[PATCH 1/2] kvm/x86/vmx: enable X86_FEATURE_WAITPKG in KVM capabilities

From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Tao Xu <tao3.xu@intel.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Jim Mattson <jmattson@google.com>,
	linux-kernel@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	Wanpeng Li <wanpengli@tencent.com>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Jingqi Liu <jingqi.liu@intel.com>,
	Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 1/2] kvm/x86/vmx: enable X86_FEATURE_WAITPKG in KVM capabilities
Date: Sat, 23 May 2020 19:14:54 +0300	[thread overview]
Message-ID: <20200523161455.3940-2-mlevitsk@redhat.com> (raw)
In-Reply-To: <20200523161455.3940-1-mlevitsk@redhat.com>

Even though we might not allow the guest to use
WAITPKG's new instructions, we should tell KVM
that the feature is supported by the host CPU.

Note that vmx_waitpkg_supported checks that WAITPKG
_can_ be set in secondary execution controls as specified
by VMX capability MSR, rather that we actually enable it for a guest.

Fixes: e69e72faa3a0 KVM: x86: Add support for user wait instructions

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/vmx/vmx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 55712dd86bafa..fca493d4517c5 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7298,6 +7298,9 @@ static __init void vmx_set_cpu_caps(void)
 	/* CPUID 0x80000001 */
 	if (!cpu_has_vmx_rdtscp())
 		kvm_cpu_cap_clear(X86_FEATURE_RDTSCP);
+
+	if (vmx_waitpkg_supported())
+		kvm_cpu_cap_check_and_set(X86_FEATURE_WAITPKG);
 }
 
 static void vmx_request_immediate_exit(struct kvm_vcpu *vcpu)
-- 
2.26.2

