FAILED: patch "[PATCH] KVM: x86: Emulate RDPID only if RDTSCP is supported" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 85d0011264da24be08ae907d7f29983a597ca9b1 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
Date: Tue, 4 May 2021 10:17:21 -0700
Subject: [PATCH] KVM: x86: Emulate RDPID only if RDTSCP is supported

Do not advertise emulation support for RDPID if RDTSCP is unsupported. RDPID emulation subtly relies on MSR_TSC_AUX to exist in hardware, as both vmx_get_msr() and svm_get_msr() will return an error if the MSR is unsupported, i.e. ctxt->ops->get_msr() will fail and the emulator will inject a #UD.

Note, RDPID emulation also relies on RDTSCP being enabled in the guest, but this is a KVM bug and will eventually be fixed.

Message-Id: <[email protected]>

index 19606a341888..c0e8c5e92189 100644
@@ -637,7 +637,8 @@ static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
 	case 7:
 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 		entry->eax = 0;
-		entry->ecx = F(RDPID);
+		if (kvm_cpu_cap_has(X86_FEATURE_RDTSCP))
+			entry->ecx = F(RDPID);
 		++array->nent;
 	default:
 		break;