[PATCH 20/25] KVM: X86: Introduce tdx_get_kvm_supported_cpuid()

Rick Edgecombe
2024-08-12T22:48:44Z

Two future TDX ioctl's will want to filter output by supported CPUID

Add a helper in TDX code instead of using
kvm_get_supported_cpuid_internal() directly for two reasons:
1. Logic around which CPUID leaf ranges to query would need to be
duplicated.
2. Future patches will add TDX specific fixups to the CPUID data provided
by kvm_get_supported_cpuid_internal().

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
uAPI breakout v1:
- New patch
---
arch/x86/kvm/vmx/tdx.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index ba7b436fae86..b2ed031ac0d6 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1014,6 +1014,30 @@ static int tdx_td_vcpu_init(struct kvm_vcpu *vcpu, u64 vcpu_rcx)
return ret;
}

+static int __maybe_unused tdx_get_kvm_supported_cpuid(struct kvm_cpuid2 **cpuid)
+{
+ int r;
+ static const u32 funcs[] = {
+ 0, 0x80000000, KVM_CPUID_SIGNATURE,
+ };
+
+ *cpuid = kzalloc(sizeof(struct kvm_cpuid2) +
+ sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES,
+ GFP_KERNEL);
+ if (!*cpuid)
+ return -ENOMEM;
+ (*cpuid)->nent = KVM_MAX_CPUID_ENTRIES;
+ r = kvm_get_supported_cpuid_internal(*cpuid, funcs, ARRAY_SIZE(funcs));
+ if (r)
+ goto err;
+
+ return 0;
+err:
+ kfree(*cpuid);
+ *cpuid = NULL;
+ return r;
+}
+
static int tdx_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)
{
struct msr_data apic_base_msr;
--
2.34.1