On Fri, Oct 08 2021 at 22:37, Kuppuswamy Sathyanarayanan wrote:
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>So if TDX is not enabled in Kconfig this cannot be optimized out unless
#ifdef CONFIG_KVM_GUEST
@@ -32,6 +34,10 @@ static inline bool kvm_check_and_clear_guest_paused(void)
static inline long kvm_hypercall0(unsigned int nr)
{
long ret;
+
+ if (cc_platform_has(CC_ATTR_GUEST_TDX))
+ return tdx_kvm_hypercall(nr, 0, 0, 0, 0);
CC_PLATFORM is disabled as well. But what's worse is that every
hypercall needs to call into cc_platform_has().
None of the hypercalls is used before the early TDX detection. So we can
simply use
if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
here, right? Then you add X86_FEATURE_TDX_GUEST to the disabled feature
bits correctly and all of the above is solved.
Hmm?
+#if defined(CONFIG_KVM_GUEST) && defined(CONFIG_INTEL_TDX_GUEST)Can we make that a proper exported function (instead of
+static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1,
+ unsigned long p2, unsigned long p3,
+ unsigned long p4)
+{
+ struct tdx_hypercall_output out;
+ u64 err;
+
+ err = __tdx_hypercall(TDX_HYPERCALL_VENDOR_KVM, nr, p1, p2,
+ p3, p4, &out);
+
+ /*
+ * Non zero return value means buggy TDX module (which is fatal).
+ * So use BUG_ON() to panic.
+ */
+ BUG_ON(err);
+
+ return out.r10;
+}
tdx_kvm_hypercall) so we don't end up with the very same code inlined
all over the place?
--
Thanks,
tglx