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Subject[PATCH 5.16 08/28] KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest
Date
From: Sean Christopherson <seanjc@google.com>

commit f4b027c5c8199abd4fb6f00d67d380548dbfdfa8 upstream.

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")
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reported-by: Artem Kashkanov <artem.kashkanov@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211111020738.2512932-4-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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(-)

--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1519,6 +1519,7 @@ 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;
};
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7905,6 +7905,7 @@ static struct kvm_x86_init_ops vmx_init_
.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,
};
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8560,7 +8560,7 @@ static struct perf_guest_info_callbacks
.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
@@ -11266,6 +11266,8 @@ 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))
@@ -11296,6 +11298,7 @@ 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)();
}

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