From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
TDX has its own limitation on the maximum number of vcpus. Make it backend
specific and return TDX specific value for KVM_CAP_MAX_VCPUS.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/include/asm/kvm-x86-ops.h | 1 +
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx/main.c | 13 +++++++++++++
arch/x86/kvm/x86.c | 2 ++
4 files changed, 17 insertions(+)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 58fbaa05fc8c..6914f1d61803 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -21,6 +21,7 @@ KVM_X86_OP(hardware_unsetup)
KVM_X86_OP(has_emulated_msr)
KVM_X86_OP(vcpu_after_set_cpuid)
KVM_X86_OP(is_vm_type_supported)
+KVM_X86_OP_OPTIONAL(max_vcpus);
KVM_X86_OP(vm_init)
KVM_X86_OP_OPTIONAL(vm_destroy)
KVM_X86_OP_OPTIONAL_RET0(vcpu_precreate)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 58fc697095fd..1c761c9e1edb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1547,6 +1547,7 @@ struct kvm_x86_ops {
void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu);
bool (*is_vm_type_supported)(unsigned long vm_type);
+ int (*max_vcpus)(struct kvm *kvm);
unsigned int vm_size;
int (*vm_init)(struct kvm *kvm);
void (*vm_destroy)(struct kvm *kvm);
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index d90da9fd75bf..41c2e4a1b157 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -6,6 +6,7 @@
#include "nested.h"
#include "pmu.h"
#include "tdx.h"
+#include "tdx_arch.h"
static bool enable_tdx __ro_after_init;
module_param_named(tdx, enable_tdx, bool, 0444);
@@ -16,6 +17,17 @@ static bool vt_is_vm_type_supported(unsigned long type)
(enable_tdx && tdx_is_vm_type_supported(type));
}
+static int vt_max_vcpus(struct kvm *kvm)
+{
+ if (!kvm)
+ return KVM_MAX_VCPUS;
+
+ if (is_td(kvm))
+ return min3(kvm->max_vcpus, KVM_MAX_VCPUS, TDX_MAX_VCPUS);
+
+ return kvm->max_vcpus;
+}
+
static __init int vt_hardware_setup(void)
{
int ret;
@@ -68,6 +80,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.has_emulated_msr = vmx_has_emulated_msr,
.is_vm_type_supported = vt_is_vm_type_supported,
+ .max_vcpus = vt_max_vcpus,
.vm_size = sizeof(struct kvm_vmx),
.vm_init = vt_vm_init,
.vm_destroy = vmx_vm_destroy,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3e00fb7863a8..c54baa3973f2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4490,6 +4490,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
break;
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
+ if (kvm_x86_ops.max_vcpus)
+ r = static_call(kvm_x86_max_vcpus)(kvm);
break;
case KVM_CAP_MAX_VCPU_ID:
r = KVM_MAX_VCPU_IDS;
--
2.25.1
