[PATCH v2 3/3] KVM: x86: simplify kvm_mwait_in_guest()

From: "Radim Krčmář" <rkrcmar@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Alexander Graf" <agraf@suse.de>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Jan H. Schönherr" <jschoenh@amazon.de>,
	"KarimAllah Ahmed" <karahmed@amazon.de>,
	"Jim Mattson" <jmattson@google.com>
Subject: [PATCH v2 3/3] KVM: x86: simplify kvm_mwait_in_guest()
Date: Wed, 29 Nov 2017 22:23:43 +0100	[thread overview]
Message-ID: <20171129212343.23167-4-rkrcmar@redhat.com> (raw)
In-Reply-To: <20171129212343.23167-1-rkrcmar@redhat.com>

If Intel/AMD implements MWAIT, we expect that it works well and only
reject known bugs;  no reason to do it the other way around for minor
vendors.  (Not that they are relevant ATM.)

This allows further simplification of kvm_mwait_in_guest().
And use boot_cpu_has() instead of "cpu_has(&boot_cpu_data," while at it.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/kvm/x86.h | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index d15859ec5e92..c69f973111cb 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -265,18 +265,8 @@ static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
 
 static inline bool kvm_mwait_in_guest(void)
 {
-	if (!cpu_has(&boot_cpu_data, X86_FEATURE_MWAIT))
-		return false;
-
-	switch (boot_cpu_data.x86_vendor) {
-	case X86_VENDOR_AMD:
-		/* All AMD CPUs have a working MWAIT implementation */
-		return true;
-	case X86_VENDOR_INTEL:
-		return !boot_cpu_has_bug(X86_BUG_MONITOR);
-	default:
-		return false;
-	}
+	return boot_cpu_has(X86_FEATURE_MWAIT) &&
+		!boot_cpu_has_bug(X86_BUG_MONITOR);
 }
 
 #endif
-- 
2.14.2
