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;
+ 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);
+
+ /*
+ * 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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