linux-kernel - [PATCH 5.11 301/329] KVM: VMX: Do not advertise RDPID if ENABLE

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Date:   Mon, 17 May 2021 16:03:32 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sean Christopherson <seanjc@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Reiji Watanabe <reijiw@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.11 301/329] KVM: VMX: Do not advertise RDPID if ENABLE_RDTSCP control is unsupported

From: Sean Christopherson <seanjc@...gle.com>

commit 8aec21c04caa2000f91cf8822ae0811e4b0c3971 upstream.

Clear KVM's RDPID capability if the ENABLE_RDTSCP secondary exec control is
unsupported.  Despite being enumerated in a separate CPUID flag, RDPID is
bundled under the same VMCS control as RDTSCP and will #UD in VMX non-root
if ENABLE_RDTSCP is not enabled.

Fixes: 41cd02c6f7f6 ("kvm: x86: Expose RDPID in KVM_GET_SUPPORTED_CPUID")
Cc: stable@...r.kernel.org
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Message-Id: <20210504171734.1434054-2-seanjc@...gle.com>
Reviewed-by: Jim Mattson <jmattson@...gle.com>
Reviewed-by: Reiji Watanabe <reijiw@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/vmx/vmx.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7288,9 +7288,11 @@ static __init void vmx_set_cpu_caps(void
 	if (!cpu_has_vmx_xsaves())
 		kvm_cpu_cap_clear(X86_FEATURE_XSAVES);
 
-	/* CPUID 0x80000001 */
-	if (!cpu_has_vmx_rdtscp())
+	/* CPUID 0x80000001 and 0x7 (RDPID) */
+	if (!cpu_has_vmx_rdtscp()) {
 		kvm_cpu_cap_clear(X86_FEATURE_RDTSCP);
+		kvm_cpu_cap_clear(X86_FEATURE_RDPID);
+	}
 
 	if (cpu_has_vmx_waitpkg())
 		kvm_cpu_cap_check_and_set(X86_FEATURE_WAITPKG);