2021-04-19 22:16:00

by Ben Gardon

Subject: [PATCH 1/2] KVM: x86/mmu: Wrap kvm_mmu_zap_all_fast TDP MMU code in ifdefs

The TDP MMU code in kvm_mmu_zap_all_fast is only needed with
CONFIG_X86_64 and creates a build error without that setting. Since the
TDP MMU can only be enabled with CONFIG_X86_64, wrap those code blocks
in ifdefs.

Fixes: 1336c692abad ("KVM: x86/mmu: Fast invalidation for TDP MMU")

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Ben Gardon <[email protected]>
---
arch/x86/kvm/mmu/mmu.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0f311c9bf9c6..3ae59c8e129b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5407,7 +5407,9 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm)
*/
static void kvm_mmu_zap_all_fast(struct kvm *kvm)
{
+#ifdef CONFIG_X86_64
struct kvm_mmu_page *root;
+#endif /* CONFIG_X86_64 */

lockdep_assert_held(&kvm->slots_lock);

@@ -5424,6 +5426,7 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
kvm->arch.mmu_valid_gen = kvm->arch.mmu_valid_gen ? 0 : 1;


+#ifdef CONFIG_X86_64
if (is_tdp_mmu_enabled(kvm)) {
/*
* Mark each TDP MMU root as invalid so that other threads
@@ -5456,6 +5459,7 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
if (refcount_inc_not_zero(&root->tdp_mmu_root_count))
root->role.invalid = true;
}
+#endif /* CONFIG_X86_64 */

/*
* Notify all vcpus to reload its shadow page table and flush TLB.
@@ -5471,11 +5475,13 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)

write_unlock(&kvm->mmu_lock);

+#ifdef CONFIG_X86_64
if (is_tdp_mmu_enabled(kvm)) {
read_lock(&kvm->mmu_lock);
kvm_tdp_mmu_zap_invalidated_roots(kvm);
read_unlock(&kvm->mmu_lock);
}
+#endif /* CONFIG_X86_64 */
}

static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
--
2.31.1.368.gbe11c130af-goog

2021-04-19 22:41:25

by Ben Gardon

Subject: [PATCH 2/2] KVM: x86/mmu: Fix typo in for_each_tdp_mmu_root

There's a typo in for_each_tdp_mmu_root which breaks compilation with
certain configurations. Fix it.

Fixes: 078d47ee71d6 ("KVM: x86/mmu: Protect the tdp_mmu_roots list with RCU")

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Ben Gardon <[email protected]>
---
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 8ce8d0916042..f0aef4969754 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -152,7 +152,7 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
#define for_each_tdp_mmu_root(_kvm, _root, _as_id) \
list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link, \
lockdep_is_held_type(&kvm->mmu_lock, 0) || \
- lockdep_is_help(&kvm->arch.tdp_mmu_pages_lock)) \
+ lockdep_is_held(&kvm->arch.tdp_mmu_pages_lock)) \
if (kvm_mmu_page_as_id(_root) != _as_id) { \
} else

--
2.31.1.368.gbe11c130af-goog