[RFC PATCH 20/67] KVM: x86: Make KVM_CAP_X86_SMM a per-VM capability

From: isaku . yamahata
Date: Mon Nov 16 2020 - 13:28:16 EST


From: Isaku Yamahata <isaku.yamahata@xxxxxxxxxxxxxxx>

TDX doesn't support SMM, whereas VMX conditionally support SMM. Rework
kvm_x86_ops.has_emulated_msr() to take a struct kvm so that TDX can
reject SMM by way of the MSR_IA32_SMBASE check.

This pair with a QEMU change to query SMM support using a VM ioctl().

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxxxxxxxx>
Co-developed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/svm/svm.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/x86.c | 4 ++--
4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 70528102d865..00b34d8f038b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1092,7 +1092,7 @@ struct kvm_x86_ops {
void (*hardware_disable)(void);
void (*hardware_unsetup)(void);
bool (*cpu_has_accelerated_tpr)(void);
- bool (*has_emulated_msr)(u32 index);
+ bool (*has_emulated_msr)(struct kvm *kvm, u32 index);
void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu);

bool (*is_vm_type_supported)(unsigned long vm_type);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 11ab330a9b55..241a26e1fa71 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3720,7 +3720,7 @@ static bool svm_cpu_has_accelerated_tpr(void)
return false;
}

-static bool svm_has_emulated_msr(u32 index)
+static bool svm_has_emulated_msr(struct kvm *kvm, u32 index)
{
switch (index) {
case MSR_IA32_MCG_EXT_CTL:
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b3ecdb96789a..2ee7eb7dac26 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6405,7 +6405,7 @@ static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
handle_exception_nmi_irqoff(vmx);
}

-static bool vmx_has_emulated_msr(u32 index)
+static bool vmx_has_emulated_msr(struct kvm *kvm, u32 index)
{
switch (index) {
case MSR_IA32_SMBASE:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2fb0d20c5788..2f4b226d5b89 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3726,7 +3726,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
* fringe case that is not enabled except via specific settings
* of the module parameters.
*/
- r = kvm_x86_ops.has_emulated_msr(MSR_IA32_SMBASE);
+ r = kvm_x86_ops.has_emulated_msr(kvm, MSR_IA32_SMBASE);
break;
case KVM_CAP_VAPIC:
r = !kvm_x86_ops.cpu_has_accelerated_tpr();
@@ -5783,7 +5783,7 @@ static void kvm_init_msr_list(void)
}

for (i = 0; i < ARRAY_SIZE(emulated_msrs_all); i++) {
- if (!kvm_x86_ops.has_emulated_msr(emulated_msrs_all[i]))
+ if (!kvm_x86_ops.has_emulated_msr(NULL, emulated_msrs_all[i]))
continue;

emulated_msrs[num_emulated_msrs++] = emulated_msrs_all[i];
--
2.17.1