[PATCH 01/15] KVM: x86: Register perf callbacks after calling vendor's hardware_setup()
From: Sean Christopherson <seanjc@google.com>
Date: 2021-08-27 00:57:38
Also in:
kvm, kvmarm, linux-arm-kernel, linux-riscv, lkml, xen-devel
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Wait to register perf callbacks until after doing vendor hardaware setup. VMX's hardware_setup() configures Intel Processor Trace (PT) mode, and a future fix to register the Intel PT guest interrupt hook if and only if Intel PT is exposed to the guest will consume the configured PT mode. Delaying registration to hardware setup is effectively a nop as KVM's perf hooks all pivot on the per-CPU current_vcpu, which is non-NULL only when KVM is handling an IRQ/NMI in a VM-Exit path. I.e. current_vcpu will be NULL throughout both kvm_arch_init() and kvm_arch_hardware_setup(). Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Artem Kashkanov <redacted> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/x86.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 86539c1686fa..fb6015f97f9e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c@@ -8426,8 +8426,6 @@ int kvm_arch_init(void *opaque) kvm_timer_init(); - perf_register_guest_info_callbacks(&kvm_guest_cbs); - if (boot_cpu_has(X86_FEATURE_XSAVE)) { host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK); supported_xcr0 = host_xcr0 & KVM_SUPPORTED_XCR0;
@@ -8461,7 +8459,6 @@ void kvm_arch_exit(void) clear_hv_tscchange_cb(); #endif kvm_lapic_exit(); - perf_unregister_guest_info_callbacks(&kvm_guest_cbs); if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) cpufreq_unregister_notifier(&kvmclock_cpufreq_notifier_block,
@@ -11064,6 +11061,8 @@ int kvm_arch_hardware_setup(void *opaque) memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops)); kvm_ops_static_call_update(); + perf_register_guest_info_callbacks(&kvm_guest_cbs); + if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES)) supported_xss = 0;
@@ -11091,6 +11090,8 @@ int kvm_arch_hardware_setup(void *opaque) void kvm_arch_hardware_unsetup(void) { + perf_unregister_guest_info_callbacks(&kvm_guest_cbs); + static_call(kvm_x86_hardware_unsetup)(); }
--
2.33.0.259.gc128427fd7-goog