[PATCH 4/9] KVM: VMX: introduce alloc_loaded_vmcs

[David Woodhouse]

From: Paolo Bonzini <pbonz...@redhat.com>

Group together the calls to alloc_vmcs and loaded_vmcs_init.  Soon we'll also
allocate an MSR bitmap there.

Cc: sta...@vger.kernel.org       # prereq for Spectre mitigation
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
(cherry picked from commit f21f165ef922c2146cc5bdc620f542953c41714b)
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
 arch/x86/kvm/vmx.c | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 55b1474..8c562da 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3522,11 +3522,6 @@ static struct vmcs *alloc_vmcs_cpu(int cpu)
        return vmcs;
 }
 
-static struct vmcs *alloc_vmcs(void)
-{
-       return alloc_vmcs_cpu(raw_smp_processor_id());
-}
-
 static void free_vmcs(struct vmcs *vmcs)
 {
        free_pages((unsigned long)vmcs, vmcs_config.order);
@@ -3545,6 +3540,22 @@ static void free_loaded_vmcs(struct loaded_vmcs 
*loaded_vmcs)
        WARN_ON(loaded_vmcs->shadow_vmcs != NULL);
 }
 
+static struct vmcs *alloc_vmcs(void)
+{
+       return alloc_vmcs_cpu(raw_smp_processor_id());
+}
+
+static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
+{
+       loaded_vmcs->vmcs = alloc_vmcs();
+       if (!loaded_vmcs->vmcs)
+               return -ENOMEM;
+
+       loaded_vmcs->shadow_vmcs = NULL;
+       loaded_vmcs_init(loaded_vmcs);
+       return 0;
+}
+
 static void free_kvm_area(void)
 {
        int cpu;
@@ -6947,6 +6958,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
        struct vmcs *shadow_vmcs;
        const u64 VMXON_NEEDED_FEATURES = FEATURE_CONTROL_LOCKED
                | FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
+       int r;
 
        /* The Intel VMX Instruction Reference lists a bunch of bits that
         * are prerequisite to running VMXON, most notably cr4.VMXE must be
@@ -6986,11 +6998,9 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
                return 1;
        }
 
-       vmx->nested.vmcs02.vmcs = alloc_vmcs();
-       vmx->nested.vmcs02.shadow_vmcs = NULL;
-       if (!vmx->nested.vmcs02.vmcs)
+       r = alloc_loaded_vmcs(&vmx->nested.vmcs02);
+       if (r < 0)
                goto out_vmcs02;
-       loaded_vmcs_init(&vmx->nested.vmcs02);
 
        if (cpu_has_vmx_msr_bitmap()) {
                vmx->nested.msr_bitmap =
@@ -9111,17 +9121,15 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm 
*kvm, unsigned int id)
        if (!vmx->guest_msrs)
                goto free_pml;
 
-       vmx->loaded_vmcs = &vmx->vmcs01;
-       vmx->loaded_vmcs->vmcs = alloc_vmcs();
-       vmx->loaded_vmcs->shadow_vmcs = NULL;
-       if (!vmx->loaded_vmcs->vmcs)
-               goto free_msrs;
        if (!vmm_exclusive)
                kvm_cpu_vmxon(__pa(per_cpu(vmxarea, raw_smp_processor_id())));
-       loaded_vmcs_init(vmx->loaded_vmcs);
+       err = alloc_loaded_vmcs(&vmx->vmcs01);
        if (!vmm_exclusive)
                kvm_cpu_vmxoff();
+       if (err < 0)
+               goto free_msrs;
 
+       vmx->loaded_vmcs = &vmx->vmcs01;
        cpu = get_cpu();
        vmx_vcpu_load(&vmx->vcpu, cpu);
        vmx->vcpu.cpu = cpu;
-- 
2.7.4