Replace MMU_DEBUG, which requires manually modifying KVM to enable the
macro, with a proper Kconfig, KVM_PROVE_MMU. Now that pgprintk() and
rmap_printk() are gone, i.e. the macro guards only KVM_MMU_WARN_ON() and
won't flood the kernel logs, enabling the option for debug kernels is both
desirable and feasible.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/Kconfig | 13 +++++++++++++
arch/x86/kvm/mmu/mmu.c | 4 ++--
arch/x86/kvm/mmu/mmu_internal.h | 4 +---
3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 8e578311ca9d..cccedb424324 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -139,6 +139,19 @@ config KVM_XEN
If in doubt, say "N".
+config KVM_PROVE_MMU
+ bool "Prove KVM MMU correctness"
+ depends on DEBUG_KERNEL
+ depends on KVM
+ depends on EXPERT
+ help
+ Enables runtime assertions in KVM's MMU that are too costly to enable
+ in anything remotely resembling a production environment, e.g. this
+ gates code that verifies a to-be-freed page table doesn't have any
+ present SPTEs.
+
+ If in doubt, say "N".
+
config KVM_EXTERNAL_WRITE_TRACKING
bool
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4731d2bf5af6..d209d466d58f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1686,7 +1686,7 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
return young;
}
-#ifdef MMU_DEBUG
+#ifdef CONFIG_KVM_PROVE_MMU
static int is_empty_shadow_page(u64 *spt)
{
u64 *pos;
@@ -1700,7 +1700,7 @@ static int is_empty_shadow_page(u64 *spt)
}
return 1;
}
-#endif
+#endif /* CONFIG_KVM_PROVE_MMU */
/*
* This value is the sum of all of the kvm instances's
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index cfe925fefa68..40e74db6a7d5 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -6,9 +6,7 @@
#include <linux/kvm_host.h>
#include <asm/kvm_host.h>
-#undef MMU_DEBUG
-
-#ifdef MMU_DEBUG
+#ifdef CONFIG_KVM_PROVE_MMU
#define KVM_MMU_WARN_ON(x) WARN_ON_ONCE(x)
#else
#define KVM_MMU_WARN_ON(x) do { } while (0)
--
2.40.1.606.ga4b1b128d6-goog
