linux-kernel - [PATCH 5/9] KVM: VMX: Move Intel PT shenanigans out of VMXON/VMXOFF flows

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Date:   Wed, 30 Dec 2020 16:26:58 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        "H. Peter Anvin" <hpa@...or.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "David P . Reed" <dpreed@...pplum.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Uros Bizjak <ubizjak@...il.com>
Subject: [PATCH 5/9] KVM: VMX: Move Intel PT shenanigans out of VMXON/VMXOFF flows

Move the Intel PT tracking outside of the VMXON/VMXOFF helpers so that
a future patch can drop KVM's kvm_cpu_vmxoff() in favor of the kernel's
cpu_vmxoff() without an associated PT functional change, and without
losing symmetry between the VMXON and VMXOFF flows.

Barring undocumented behavior, this should have no meaningful effects
as Intel PT behavior does not interact with CR4.VMXE.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/vmx/vmx.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 65b5f02b199f..131f390ade24 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2265,7 +2265,6 @@ static int kvm_cpu_vmxon(u64 vmxon_pointer)
 	u64 msr;
 
 	cr4_set_bits(X86_CR4_VMXE);
-	intel_pt_handle_vmx(1);
 
 	asm_volatile_goto("1: vmxon %[vmxon_pointer]\n\t"
 			  _ASM_EXTABLE(1b, %l[fault])
@@ -2276,7 +2275,6 @@ static int kvm_cpu_vmxon(u64 vmxon_pointer)
 fault:
 	WARN_ONCE(1, "VMXON faulted, MSR_IA32_FEAT_CTL (0x3a) = 0x%llx\n",
 		  rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr) ? 0xdeadbeef : msr);
-	intel_pt_handle_vmx(0);
 	cr4_clear_bits(X86_CR4_VMXE);
 
 	return -EFAULT;
@@ -2299,9 +2297,13 @@ static int hardware_enable(void)
 	    !hv_get_vp_assist_page(cpu))
 		return -EFAULT;
 
+	intel_pt_handle_vmx(1);
+
 	r = kvm_cpu_vmxon(phys_addr);
-	if (r)
+	if (r) {
+		intel_pt_handle_vmx(0);
 		return r;
+	}
 
 	if (enable_ept)
 		ept_sync_global();
@@ -2327,7 +2329,6 @@ static void kvm_cpu_vmxoff(void)
 {
 	asm volatile (__ex("vmxoff"));
 
-	intel_pt_handle_vmx(0);
 	cr4_clear_bits(X86_CR4_VMXE);
 }
 
@@ -2335,6 +2336,8 @@ static void hardware_disable(void)
 {
 	vmclear_local_loaded_vmcss();
 	kvm_cpu_vmxoff();
+
+	intel_pt_handle_vmx(0);
 }
 
 /*
-- 
2.29.2.729.g45daf8777d-goog