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Date: Tue, 29 Nov 2016 18:14:06 -0800
From: David Matlack <dmatlack@...gle.com>
To: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, jmattson@...gle.com,
rkrcmar@...hat.com, pbonzini@...hat.com,
David Matlack <dmatlack@...gle.com>
Subject: [PATCH v3 1/5] KVM: nVMX: generate non-true VMX MSRs based on true versions
The "non-true" VMX capability MSRs can be generated from their "true"
counterparts, by OR-ing the default1 bits. The default1 bits are fixed
and defined in the SDM.
Since we can generate the non-true VMX MSRs from the true versions,
there's no need to store both in struct nested_vmx. This also lets
userspace avoid having to restore the non-true MSRs.
Note this does not preclude emulating MSR_IA32_VMX_BASIC[55]=0. To do so,
we simply need to set all the default1 bits in the true MSRs (such that
the true MSRs and the generated non-true MSRs are equal).
Signed-off-by: David Matlack <dmatlack@...gle.com>
Suggested-by: Paolo Bonzini <pbonzini@...hat.com>
---
arch/x86/kvm/vmx.c | 45 +++++++++++++++++++--------------------------
1 file changed, 19 insertions(+), 26 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5382b82..0beb56a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -446,19 +446,21 @@ struct nested_vmx {
u16 vpid02;
u16 last_vpid;
+ /*
+ * We only store the "true" versions of the VMX capability MSRs. We
+ * generate the "non-true" versions by setting the must-be-1 bits
+ * according to the SDM.
+ */
u32 nested_vmx_procbased_ctls_low;
u32 nested_vmx_procbased_ctls_high;
- u32 nested_vmx_true_procbased_ctls_low;
u32 nested_vmx_secondary_ctls_low;
u32 nested_vmx_secondary_ctls_high;
u32 nested_vmx_pinbased_ctls_low;
u32 nested_vmx_pinbased_ctls_high;
u32 nested_vmx_exit_ctls_low;
u32 nested_vmx_exit_ctls_high;
- u32 nested_vmx_true_exit_ctls_low;
u32 nested_vmx_entry_ctls_low;
u32 nested_vmx_entry_ctls_high;
- u32 nested_vmx_true_entry_ctls_low;
u32 nested_vmx_misc_low;
u32 nested_vmx_misc_high;
u32 nested_vmx_ept_caps;
@@ -2712,9 +2714,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
vmx->nested.nested_vmx_exit_ctls_high |= VM_EXIT_CLEAR_BNDCFGS;
/* We support free control of debug control saving. */
- vmx->nested.nested_vmx_true_exit_ctls_low =
- vmx->nested.nested_vmx_exit_ctls_low &
- ~VM_EXIT_SAVE_DEBUG_CONTROLS;
+ vmx->nested.nested_vmx_exit_ctls_low &= ~VM_EXIT_SAVE_DEBUG_CONTROLS;
/* entry controls */
rdmsr(MSR_IA32_VMX_ENTRY_CTLS,
@@ -2733,9 +2733,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
vmx->nested.nested_vmx_entry_ctls_high |= VM_ENTRY_LOAD_BNDCFGS;
/* We support free control of debug control loading. */
- vmx->nested.nested_vmx_true_entry_ctls_low =
- vmx->nested.nested_vmx_entry_ctls_low &
- ~VM_ENTRY_LOAD_DEBUG_CONTROLS;
+ vmx->nested.nested_vmx_entry_ctls_low &= ~VM_ENTRY_LOAD_DEBUG_CONTROLS;
/* cpu-based controls */
rdmsr(MSR_IA32_VMX_PROCBASED_CTLS,
@@ -2768,8 +2766,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
CPU_BASED_USE_MSR_BITMAPS;
/* We support free control of CR3 access interception. */
- vmx->nested.nested_vmx_true_procbased_ctls_low =
- vmx->nested.nested_vmx_procbased_ctls_low &
+ vmx->nested.nested_vmx_procbased_ctls_low &=
~(CPU_BASED_CR3_LOAD_EXITING | CPU_BASED_CR3_STORE_EXITING);
/* secondary cpu-based controls */
@@ -2868,36 +2865,32 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
*pdata = vmx_control_msr(
vmx->nested.nested_vmx_pinbased_ctls_low,
vmx->nested.nested_vmx_pinbased_ctls_high);
+ if (msr_index == MSR_IA32_VMX_PINBASED_CTLS)
+ *pdata |= PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR;
break;
case MSR_IA32_VMX_TRUE_PROCBASED_CTLS:
- *pdata = vmx_control_msr(
- vmx->nested.nested_vmx_true_procbased_ctls_low,
- vmx->nested.nested_vmx_procbased_ctls_high);
- break;
case MSR_IA32_VMX_PROCBASED_CTLS:
*pdata = vmx_control_msr(
vmx->nested.nested_vmx_procbased_ctls_low,
vmx->nested.nested_vmx_procbased_ctls_high);
+ if (msr_index == MSR_IA32_VMX_PROCBASED_CTLS)
+ *pdata |= CPU_BASED_ALWAYSON_WITHOUT_TRUE_MSR;
break;
case MSR_IA32_VMX_TRUE_EXIT_CTLS:
- *pdata = vmx_control_msr(
- vmx->nested.nested_vmx_true_exit_ctls_low,
- vmx->nested.nested_vmx_exit_ctls_high);
- break;
case MSR_IA32_VMX_EXIT_CTLS:
*pdata = vmx_control_msr(
vmx->nested.nested_vmx_exit_ctls_low,
vmx->nested.nested_vmx_exit_ctls_high);
+ if (msr_index == MSR_IA32_VMX_EXIT_CTLS)
+ *pdata |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR;
break;
case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
- *pdata = vmx_control_msr(
- vmx->nested.nested_vmx_true_entry_ctls_low,
- vmx->nested.nested_vmx_entry_ctls_high);
- break;
case MSR_IA32_VMX_ENTRY_CTLS:
*pdata = vmx_control_msr(
vmx->nested.nested_vmx_entry_ctls_low,
vmx->nested.nested_vmx_entry_ctls_high);
+ if (msr_index == MSR_IA32_VMX_ENTRY_CTLS)
+ *pdata |= VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR;
break;
case MSR_IA32_VMX_MISC:
*pdata = vmx_control_msr(
@@ -10184,7 +10177,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
}
if (!vmx_control_verify(vmcs12->cpu_based_vm_exec_control,
- vmx->nested.nested_vmx_true_procbased_ctls_low,
+ vmx->nested.nested_vmx_procbased_ctls_low,
vmx->nested.nested_vmx_procbased_ctls_high) ||
!vmx_control_verify(vmcs12->secondary_vm_exec_control,
vmx->nested.nested_vmx_secondary_ctls_low,
@@ -10193,10 +10186,10 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
vmx->nested.nested_vmx_pinbased_ctls_low,
vmx->nested.nested_vmx_pinbased_ctls_high) ||
!vmx_control_verify(vmcs12->vm_exit_controls,
- vmx->nested.nested_vmx_true_exit_ctls_low,
+ vmx->nested.nested_vmx_exit_ctls_low,
vmx->nested.nested_vmx_exit_ctls_high) ||
!vmx_control_verify(vmcs12->vm_entry_controls,
- vmx->nested.nested_vmx_true_entry_ctls_low,
+ vmx->nested.nested_vmx_entry_ctls_low,
vmx->nested.nested_vmx_entry_ctls_high))
{
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
--
2.8.0.rc3.226.g39d4020
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