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authorVipin Sharma <vipinsh@google.com>2024-11-01 13:14:37 -0700
committerSean Christopherson <seanjc@google.com>2024-11-04 19:22:53 -0800
commit4cf20d42543cff8778f70b0c29def984098641a5 (patch)
tree683109e5edef86ddc0fe1b0c0bc336e8a44d0830
parentfe140e611d3450708a962d937546c7bd164183ea (diff)
KVM: x86/mmu: Drop per-VM zapped_obsolete_pages list
Drop the per-VM zapped_obsolete_pages list now that the usage from the defunct mmu_shrinker is gone, and instead use a local list to track pages in kvm_zap_obsolete_pages(), the sole remaining user of zapped_obsolete_pages. Opportunistically add an assertion to verify and document that slots_lock must be held, i.e. that there can only be one active instance of kvm_zap_obsolete_pages() at any given time, and by doing so also prove that using a local list instead of a per-VM list doesn't change any functionality (beyond trivialities like list initialization). Signed-off-by: Vipin Sharma <vipinsh@google.com> Link: https://lore.kernel.org/r/20241101201437.1604321-2-vipinsh@google.com [sean: split to separate patch, write changelog] Signed-off-by: Sean Christopherson <seanjc@google.com>
-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--arch/x86/kvm/mmu/mmu.c8
2 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index aa8007bc520a..433e65974e2b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1306,7 +1306,6 @@ struct kvm_arch {
bool pre_fault_allowed;
struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
struct list_head active_mmu_pages;
- struct list_head zapped_obsolete_pages;
/*
* A list of kvm_mmu_page structs that, if zapped, could possibly be
* replaced by an NX huge page. A shadow page is on this list if its
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 8919ca104374..38128e7b9af1 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6367,8 +6367,11 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;
int nr_zapped, batch = 0;
+ LIST_HEAD(invalid_list);
bool unstable;
+ lockdep_assert_held(&kvm->slots_lock);
+
restart:
list_for_each_entry_safe_reverse(sp, node,
&kvm->arch.active_mmu_pages, link) {
@@ -6400,7 +6403,7 @@ restart:
}
unstable = __kvm_mmu_prepare_zap_page(kvm, sp,
- &kvm->arch.zapped_obsolete_pages, &nr_zapped);
+ &invalid_list, &nr_zapped);
batch += nr_zapped;
if (unstable)
@@ -6416,7 +6419,7 @@ restart:
* kvm_mmu_load()), and the reload in the caller ensure no vCPUs are
* running with an obsolete MMU.
*/
- kvm_mmu_commit_zap_page(kvm, &kvm->arch.zapped_obsolete_pages);
+ kvm_mmu_commit_zap_page(kvm, &invalid_list);
}
/*
@@ -6483,7 +6486,6 @@ void kvm_mmu_init_vm(struct kvm *kvm)
{
kvm->arch.shadow_mmio_value = shadow_mmio_value;
INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
- INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
INIT_LIST_HEAD(&kvm->arch.possible_nx_huge_pages);
spin_lock_init(&kvm->arch.mmu_unsync_pages_lock);