> +{
> +
> + return nested_vmx_run(vcpu, false);
> +}
> +
> enum vmcs_field_type {
> VMCS_FIELD_TYPE_U16 = 0,
> VMCS_FIELD_TYPE_U64 = 1,
> @@ -5239,11 +5259,11 @@ static int (*kvm_vmx_exit_handlers[])(st
> [EXIT_REASON_INVLPG] = handle_invlpg,
> [EXIT_REASON_VMCALL] = handle_vmcall,
> [EXIT_REASON_VMCLEAR] = handle_vmclear,
> - [EXIT_REASON_VMLAUNCH] = handle_vmx_insn,
> + [EXIT_REASON_VMLAUNCH] = handle_vmlaunch,
> [EXIT_REASON_VMPTRLD] = handle_vmptrld,
> [EXIT_REASON_VMPTRST] = handle_vmptrst,
> [EXIT_REASON_VMREAD] = handle_vmread,
> - [EXIT_REASON_VMRESUME] = handle_vmx_insn,
> + [EXIT_REASON_VMRESUME] = handle_vmresume,
> [EXIT_REASON_VMWRITE] = handle_vmwrite,
> [EXIT_REASON_VMOFF] = handle_vmoff,
> [EXIT_REASON_VMON] = handle_vmon,
> @@ -6129,6 +6149,66 @@ static void nested_maintain_per_cpu_list
> }
> }
>
> +/*
> + * nested_vmx_run() handles a nested entry, i.e., a VMLAUNCH or
> VMRESUME on L1
> + * for running an L2 nested guest.
> + */
> +static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
> +{
> + struct vmcs12 *vmcs12;
> + struct vcpu_vmx *vmx = to_vmx(vcpu);
> + int cpu;
> + struct saved_vmcs *saved_vmcs02;
> +
> + if (!nested_vmx_check_permission(vcpu))
> + return 1;
> + skip_emulated_instruction(vcpu);
> +
> + vmcs12 = get_vmcs12(vcpu);
> +
> + enter_guest_mode(vcpu);
> +
> + vmx->nested.vmcs01_tsc_offset = vmcs_read64(TSC_OFFSET);
> +
> + /*
> + * Switch from L1's VMCS (vmcs01), to L2's VMCS (vmcs02). Remember
> + * vmcs01, on which CPU it was last loaded, and whether it was launched
> + * (we need all these values next time we will use L1). Then recall
> + * these values from the last time vmcs02 was used.
> + */
> + saved_vmcs02 = nested_get_current_vmcs02(vmx);
> + if (!saved_vmcs02)
> + return -ENOMEM;
> +
> + cpu = get_cpu();
> + vmx->nested.saved_vmcs01.vmcs = vmx->vmcs;
> + vmx->nested.saved_vmcs01.cpu = vcpu->cpu;
> + vmx->nested.saved_vmcs01.launched = vmx->launched;
> + vmx->vmcs = saved_vmcs02->vmcs;
> + vcpu->cpu = saved_vmcs02->cpu;
this may be another valid reason for your check on cpu_online in your
latest [08/31] local_vcpus_link fix, since cpu may be offlined after
this assignment. :-)
> + vmx->launched = saved_vmcs02->launched;
> +
> + nested_maintain_per_cpu_lists(vmx,
> + saved_vmcs02, &vmx->nested.saved_vmcs01);
> +
> + vmx_vcpu_put(vcpu);
> + vmx_vcpu_load(vcpu, cpu);
> + vcpu->cpu = cpu;
> + put_cpu();
> +
> + vmcs12->launch_state = 1;
> +
> + prepare_vmcs02(vcpu, vmcs12);
Since prepare_vmcs may fail, add a check here and move launch_state
assignment after its success?
Thanks
Kevin
> +
> + /*
> + * Note no nested_vmx_succeed or nested_vmx_fail here. At this point
> + * we are no longer running L1, and VMLAUNCH/VMRESUME has not yet
> + * returned as far as L1 is concerned. It will only return (and set
> + * the success flag) when L2 exits (see nested_vmx_vmexit()).
> + */
> + return 1;
> +}
> +
> static int vmx_check_intercept(struct kvm_vcpu *vcpu,
> struct x86_instruction_info *info,
> enum x86_intercept_stage stage)
> --
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