linux-kernel - [PATCH 1/2] kvm: x86/mmu: Add existing trace points to TDP MMU

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Message-Id: <20201027175944.1183301-1-bgardon@google.com>
Date:   Tue, 27 Oct 2020 10:59:43 -0700
From:   Ben Gardon <bgardon@...gle.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Peter Shier <pshier@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Peter Feiner <pfeiner@...gle.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH 1/2] kvm: x86/mmu: Add existing trace points to TDP MMU

The TDP MMU was initially implemented without some of the usual
tracepoints found in mmu.c. Correct this discrepancy by adding the
missing trace points to the TDP MMU.

Tested: ran the demand paging selftest on an Intel Skylake machine with
	all the trace points used by the TDP MMU enabled and observed
	them firing with expected values.

This patch can be viewed in Gerrit at:
https://linux-review.googlesource.com/c/virt/kvm/kvm/+/3812

Signed-off-by: Ben Gardon <bgardon@...gle.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 27e381c9da6c2..047e2d966abef 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -7,6 +7,8 @@
 #include "tdp_mmu.h"
 #include "spte.h"
 
+#include <trace/events/kvm.h>
+
 #ifdef CONFIG_X86_64
 static bool __read_mostly tdp_mmu_enabled = false;
 module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644);
@@ -101,6 +103,8 @@ static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn,
 	sp->gfn = gfn;
 	sp->tdp_mmu_page = true;
 
+	trace_kvm_mmu_get_page(sp, true);
+
 	return sp;
 }
 
@@ -271,6 +275,8 @@ static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
 		pt = spte_to_child_pt(old_spte, level);
 		sp = sptep_to_sp(pt);
 
+		trace_kvm_mmu_prepare_zap_page(sp);
+
 		list_del(&sp->link);
 
 		if (sp->lpage_disallowed)
@@ -473,11 +479,13 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, int write,
 	if (unlikely(is_noslot_pfn(pfn))) {
 		new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
 		trace_mark_mmio_spte(iter->sptep, iter->gfn, new_spte);
-	} else
+	} else {
 		make_spte_ret = make_spte(vcpu, ACC_ALL, iter->level, iter->gfn,
 					 pfn, iter->old_spte, prefault, true,
 					 map_writable, !shadow_accessed_mask,
 					 &new_spte);
+		trace_kvm_mmu_set_spte(iter->level, iter->gfn, iter->sptep);
+	}
 
 	if (new_spte == iter->old_spte)
 		ret = RET_PF_SPURIOUS;
@@ -691,6 +699,8 @@ static int age_gfn_range(struct kvm *kvm, struct kvm_memory_slot *slot,
 
 		tdp_mmu_set_spte_no_acc_track(kvm, &iter, new_spte);
 		young = 1;
+
+		trace_kvm_age_page(iter.gfn, iter.level, slot, young);
 	}
 
 	return young;
-- 
2.29.0.rc2.309.g374f81d7ae-goog