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

On Mon, 11 Oct 2021 15:46:25 +0100,
Sean Christopherson [off-list ref] wrote:

On Mon, Oct 11, 2021, Marc Zyngier wrote:

quoted

On Wed, 22 Sep 2021 01:05:29 +0100, Sean Christopherson [off-list ref] wrote:

quoted

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)

Pardon my x86 ignorance, what is PMI? PMU Interrupt?

Ya, Performance Monitoring Interrupt.  I didn't realize the term wasn't
common perf terminology.  Maybe kvm_arch_perf_events_in_guest() to be
less x86-centric?

Up to you. I would be happy with just a comment.

quoted

quoted

+{
+	/* Any callback while a vCPU is loaded is considered to be in guest. */
+	return !!vcpu;
+}
+#endif

Do you really need this #ifdef?

Nope, should compile fine without it, though simply dropping the #ifdef
would make make the semantics of the function wrong, even if nothing
consumes it.  Tweak it to use IS_ENABLED()?

	return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;

LGTM.

	M.

-- 
Without deviation from the norm, progress is not possible.