linux-kernel - [PATCH 1/2] kvm/x86/vmx: enable X86_FEATURE

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Message-Id: <20200523161455.3940-2-mlevitsk@redhat.com>
Date:   Sat, 23 May 2020 19:14:54 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, Tao Xu <tao3.xu@...el.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-kernel@...r.kernel.org, Joerg Roedel <joro@...tes.org>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        Wanpeng Li <wanpengli@...cent.com>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jingqi Liu <jingqi.liu@...el.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 1/2] kvm/x86/vmx: enable X86_FEATURE_WAITPKG in KVM capabilities

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@...hat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.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