linux-kernel - [PATCH v6 11/11] KVM: x86: Disable Intel Processor Trace when VMXON in L1 guest

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 linux-hardening linux-cve-announce 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]

Message-Id: <1521544918-31084-12-git-send-email-luwei.kang@intel.com>
Date:   Tue, 20 Mar 2018 19:21:58 +0800
From:   Luwei Kang <luwei.kang@...el.com>
To:     kvm@...r.kernel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, pbonzini@...hat.com, rkrcmar@...hat.com,
        linux-kernel@...r.kernel.org, joro@...tes.org,
        Luwei Kang <luwei.kang@...el.com>
Subject: [PATCH v6 11/11] KVM: x86: Disable Intel Processor Trace when VMXON in L1 guest

Currently, Intel Processor Trace do not support tracing in L1 guest
VMX operation(IA32_VMX_MISC[bit 14] is 0). As mentioned in SDM,
on these type of processors, execution of the VMXON instruction will
clears IA32_RTIT_CTL.TraceEn and any attempt to write IA32_RTIT_CTL
causes a general-protection exception (#GP).

Signed-off-by: Luwei Kang <luwei.kang@...el.com>
---
 arch/x86/kvm/vmx.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 27185da..77a28f3 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3763,7 +3763,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	case MSR_IA32_RTIT_CTL:
 		if ((pt_mode != PT_MODE_HOST_GUEST) ||
-			vmx_rtit_ctl_check(vcpu, data))
+			vmx_rtit_ctl_check(vcpu, data) ||
+			vmx->nested.vmxon)
 			return 1;
 		vmcs_write64(GUEST_IA32_RTIT_CTL, data);
 		pt_set_intercept_for_msr(vmx, !(data & RTIT_CTL_TRACEEN));
@@ -7869,6 +7870,12 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
 	if (ret)
 		return ret;
 
+	if (pt_mode == PT_MODE_HOST_GUEST) {
+		vmx->pt_desc.guest.ctl = 0;
+		vmcs_write64(GUEST_IA32_RTIT_CTL, 0);
+		pt_set_intercept_for_msr(vmx, 1);
+	}
+
 	nested_vmx_succeed(vcpu);
 	return kvm_skip_emulated_instruction(vcpu);
 }
-- 
1.8.3.1