linux-kernel - [PATCH 4.19 001/101] kvm: nVMX: NMI-window and interrupt-window exiting should wake L2 from HLT

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Date:   Mon, 15 Apr 2019 20:57:59 +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, Jim Mattson <jmattson@...gle.com>,
        Peter Shier <pshier@...gle.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 001/101] kvm: nVMX: NMI-window and interrupt-window exiting should wake L2 from HLT

[ Upstream commit 9ebdfe5230f2e50e3ba05c57723a06e90946815a ]

According to the SDM, "NMI-window exiting" VM-exits wake a logical
processor from the same inactive states as would an NMI and
"interrupt-window exiting" VM-exits wake a logical processor from the
same inactive states as would an external interrupt. Specifically, they
wake a logical processor from the shutdown state and from the states
entered using the HLT and MWAIT instructions.

Fixes: 6dfacadd5858 ("KVM: nVMX: Add support for activity state HLT")
Signed-off-by: Jim Mattson <jmattson@...gle.com>
Reviewed-by: Peter Shier <pshier@...gle.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@...el.com>
[Squashed comments of two Jim's patches and used the simplified code
 hunk provided by Sean. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/vmx.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f99f59625da5..e61ac229a6c1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -12836,11 +12836,15 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	nested_cache_shadow_vmcs12(vcpu, vmcs12);
 
 	/*
-	 * If we're entering a halted L2 vcpu and the L2 vcpu won't be woken
-	 * by event injection, halt vcpu.
+	 * If we're entering a halted L2 vcpu and the L2 vcpu won't be
+	 * awakened by event injection or by an NMI-window VM-exit or
+	 * by an interrupt-window VM-exit, halt the vcpu.
 	 */
 	if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) &&
-	    !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK)) {
+	    !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) &&
+	    !(vmcs12->cpu_based_vm_exec_control & CPU_BASED_VIRTUAL_NMI_PENDING) &&
+	    !((vmcs12->cpu_based_vm_exec_control & CPU_BASED_VIRTUAL_INTR_PENDING) &&
+	      (vmcs12->guest_rflags & X86_EFLAGS_IF))) {
 		vmx->nested.nested_run_pending = 0;
 		return kvm_vcpu_halt(vcpu);
 	}
-- 
2.19.1