fix: KVM: x86/mmu: Return unique RET_PF_* values if the fault was fixed (v5.10)
authorMichael Jeanson <mjeanson@efficios.com>
Mon, 26 Oct 2020 21:07:13 +0000 (17:07 -0400)
committerMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fri, 20 Nov 2020 20:39:11 +0000 (15:39 -0500)
See upstream commit :

  commit c4371c2a682e0da1ed2cd7e3c5496f055d873554
  Author: Sean Christopherson <sean.j.christopherson@intel.com>
  Date:   Wed Sep 23 15:04:24 2020 -0700

    KVM: x86/mmu: Return unique RET_PF_* values if the fault was fixed

    Introduce RET_PF_FIXED and RET_PF_SPURIOUS to provide unique return
    values instead of overloading RET_PF_RETRY.  In the short term, the
    unique values add clarity to the code and RET_PF_SPURIOUS will be used
    by set_spte() to avoid unnecessary work for spurious faults.

    In the long term, TDX will use RET_PF_FIXED to deterministically map
    memory during pre-boot.  The page fault flow may bail early for benign
    reasons, e.g. if the mmu_notifier fires for an unrelated address.  With
    only RET_PF_RETRY, it's impossible for the caller to distinguish between
    "cool, page is mapped" and "darn, need to try again", and thus cannot
    handle benign cases like the mmu_notifier retry.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ie0855c78852b45f588e131fe2463e15aae1bc023

include/instrumentation/events/arch/x86/kvm/mmutrace.h

index 8e5bf1c1e44c002665d2555d8c06ab61bf0e5b49..f585d027972c241f3a0921bdffc437a17e5ce6e0 100644 (file)
@@ -233,7 +233,27 @@ LTTNG_TRACEPOINT_EVENT_MAP(
        )
 )
 
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0) || \
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,10,0))
+LTTNG_TRACEPOINT_EVENT_MAP(
+       fast_page_fault,
+
+       kvm_mmu_fast_page_fault,
+
+       TP_PROTO(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u32 error_code,
+                u64 *sptep, u64 old_spte, int ret),
+       TP_ARGS(vcpu, cr2_or_gpa, error_code, sptep, old_spte, ret),
+
+       TP_FIELDS(
+               ctf_integer(int, vcpu_id, vcpu->vcpu_id)
+               ctf_integer(gpa_t, cr2_or_gpa, cr2_or_gpa)
+               ctf_integer(u32, error_code, error_code)
+               ctf_integer_hex(u64 *, sptep, sptep)
+               ctf_integer(u64, old_spte, old_spte)
+               ctf_integer(u64, new_spte, *sptep)
+               ctf_integer(int, ret, ret)
+       )
+)
+#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0) || \
        LTTNG_KERNEL_RANGE(4,19,103, 4,20,0) || \
        LTTNG_KERNEL_RANGE(5,4,19, 5,5,0) || \
        LTTNG_KERNEL_RANGE(5,5,3, 5,6,0) || \
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