[PATCH v3 12/16] KVM: Move x86's perf guest info callbacks to generic KVM

Sean Christopherson
2021-09-22T00:06:58Z

Move x86's perf guest callbacks into common KVM, as they are semantically
identical to arm64's callbacks (the only other such KVM callbacks).
arm64 will convert to the common versions in a future patch.

Implement the necessary arm64 arch hooks now to avoid having to provide
stubs or a temporary #define (from x86) to avoid arm64 compilation errors
when CONFIG_GUEST_PERF_EVENTS=y.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/arm64/include/asm/kvm_host.h | 8 +++++
arch/arm64/kvm/arm.c | 5 +++
arch/x86/include/asm/kvm_host.h | 3 ++
arch/x86/kvm/x86.c | 53 +++++++------------------------
include/linux/kvm_host.h | 10 ++++++
virt/kvm/kvm_main.c | 44 +++++++++++++++++++++++++
6 files changed, 81 insertions(+), 42 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ed940aec89e0..828b6eaa2c56 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -673,6 +673,14 @@ int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa);
void kvm_perf_init(void);
void kvm_perf_teardown(void);

+#ifdef CONFIG_GUEST_PERF_EVENTS
+static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+ /* Any callback while a vCPU is loaded is considered to be in guest. */
+ return !!vcpu;
+}
+#endif
+
long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu);
gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu);
void kvm_update_stolen_time(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e9a2b8f27792..2b542fdc237e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -500,6 +500,11 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
return vcpu_mode_priv(vcpu);
}

+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+ return *vcpu_pc(vcpu);
+}
+
/* Just ensure a guest exit from a particular CPU */
static void exit_vm_noop(void *info)
{
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2d86a2dfc775..6efe4e03a6d2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1543,6 +1543,9 @@ static inline int kvm_arch_flush_remote_tlb(struct kvm *kvm)
return -ENOTSUPP;
}

+#define kvm_arch_pmi_in_guest(vcpu) \
+ ((vcpu) && (vcpu)->arch.handling_intr_from_guest)
+
int kvm_mmu_module_init(void);
void kvm_mmu_module_exit(void);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 412646b973bb..1bea616402e6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8264,43 +8264,12 @@ static void kvm_timer_init(void)
kvmclock_cpu_online, kvmclock_cpu_down_prep);
}

-static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu)
-{
- return vcpu && vcpu->arch.handling_intr_from_guest;
-}
-
-static unsigned int kvm_guest_state(void)
-{
- struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
- unsigned int state;
-
- if (!kvm_pmi_in_guest(vcpu))
- return 0;
-
- state = PERF_GUEST_ACTIVE;
- if (static_call(kvm_x86_get_cpl)(vcpu))
- state |= PERF_GUEST_USER;
-
- return state;
-}
-
-static unsigned long kvm_guest_get_ip(void)
-{
- struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
-
- /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
- if (WARN_ON_ONCE(!kvm_pmi_in_guest(vcpu)))
- return 0;
-
- return kvm_rip_read(vcpu);
-}
-
static unsigned int kvm_handle_intel_pt_intr(void)
{
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();

/* '0' on failure so that the !PT case can use a RET0 static call. */
- if (!kvm_pmi_in_guest(vcpu))
+ if (!kvm_arch_pmi_in_guest(vcpu))
return 0;

kvm_make_request(KVM_REQ_PMI, vcpu);
@@ -8309,12 +8278,6 @@ static unsigned int kvm_handle_intel_pt_intr(void)
return 1;
}

-static struct perf_guest_info_callbacks kvm_guest_cbs = {
- .state = kvm_guest_state,
- .get_ip = kvm_guest_get_ip,
- .handle_intel_pt_intr = NULL,
-};
-
#ifdef CONFIG_X86_64
static void pvclock_gtod_update_fn(struct work_struct *work)
{
@@ -11068,9 +11031,11 @@ int kvm_arch_hardware_setup(void *opaque)
memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
kvm_ops_static_call_update();

+ /* Temporary ugliness. */
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);
+ kvm_register_perf_callbacks(kvm_handle_intel_pt_intr);
+ else
+ kvm_register_perf_callbacks(NULL);

if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))
supported_xss = 0;
@@ -11099,8 +11064,7 @@ 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;
+ kvm_unregister_perf_callbacks();

static_call(kvm_x86_hardware_unsetup)();
}
@@ -11727,6 +11691,11 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
return vcpu->arch.preempted_in_kernel;
}

+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+ return kvm_rip_read(vcpu);
+}
+
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e4d712e9f760..b9255a6439f2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1163,6 +1163,16 @@ static inline bool kvm_arch_intc_initialized(struct kvm *kvm)
}
#endif

+#ifdef CONFIG_GUEST_PERF_EVENTS
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu);
+
+void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void));
+void kvm_unregister_perf_callbacks(void);
+#else
+static inline void kvm_register_perf_callbacks(void *ign) {}
+static inline void kvm_unregister_perf_callbacks(void) {}
+#endif /* CONFIG_GUEST_PERF_EVENTS */
+
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type);
void kvm_arch_destroy_vm(struct kvm *kvm);
void kvm_arch_sync_events(struct kvm *kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3e67c93ca403..179fb110a00f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5460,6 +5460,50 @@ struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
return &kvm_running_vcpu;
}

+#ifdef CONFIG_GUEST_PERF_EVENTS
+static unsigned int kvm_guest_state(void)
+{
+ struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
+ unsigned int state;
+
+ if (!kvm_arch_pmi_in_guest(vcpu))
+ return 0;
+
+ state = PERF_GUEST_ACTIVE;
+ if (!kvm_arch_vcpu_in_kernel(vcpu))
+ state |= PERF_GUEST_USER;
+
+ return state;
+}
+
+static unsigned long kvm_guest_get_ip(void)
+{
+ struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
+
+ /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
+ if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu)))
+ return 0;
+
+ return kvm_arch_vcpu_get_ip(vcpu);
+}
+
+static struct perf_guest_info_callbacks kvm_guest_cbs = {
+ .state = kvm_guest_state,
+ .get_ip = kvm_guest_get_ip,
+ .handle_intel_pt_intr = NULL,
+};
+
+void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void))
+{
+ kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler;
+ perf_register_guest_info_callbacks(&kvm_guest_cbs);
+}
+void kvm_unregister_perf_callbacks(void)
+{
+ perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
+}
+#endif
+
struct kvm_cpu_compat_check {
void *opaque;
int *ret;
--
2.33.0.464.g1972c5931b-goog