[v2,6/9] KVM: x86/mmu: Replace MMU_DEBUG with proper KVM_PROVE_MMU Kconfig
Commit Message
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@google.com>
---
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(-)
@@ -138,6 +138,19 @@ 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
@@ -1693,7 +1693,7 @@ 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;
@@ -1707,7 +1707,7 @@ 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
@@ -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)