lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 29 Nov 2017 22:23:43 +0100
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Borislav Petkov <bp@...en8.de>, Alexander Graf <agraf@...e.de>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Jan H. Schönherr <jschoenh@...zon.de>,
        KarimAllah Ahmed <karahmed@...zon.de>,
        Jim Mattson <jmattson@...gle.com>
Subject: [PATCH v2 3/3] KVM: x86: simplify kvm_mwait_in_guest()

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@...hat.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

Powered by blists - more mailing lists