[Devel] [PATCH RHEL7 COMMIT] ms/KVM: x86: Add a return value to kvm_emulate_cpuid

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-957.10.1.vz7.85.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-957.10.1.vz7.85.7
------>
commit 9fbe4c7b58ccaf12e11068386ced1f751de849f3
Author: Kyle Huey <me at kylehuey.com>
Date:   Mon Apr 1 15:41:49 2019 +0300

    ms/KVM: x86: Add a return value to kvm_emulate_cpuid
    
    Once skipping the emulated instruction can potentially trigger an exit to
    userspace (via KVM_GUESTDBG_SINGLESTEP) kvm_emulate_cpuid will need to
    propagate a return value.
    
    Signed-off-by: Kyle Huey <khuey at kylehuey.com>
    Signed-off-by: Radim Krčmář <rkrcmar at redhat.com>
    
    https://jira.sw.ru/browse/PSBM-92865
    (cherry picked from commit 6a908b628cff81d3f1eb737327c8b726c8fdfd4e)
    Signed-off-by: Jan Dakinevich <jan.dakinevich at virtuozzo.com>
    
    =====================
    Patchset description:
    
    KVM: fix 'debug' test from 'kvm-unit-tests'
    
    Reviewed-by: Roman Kagan <rkagan at virtuozzo.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 arch/x86/kvm/cpuid.c            | 3 ++-
 arch/x86/kvm/svm.c              | 3 +--
 arch/x86/kvm/vmx.c              | 3 +--
 4 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2ca1b161e569..9f4e0005dcca 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1137,7 +1137,7 @@ int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
 struct x86_emulate_ctxt;
 
 int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port);
-void kvm_emulate_cpuid(struct kvm_vcpu *vcpu);
+int kvm_emulate_cpuid(struct kvm_vcpu *vcpu);
 int kvm_emulate_halt(struct kvm_vcpu *vcpu);
 int kvm_vcpu_halt(struct kvm_vcpu *vcpu);
 int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 4ad37e47520b..46c27a3e9b13 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -900,7 +900,7 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
 }
 EXPORT_SYMBOL_GPL(kvm_cpuid);
 
-void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
+int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 {
 	u32 function, eax, ebx, ecx, edx;
 
@@ -912,5 +912,6 @@ void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 	kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
 	kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
 	kvm_x86_ops->skip_emulated_instruction(vcpu);
+	return 1;
 }
 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 36dcd86f8728..c576ed785b10 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3498,8 +3498,7 @@ static int task_switch_interception(struct vcpu_svm *svm)
 static int cpuid_interception(struct vcpu_svm *svm)
 {
 	svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
-	kvm_emulate_cpuid(&svm->vcpu);
-	return 1;
+	return kvm_emulate_cpuid(&svm->vcpu);
 }
 
 static int iret_interception(struct vcpu_svm *svm)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4f0e649f46a8..a912ecbb5757 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6290,8 +6290,7 @@ static void vmx_set_dr7(struct kvm_vcpu *vcpu, unsigned long val)
 
 static int handle_cpuid(struct kvm_vcpu *vcpu)
 {
-	kvm_emulate_cpuid(vcpu);
-	return 1;
+	return kvm_emulate_cpuid(vcpu);
 }
 
 static int handle_rdmsr(struct kvm_vcpu *vcpu)