[PATCH v4 03/17] KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest

[Sean Christopherson <seanjc@xxxxxxxxxx>]

Override the Processor Trace (PT) interrupt handler for guest mode if and
only if PT is configured for host+guest mode, i.e. is being used
independently by both host and guest.  If PT is configured for system
mode, the host fully controls PT and must handle all events.

Fixes: 8479e04e7d6b ("KVM: x86: Inject PMI for KVM guest")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Like Xu <like.xu.linux@xxxxxxxxx>
Reported-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Reported-by: Artem Kashkanov <artem.kashkanov@xxxxxxxxx>
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/vmx/vmx.c          | 1 +
 arch/x86/kvm/x86.c              | 5 ++++-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2acf37cc1991..bf0a9ce53750 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1514,6 +1514,7 @@ struct kvm_x86_init_ops {
        int (*disabled_by_bios)(void);
        int (*check_processor_compatibility)(void);
        int (*hardware_setup)(void);
+       bool (*intel_pt_intr_in_guest)(void);
 
        struct kvm_x86_ops *runtime_ops;
 };
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 76861b66bbcf..0927d07b2efb 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7918,6 +7918,7 @@ static struct kvm_x86_init_ops vmx_init_ops __initdata = {
        .disabled_by_bios = vmx_disabled_by_bios,
        .check_processor_compatibility = vmx_check_processor_compat,
        .hardware_setup = hardware_setup,
+       .intel_pt_intr_in_guest = vmx_pt_mode_is_host_guest,
 
        .runtime_ops = &vmx_x86_ops,
 };
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 021b2c1ac9f0..021d3f5364b2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8451,7 +8451,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
        .is_in_guest            = kvm_is_in_guest,
        .is_user_mode           = kvm_is_user_mode,
        .get_guest_ip           = kvm_get_guest_ip,
-       .handle_intel_pt_intr   = kvm_handle_intel_pt_intr,
+       .handle_intel_pt_intr   = NULL,
 };
 
 #ifdef CONFIG_X86_64
@@ -11146,6 +11146,8 @@ int kvm_arch_hardware_setup(void *opaque)
        memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
        kvm_ops_static_call_update();
 
+       if (ops->intel_pt_intr_in_guest && ops->intel_pt_intr_in_guest())
+               kvm_guest_cbs.handle_intel_pt_intr = kvm_handle_intel_pt_intr;
        perf_register_guest_info_callbacks(&kvm_guest_cbs);
 
        if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))
@@ -11176,6 +11178,7 @@ int kvm_arch_hardware_setup(void *opaque)
 void kvm_arch_hardware_unsetup(void)
 {
        perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
+       kvm_guest_cbs.handle_intel_pt_intr = NULL;
 
        static_call(kvm_x86_hardware_unsetup)();
 }
-- 
2.34.0.rc0.344.g81b53c2807-goog