[PATCH v4 4/4] KVM: arm64/mmu: count KVM s2 mmu usage in secondary pagetable stats

Yosry Ahmed
2022-04-29T20:12:12Z

Count the pages used by KVM in arm64 for stage2 mmu in secondary pagetable
stats.

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
---
arch/arm64/kvm/mmu.c | 35 +++++++++++++++++++++++++++++++----
1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 53ae2c0640bc..fc5030307cce 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -92,9 +92,13 @@ static bool kvm_is_device_pfn(unsigned long pfn)
static void *stage2_memcache_zalloc_page(void *arg)
{
struct kvm_mmu_memory_cache *mc = arg;
+ void *virt;

/* Allocated with __GFP_ZERO, so no need to zero */
- return kvm_mmu_memory_cache_alloc(mc);
+ virt = kvm_mmu_memory_cache_alloc(mc);
+ if (virt)
+ kvm_account_pgtable_pages(virt, +1);
+ return virt;
}

static void *kvm_host_zalloc_pages_exact(size_t size)
@@ -102,6 +106,20 @@ static void *kvm_host_zalloc_pages_exact(size_t size)
return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
}

+static void *kvm_s2_zalloc_pages_exact(size_t size)
+{
+ void *virt = kvm_host_zalloc_pages_exact(size);
+ if (virt)
+ kvm_account_pgtable_pages(virt, +(size >> PAGE_SHIFT));
+ return virt;
+}
+
+static void kvm_s2_free_pages_exact(void *virt, size_t size)
+{
+ kvm_account_pgtable_pages(virt, -(size >> PAGE_SHIFT));
+ free_pages_exact(virt, size);
+}
+
static void kvm_host_get_page(void *addr)
{
get_page(virt_to_page(addr));
@@ -112,6 +130,15 @@ static void kvm_host_put_page(void *addr)
put_page(virt_to_page(addr));
}

+static void kvm_s2_put_page(void *addr)
+{
+ struct page *p = virt_to_page(addr);
+ /* Dropping last refcount, the page will be freed */
+ if (page_count(p) == 1)
+ kvm_account_pgtable_pages(addr, -1);
+ put_page(p);
+}
+
static int kvm_host_page_count(void *addr)
{
return page_count(virt_to_page(addr));
@@ -603,10 +630,10 @@ static int get_user_mapping_size(struct kvm *kvm, u64 addr)

static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
.zalloc_page = stage2_memcache_zalloc_page,
- .zalloc_pages_exact = kvm_host_zalloc_pages_exact,
- .free_pages_exact = free_pages_exact,
+ .zalloc_pages_exact = kvm_s2_zalloc_pages_exact,
+ .free_pages_exact = kvm_s2_free_pages_exact,
.get_page = kvm_host_get_page,
- .put_page = kvm_host_put_page,
+ .put_page = kvm_s2_put_page,
.page_count = kvm_host_page_count,
.phys_to_virt = kvm_host_va,
.virt_to_phys = kvm_host_pa,
--
2.36.0.464.gb9c8b46e94-goog